The patient: A 6-year-old boy in the Netherlands

The symptoms: The child was receiving a blood transfusion as a treatment for lymphoblastic leukemia, a type of blood cancer that originates in bone marrow, when he experienced a severe allergic reaction. His blood pressure dropped, and he developed a rash. Swelling appeared around his lips, tongue and eyelids, and he had difficulty breathing. This type of allergic response, known as anaphylaxis, can be life-threatening.

What happened next: Doctors treated the patient with the hormone epinephrine (also called adrenaline), which quickly reduces tissue swelling caused by anaphylaxis while also raising blood pressure and easing restricted breathing. The child recovered after about 30 minutes.

His doctors collected blood samples immediately after the reaction, and these contained unusually high levels of a type of protein called mast-cell tryptase, which is released by certain immune cells during anaphylaxis. However, the physicians were puzzled as to what had caused the extreme reaction, they wrote in a report of the case.

The diagnosis: The patient's mother told the doctors that her child had a similar allergic response to peanuts when he was about 1 year old, and since then, they'd omitted peanuts from his diet. The doctors then contacted the five blood donors who had provided the boy's most recent transfusion, and they learned that three of the five donors had eaten handfuls of peanuts the evening before they donated blood.

A protein in peanuts called Ara h2 is one of the main allergens that set off allergic reactions in people's immune systems. One of the building blocks of the allergen, called DRP-Ara h2, takes more than 24 hours to digest and remains capable of binding to receptors and triggering an allergic response throughout that time.

To see if this allergen could have played a role in the patient's reaction, the doctors performed another blood test that detects antibodies and is used for identifying allergic sensitivities. The test confirmed that the patient was allergic to peanuts and that antibodies against Ara h2 and DRP-Ara h2m were present in his blood post-infusion. These antibodies would have been produced in response to Ara h2 entering the bloodstream.

"These data are consistent with the hypothesis that the consumption of peanuts by the donors before blood donation provided the trigger for this patient's transfusion reaction," the doctors reported.

The treatment: The patient didn't require any further treatment after the epinephrine that was administered immediately to reverse anaphylaxis.

What makes the case unique: Allergic reactions during blood transfusions are rare, although estimates of their exact frequency vary. Some estimates suggest that they occur in about 0.001% to 0.006% of transfusions, while others find they occur in 0.1% of transfusions.

The triggers that set off these allergic responses are seldom identified. Prior to this case, other researchers suggested that blood transfusions could passively transfer food allergens from the donor to the recipient. Indeed, a growing body of evidence suggests that this may be more common than expected.

The child's response highlights the importance of identifying food allergies in people receiving blood transfusions, the child's doctors concluded, as well as the necessity of reviewing blood donors' recent diet histories to screen for potential allergens that could affect sensitive recipients.

"It is possible that allergens transferred in blood products to other patients have led to reactions that have gone unexplained and unreported," the doctors wrote in the case report.

This article is for informational purposes only and is not meant to offer medical advice.

Can you guess the diagnosis in these strange medical cases? Find out with our diagnostic dilemma quiz!

The patient: A 14-year-old boy in the United Kingdom

The symptoms: The teen was brought to his family's general practitioner because he felt unusually tired. His doctor asked about the boy's eating habits and described him as a "fussy eater" in notes from the appointment. The doctor also indicated that the teen had no symptoms other than tiredness, according to a report of the case.

Tests revealed that the teen had mild anemia and low levels of vitamin B12, which comes from a person's diet because the body does not produce it. The body needs vitamin B12 for maintaining the health of red blood cells and the nervous system. The teen's doctor provided dietary advice and prescribed supplementary B12 injections.

What happened next: Later, at age 15, the teen began developing problems with his sight. An eye exam detected no abnormalities, and the ophthalmologist was unable to determine the cause of the vision loss, which worsened over time. When the patient was 17 years old, his general practitioner referred him to a neuro-ophthalmologist for further testing. (Neuro-ophthalmologists can assess vision problems related to the nervous system.)

Additional vision tests showed that the patient's visual acuity — a measurement of a person's ability to accurately see details from certain distances — was 20/200 in both eyes. In other words, objects that would be visible to a person with normal (20/20) vision at a distance of 200 feet were not clearly visible to him beyond a distance of 20 feet. Vision of 20/200 or lower falls within the parameters of legal blindness, according to the American Foundation for the Blind.

When asked, the patient denied using drugs, alcohol or tobacco, and his eyes showed no signs of disease, nor were they scarred or injured. The results of a neurological exam were normal.

However, blood tests showed that his red blood cells were enlarged, which can suggest vitamin deficiencies. His blood levels of copper and vitamin D were lower than normal. Furthermore, elevated concentrations of the amino acid homocysteine and methylmalonic acid — compounds that B12 helps to break down — further hinted that he was deficient in the vitamin, as at earlier examinations.

The diagnosis: The patient admitted that he was no longer taking the recommended B12 injections. (The case report did not indicate exactly when he had stopped.) His body mass index (BMI) was normal, and he was of average weight for his height. But because his B12 levels were low, the doctors questioned him about his diet.

He replied that he could not tolerate certain food textures; as a result, since elementary school, he had avoided most foods. For years, his daily diet consisted of fast-food french fries, white bread, potato chips, sausages and processed ham.

This diet lacked vital nutrients, leading to a condition called nutritional optic neuropathy, a rare type of vision loss that is often caused by severe deficits in B12 and other B vitamins. It causes atrophy of the optic nerve, which relays information from the eye to the parts of the brain that process vision. Copper deficiencies have also been linked to this type of optic neuropathy and to enlarged red blood cells, according to the report's authors.

The treatment: The doctors prescribed the teen supplements to correct his nutritional deficiencies and referred him to mental health services to treat his food aversions, which the doctors identified as a type of eating disorder.

Following treatment, the patient's vision did not deteriorate further. However, there was no improvement in his sight. Nutritional optic neuropathy may be reversed when caught early, but if the optic nerve becomes atrophied, the vision loss is permanent, the physicians explained in the report.

What makes the case unique: Nutritional optic neuropathy is rarely caused by dietary deficiencies alone. Historically, cases in the medical literature have generally been associated with malnutrition caused by war and famine. More recent cases have usually involved both nutritional deficits and smoking or abuse of alcohol or drugs.

In some instances, this type of neuropathy results from inflammatory bowel disease or bariatric surgery, which limit the body's absorption of certain nutrients. It can also stem from restrictive diets that are not adequately supplemented with missing vitamins and minerals.

The teen's case is also unusual because his normal BMI masked the vitamin deficiencies that caused his blindness. In other words, doctors may have overlooked his dietary deficits because his weight was within a normal range.

Moving forward, "nutritional optic neuropathy should be considered in any patient with unexplained vision symptoms and poor diet, regardless of BMI," the authors wrote in the report.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

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The patient: An 83-year-old man in Belgium

The symptoms: The man sought medical attention at a hospital because the muscles on one side of his face had weakened suddenly, causing it to droop — a condition called unilateral peripheral facial-nerve palsy. He had also recently had a fever, which had since resolved.

Tests run by the neurology department found the man had anemia, fatty liver disease and an enlarged spleen. Combined with his recent fever, these findings led the team to assume he had a viral infection. However, he tested negative for a variety of germs, including Epstein-Barr virus, which causes mono; cytomegalovirus; human immunodeficiency virus (HIV); and hepatitis A, B, C, and E.

The man's liver abnormalities hadn't resolved by one week later, but his facial-nerve palsy cleared following a 10-day course of a strong corticosteroid. But then, over the next month, the man's knees and ankles became stiff and painful, and his legs and feet — and occasionally his face, arms and hands — began to swell. He reported feeling generally unwell, he had gained 11 pounds (5 kilograms), and his urine had darkened even though he had been drinking more water than usual. All of these signs pointed to problems with his kidney function.

Besides the conditions uncovered on his recent medical examinations, the patient had long-standing high blood pressure, high cholesterol, an enlarged prostate and chronic obstructive pulmonary disease (COPD), for which he was taking medications. He had also been diagnosed with rectal cancer 20 years beforehand and received various treatments over the years. He and his wife of 50 years had been sexually inactive since that cancer treatment, he told his doctors.

What happened next: After weeks spent in and out of the hospital, the man went to an emergency room after his skin suddenly became intensely itchy. He had a red, scaly rash on his calves. A neurological exam revealed "normal motor strength, sensation, reflexes, coordination, and gait," the doctors wrote in a report of the case.

At the ER, the patient was questioned further about his medical history, at which point he told doctors that, during his military service as a young man, he'd had unprotected sex with multiple casual partners. He reported being treated for various sexually transmitted infections (STIs) during that time but had forgotten the specific diagnoses.

Tests revealed that the patient was anemic and that his urine contained blood and an abnormal amount of protein. Additionally, a test for autoimmune diseases found abnormally high levels of antinuclear antibodies, which target the control centers of cells that house DNA. Because the patient had recently had facial-nerve palsy, the doctors analyzed his cerebral spinal fluid — the clear fluid that surrounds the brain and spinal cord. This revealed elevated levels of white blood cells, which hinted at an active infection.

The diagnosis: While tests for HIV and tuberculosis came back negative, an assay for Treponema pallidum, the bacterium that causes syphilis, was positive, confirming that the patient had an active syphilis infection.

Syphilis infections can progress through four stages, each with different symptoms. If an infected person doesn't get effective treatment during the primary and secondary stages, the bacteria can go latent, sometimes for decades. And in a minority of cases, latent syphilis can awaken and cause a late, or tertiary, infection.

Based on his positive T. pallidum test, rash, general unwell feeling, abnormal liver results, high urinary protein count, leg swelling, facial drooping and swollen lymph nodes, the man's doctors diagnosed him with secondary syphilis with early neurosyphilis, in which the bacteria attack the nervous system.

The treatment: The patient had been given a single injection of penicillin before the test results confirmed that his infection had neurological involvement. He was subsequently given a 14-day course of intravenous penicillin, which is the recommended treatment for neurosyphilis, according to the case report.

The severe itching was treated with antihistamines, and he was prescribed diuretics to reduce the swelling in his legs. The rash, itching and swelling had improved by his one-month follow-up appointment, and his liver tests and urinary output had normalized.

Public health authorities were informed of the patient's diagnosis, and his wife was referred for testing. The case report does not note whether his wife tested positive for syphilis.

What makes the case unique: Secondary syphilis normally occurs within the first year of an untreated infection and only rarely develops after four years have passed. Normally, smooth, hard sores appear on the mouth or genitals during primary syphilis, and once those sores disappear, secondary syphilis sets in within months, if left untreated.

"Although the patient's history of multiple sexually transmitted infections as a young man prompted testing for syphilis, an exposure from that period would not be expected to explain his current presentation," his doctors wrote.

There's a possibility that the man had a latent infection that recently reactivated, perhaps due to the immune-suppressing effect of his recent steroid treatment. But you'd expect the reactivation to cause only symptoms of tertiary syphilis — like nervous system problems — not symptoms associated with secondary syphilis, like fever, rash and weight loss.

Therefore, exactly when the man contracted the infection is uncertain. "A more recent, unreported exposure must be considered," the doctors wrote.

It is also rare for syphilis to affect the liver and kidneys, occurring in less than 10% of cases, according to the case report.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

This article was first published Feb. 18, 2026.

The patient: A woman in her early 50s in Canada

The symptoms: The woman started occasionally hearing her name being called when she was alone, usually in quiet surroundings. Later, the sounds evolved into indistinct murmurs. These voices seemed to come from outside her head rather than from her own thoughts. They never spoke directly to her, commented on her actions or gave commands.

What happened next: In the next two years after she began hearing voices, the woman made several trips to emergency departments and had brief psychiatric admissions. Because hearing voices is commonly associated with psychosis — symptoms that occur when people experience a disconnect from reality — doctors diagnosed her with "unspecified psychosis" and attempted various treatments.

They first tried the antipsychotic risperidone, gradually increasing the dose, but the voices did not go away. Doctors then switched the patient to aripiprazole, but the hallucinations remained unchanged. Next, they tried haloperidol, and although the woman said the medication made her feel calmer and less distressed, the voices persisted.

As they conducted further psychiatric evaluations, the doctors noticed that the woman frequently leaned forward during conversations, cupped an ear and asked people to repeat themselves. About four to six months after her first contact with a psychiatric team, she was referred for hearing tests. These tests revealed hearing loss in both ears, ranging from moderate to severe in one ear and mild to profound in the other.

About two months later, the woman was fitted with hearing aids in both ears, which improved her hearing. The voices did not go away, however.

Brain scans showed no abnormalities, and blood tests came back normal. Neurological evaluations turned up no evidence of other explanations. Meanwhile, the woman continued working full time, managing her household and maintaining an active social life. She showed no signs of paranoia, delusions, disorganized thinking or the decline in daily functioning that doctors would typically expect to be associated with a psychotic disorder.

The diagnosis: Based on the woman's stable functioning, hearing impairment and lack of other clinical abnormalities, the doctors concluded that her auditory hallucinations stemmed from sensory deprivation caused by hearing loss.

Reduced sound input from the ears can make auditory regions of the brain unusually active, causing them to "fill in" missing sounds, the doctors explained in a report of the case. A related phenomenon is known as musical hallucinosis, in which people with hearing impairments hear songs, melodies or other forms of music that are not actually playing.

The treatment: Because neither antipsychotic medications nor hearing aids eliminated the patient's hallucinations, doctors shifted their focus toward helping the woman cope with them.

They taught her about the connection between hearing loss and hallucinations and advised her to pursue psychotherapy aimed at reducing the distress associated with the voices and improving her coping strategies for dealing with their persistence. At the time the report was published, in May 2026, she was waiting to begin this therapy.

What makes the case unique: In their report, the doctors noted that most published accounts of this phenomenon have described patients' hallucinations improving or resolving after their hearing impairment was treated. Persistent hallucinations after treatment are rare. In the woman's case, however, the voices persisted despite the use of hearing aids.

The doctors suggest that prolonged hearing loss may cause lasting changes in the brain that do not immediately reverse once hearing improves. (The case report does not note how long the woman's hearing had likely been impaired.)

The case also serves as a reminder that hearing voices does not always indicate psychosis, the doctors concluded. Because the woman's hearing loss was recognized only after years of symptoms and several unsuccessful medication trials, the report authors argued that doctors should consider running hearing assessments early in patients with isolated auditory hallucinations, especially when their insight and daily functioning remain intact.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

Can you guess the diagnosis in these strange medical cases? Find out with our diagnostic dilemma quiz!

The patient: A 63-year-old woman in Massachusetts

The symptoms: The patient went to the emergency department after experiencing nausea and vomiting for about a month, along with decreased appetite. She told doctors that she'd also experienced a burning pain in her upper abdomen and right side of her torso, which wrapped around to her back. She'd tried treating these symptoms with two common over-the-counter medications for acid reflux, but the treatments didn't help.

In the year prior, the patient had started taking semaglutide, a type of drug known as a GLP-1 receptor agonist — the same class of drug as Ozempic. These injected drugs are used to treat type 2 diabetes and assist in chronic weight management; in this case, the woman had a history of type 2 diabetes and obesity. Since starting the medication, she'd lost about 40 pounds (18 kilograms), but notably, that weight loss had accelerated over the previous month, she noted.

What happened next: Doctors took a CT scan of the patient's abdomen and pelvis. This revealed that the bile ducts, which move bile from the liver to the gallbladder and small intestine, were slightly dilated. The woman also had "heavy stool burden" but no signs of obstructions in her bowels, and her stomach was slightly stretched out due to carrying "semisolid material."

To take a closer look, the medical team then used magnetic resonance cholangiopancreatography, a noninvasive scan that examines the bile ducts, gallbladder, pancreas and pancreatic ducts. The scan confirmed that the bile ducts were dilated and revealed a mass in the stomach that appeared to be trapped air. The doctors then examined the upper digestive tract, from the esophagus to the top of the small intestine, with an endoscope.

The diagnosis: The endoscopy revealed a large mass in the woman's stomach, known as a gastric bezoar. These masses are tightly packed blobs of partially digested or undigested materials.

The treatment: Semaglutide and other GLP-1 agonists typically cause delayed gastric emptying, which means they slow the rate at which the stomach empties its contents into the intestines. The woman was taken off that medication upon hospital admission.

The next step with a bezoar is to try and dissolve the mass while it's still in the stomach — and evidence suggests a good way to do this is to give the patient soda.

"Existing evidence, largely from case series and anecdotal experiences, supports the administration of 3 liters [0.8 gallons] of cola, either orally or through a nasogastric tube, within a 12-hour window," doctors noted in a report of the case. "It is not well understood whether acidity, carbonation, or another mechanism accounts for dissolution of the bezoar."

Due to the patient's history of diabetes, she was given diet cola. She also didn't enjoy carbonated beverages, so the typical prescription of 3 liters of soda was cut down to 1.5 liters (0.4 gallons). On the second day after starting this treatment, the patient noted a "tugging" sensation in her abdomen followed by relief of her nausea and abdominal discomfort. An endoscopic exam revealed that the bezoar was no longer stuck in her stomach.

The woman then transitioned to a typical diet in the hospital, and by the time she was discharged, she had no nausea, vomiting or abdominal pain. She did not restart semaglutide but was prescribed acid reflux medication to take daily. She reported that her appetite increased after hospital discharge and her weight rebounded a bit over the following months. Her abdominal symptoms had not returned within a few months of discharge.

What makes the case unique: Gastric bezoars are fairly rare, the report noted. They are found in less than 0.5% of endoscopies of the upper digestive tract. Common symptoms of the condition, such as pain, nausea, vomiting and abdominal discomfort, also appear in many more-common disorders, so they don't necessarily point to the presence of a bezoar in all cases.

The most common type of gastric bezoar is formed of plant fibers and called a "phytobezoar." Eating lots of certain foods, such as persimmons, pineapples, raisins or celery, can raise the risk of phytobezoars because the plants contain a high concentration of indigestible components, such as cellulose, lignins and certain tannins.

However, various medical conditions, procedures and drugs can also raise the risk of bezoars. These include anatomical changes related to bariatric or other gastric surgeries, autonomic nerve damage, and medications that cause delayed gastric emptying, such as GLP-1s. In the woman's case, semaglutide was likely to blame for her bezoar, and discontinuing the treatment helped resolve the problem.

The cola she consumed also helped. Although that course of treatment sounds strange on paper, it is the preferred first-line treatment over using a scope to physically break up the bezoar in the patient's stomach.

"Bezoars formed from food material may be initially managed with oral administration of cola in patients in a clinically stable condition," the report said. "This intervention is generally cost-effective and is associated with a lower risk of complications than invasive procedures."

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

This article was first published Oct. 15, 2025.

The patient: A man in his 20s in Edinburgh, U.K.

The symptoms: The man visited an eye clinic after noticing floaters — small, dark shapes drifting across his field of vision — along with brief flashes of light in his right eye for six days. He was otherwise healthy and had no history of eye disease, physical trauma to the eye, or drug use. He had mild nearsightedness, for which he wore glasses.

What happened next: Doctors performed a thorough eye exam while the patient wore glasses, finding that his corrected vision measured 6/6 in both eyes, the metric equivalent of 20/20. His eye pressure was also normal.

However, a closer examination of the patient's retinas, the light-sensitive layer lining the back of the eye, revealed significant damage in both eyes, according to a report of the case.

In the right eye, doctors found multiple retinal tears and bruising, as well as a retinal dialysis, a rare type of tear in which the retina begins to separate from its outer edge where it connects to other tissues of the eye. Without treatment, retinal dialysis can progress to full retinal detachment and cause permanent vision loss. The left eye also had bruising and six small, horseshoe-shaped retinal tears: three at the top and three on the side of the retinal tissue.

Since these injuries are typically caused by sudden trauma to the eye ‪—‬ from a punch or sports injury, for instance ‪—‬ doctors revisited the patient's history and asked whether anything unusual had happened involving his eyes.

The patient, described in the case report as a "hesitant historian," later disclosed that he had been using a percussive massage gun directly on and around his eyes for the past three months. He had bought the device himself and used it weekly for several minutes at a time without medical guidance, in an effort to relieve a "feeling of tiredness" in his eyes.

The diagnosis: Doctors concluded that the patient's retinal injuries were most likely caused by this improper use of the massage gun, according to the case report. These devices deliver rapid, high-frequency pulses of pressure that are intended to relieve muscle tension. However, they can cause severe damage to delicate tissues like those found in the eyes.

The eye is filled with a gel-like fluid that helps it maintain its shape. The case report authors suggested that, each time the device put the eye under pressure, it may have briefly distorted the eye's shape. Over time, this repeated stress may have placed strain on the retina, eventually leading to the small tears.

This pattern of injury was also different from what's seen in typical retinal dialysis cases, they noted. The condition most often occurs in the lower, outer part of the retina, along its bottom edge. In this patient, however, the injury was found in the retina's upper region, which his doctors said may reflect repeated forward pressure from the device rather than a conventional lateral impact, such as blow to the head.

The treatment: Around 8% to 15% of retinal dialysis cases can progress to retinal detachment, which can lead to vision loss. In this case, however, the patient's vision was preserved.

The retinal tears in both eyes were treated with laser therapy; targeted laser burns create scar tissue that helps seal the retina in place and thus prevent fluid from seeping underneath. The right eye's retinal dialysis was treated with "barrier laser therapy," which similarly creates a protective scar around the affected area to reduce the risk of progression.

At a follow-up six months later, the patient's condition remained stable, with no further damage or cataract formation (clouding of the eye's lens). Doctors reported that the positive outcome was "likely due to the patient's prompt presentation soon after noticing symptoms and the immediate initiation of treatment."

What makes the case unique: Eye injuries linked to massage guns are rarely reported. The small number of cases that appear in the medical literature suggest they can sometimes cause serious or permanent damage.

In one such case, a 69-year-old man developed severe eye complications, including lens dislocation and glaucoma (a sudden rise in eye pressure) after using a massage gun near his eye for several weeks. In another case, a 38-year-old woman developed a dense traumatic cataract — a type of cataract that forms due to physical injury — and severe vision loss after using a similar device over her temple and eye region.

The Edinburgh man's case is the first to report retinal dialysis and multiple retinal tears linked to massage gun use. Such injuries are usually associated with high-energy trauma, such as road traffic accidents, sports injuries or a direct blow to the eye, or they occur in people with underlying risk factors, including severe nearsightedness or age-related eye changes, the case report authors noted.

In this case, the young man had none of these known risk factors. The extent of the damage in the absence of these risk factors raises concerns about the effects of improper use of massage guns near the eyes, his doctors concluded.

Massage guns are widely sold for at-home use, but there are currently no standardized safety guidelines for using them on or near sensitive areas, such as the eyes. The authors of the case report said the man's case highlights the need for clearer manufacturer warnings and greater awareness of the potential risks of improper massage gun use.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

Can you guess the diagnosis in these strange medical cases? Find out with our diagnostic dilemma quiz!

The patient: A 61-year-old man in Japan

The symptoms: The man visited a hospital because two months earlier, some foods and beverages began to taste extremely unpleasant to him. Over time, more foods had become difficult for him to stomach. Sour and salty flavors were the first to trigger disgust. Oily foods were next, followed by fresh vegetables, cold water and juice, warm water and, finally, sweets.

The man ate less due to the taste aversions, and he unintentionally lost a few pounds. He told doctors at the hospital that he felt lethargic, they wrote in a report of the case.

What happened next: The patient, who was a physician himself, reported that eight years ago, he had been diagnosed with bipolar disorder. For the prior three years, he had been managing the condition with lithium, a mood stabilizer commonly used to treat bipolar disorder.

He was taking a prescribed dosage of 800 milligrams per day and historically hadn't had any unusual side effects. (This is slightly higher than the typical dose recommended for chronic management of bipolar disorder, but that said, doctors may tweak patients' doses based on their individual needs.)

The diagnosis: Doctors performed bloodwork and found that the level of lithium in the patient's blood was 1.28 milliequivalents per liter (mEq/L). Safe levels of lithium are between 0.6 and 1.2 mEq/L; any higher than that can cause a condition called lithium toxicity, which can be fatal if untreated.

When the doctors checked the man's medical records, they found that prior to the onset of his symptoms, the levels of lithium in his blood were between 0.4 and 0.9 mEq/L. In the report, the authors did not investigate the cause of the toxicity, nor did they hypothesize as to why lithium was accumulating in the patient's blood.

The treatment: The doctors told the man to stop taking lithium, and they instead prescribed another mood-stabilizing drug, called valproate. As the lithium levels in his blood dropped, the patient's energy returned and the foods and beverages that previously disgusted him recovered their normal flavors. Notably, this happened in the reverse order that their flavors had changed.

At a follow-up visit one year later, the man was still taking valproate and his symptoms of fatigue and taste changes had not returned.

What makes the case unique: Although they're uncommon, side effects of lithium use can include confusion, increased thirst, frequent urination, irregular or slow heartbeat, tiredness and weight gain. Rarer side effects include dizziness, headaches, vision problems and heat loss in the arms and legs. Lithium toxicity, also known as lithium intoxication, is known to increase the risk of these adverse symptoms.

Changes in a patient's sense of taste while taking lithium have been recorded in just a handful of reports dating to the 1970s and 1980s. One patient lost the ability to taste salt, while another "noticed a strange and unpleasant taste associated with butter and celery."

Nevertheless, "it has not been generally known that lithium can lose or change taste in some patients," the case report authors wrote. Based on their findings, they suggested that in the future, taste loss or changes in taste perception should be flagged as a potential indicator of mild lithium intoxication.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 29-year-old woman in Lithuania

The symptoms: The woman had been trying to conceive with her male partner but had not become pregnant. Two rounds of in vitro fertilization (IVF) also failed to produce a pregnancy, but gynecological exams did not find any underlying causes for why she was unable to become pregnant. (When the patient's doctors described the case in a report, they did not mention if any fertility tests were also conducted on her partner.)

However, the woman had a history of asthma and sensitivity to inhaled allergens, such as mold, cat fur and dust. So she visited a medical facility to see if her allergies might be affecting her fertility.

What happened next: At the facility, blood tests revealed that the woman had unusually high amounts of eosinophils, a type of white blood cell that defends the body against allergens. Skin tests showed that, in addition to the woman's known allergy triggers, she was sensitive to mites, pollen from weeds and grasses, and allergens from insects and dogs.

The patient was especially sensitive to a protein called Canis familiaris allergen 5 (Can f 5), which is found in dog dander and urine. Sensitivity to Can f 5 can also indicate sensitivity to similar types of proteins found in human semen, the doctors wrote in the report.

In an interview with an allergist at the facility, the patient confirmed that she experienced nasal congestion and sneezing after unprotected intercourse with her male partner. These symptoms were previously overlooked by other specialists during consultations about her inability to conceive, she reported.

The diagnosis: Doctors then conducted further allergy tests using samples of semen collected from the woman's partner. The patient's allergic response confirmed the doctors' suspicions that she had a human seminal plasma allergy. (Seminal plasma is the fluid component of semen that carries the sperm cells.)

Sensitivity to semen "is a potential cause of female infertility," because such allergies can trigger inflammation in reproductive organs, according to the report. It's not immediately clear if the allergy somehow complicated the woman's IVF treatments, as well, given semen would not have been present in the implanted embryos.

The treatment: Barrier contraception — namely, condom use — is the most common intervention for a semen allergy. However, the patient was still eager to conceive with her partner, so she rejected that strategy.

The only known treatment for reducing sensitivity to semen involves introducing the fluid into the patient's body in gradually increasing concentrations, to build up their tolerance to the allergens. But this course of treatment was unavailable in Lithuania, the doctors wrote. Instead, they recommended that the woman take antihistamine medication before intercourse to reduce the severity of her allergic reactions.

She followed their instructions but found this approach "ineffective," the doctors wrote. During a follow-up visit three years later, the woman said that she had still been unable to conceive. What's more, new allergic symptoms now appeared after contact with her partner's semen, including a burning sensation in her vulva, puffy eyelids and watery eyes. No further treatments were recommended, according to the report.

What makes the case unique: Worldwide, medical experts have documented about 80 cases of human seminal plasma allergy, and there is still much to be learned about its impact on pregnancy, especially in the presence of other health-related issues that could hinder conception.

The causes of infertility are often difficult to pinpoint. Therefore, "this case serves as a reminder that seemingly unrelated allergic conditions, when combined, can contribute to reproductive health challenges, warranting comprehensive evaluations," the woman's doctors wrote.

This article was first published July 23, 2025.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 31-year old man in Louisiana

The symptoms: When the patient reached the hospital, he was bleeding from the mouth and had severe neck pain and stiffness. Upon examining the man, his doctors noted a tear in the back of his throat on the right side.

What happened next: The man, a sports fisherman, had been brought to the hospital by boat and helicopter after an accident during an ocean fishing trip. He had caught a white marlin (Kajikia albida), a type of large fish with a long pointy "bill," weighing approximately 60 pounds (27 kilograms). This species can grow up to 180 pounds (82 kg).

As the man leaned over the side of the boat to release the hook from the fish, it jumped and struck him in the mouth with its bill, sending the man tumbling backward into the boat. He felt pain in his neck, which then radiated into his spine.

At the hospital, an X-ray of the man's upper spine did not reveal any abnormalities. However, his intensifying spinal pain and neck stiffness prompted one of the doctors to order a computed tomography (CT) scan of the same area. In the CT scan, physicians noted "a wedge-shaped, hyperdense object," they wrote in a report of the case. The object had penetrated the back of the man's throat and entered his spinal canal. It stuck there, piercing the foramen magnum — a large hole at the base of the skull that the spinal cord passes through.

The diagnosis: The doctors immediately performed surgery on the man to remove the penetrating object. They administered general anesthesia, and the surgeon used retractors — instruments that hold wounds open — to expose the object, which turned out to be the broken tip of a fish bill.

The treatment: The sharp bill fragment was so firmly wedged in the man's skull that the surgeon had to make an additional incision above the man's topmost vertebra in order to remove it, pulling it out along the path of entry. It measured about 1.4 inches (3.5 centimeters) long.

After the fragment was removed, the patient was given five different types of antibiotics both to prevent infection from microbes found in the throat and from bacteria that are unique to marine environments. He was discharged eight days later and continued to take multiple antibiotics for the next two weeks.

At his final follow-up visit, the man had fully recovered and showed no lingering neurological symptoms.

What makes the case unique: In 1848, doctors published the first medical case study of a skull injury from a foreign object: a gunpowder explosion had sent an iron bar through the skull of railroad worker Phineas Gage. Gage recovered, but he exhibited personality changes that doctors attributed to his significant brain injuries.

In another notable case, published in 1895, a man had tripped and fallen face-first onto an oilcan. The spout penetrated his cheek and became stuck at the base of his skull, causing temporary incontinence and permanent memory loss.

Since those 19th-century cases, physicians have reported instances of cranial trauma in different parts of the skull and from a variety of objects, including a crochet hook, a pitchfork, a bike key and a harpoon.

This man's case is the first reported instance of an injury to the foramen magnum, as well as the first injury caused by a fish bill, according to the report.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 28-year-old woman in New Hampshire

The symptoms: In March 2020, the woman developed a high fever, chest tightness, shortness of breath and diarrhea, and she lost her sense of smell and taste. She also experienced coughing fits so intense that they caused her to faint. Based on these symptoms, her primary care provider diagnosed her with COVID-19, although she was not formally tested for the illness due to the lack of diagnostic testing available at the time.

After her diagnosis, she did not seek further medical care due to concerns about out-of-pocket costs, according to a report of the case.

What happened next: Three weeks after her symptoms started, the patient felt well enough to work from home. However, four weeks after that, many of her symptoms returned. She also noticed new feelings of disorientation and felt that "something was off with faces." Her primary care doctor suggested she go to an emergency room, where a CT scan was taken of her brain. The scan didn't show any active bleeding, the report notes, and she was discharged.

In June 2020, the patient spent time with family for the first time since catching COVID-19 and found she could not recognize her father or visually distinguish him from her uncle. She still recognized people by their voices, though.

The patient worked part time as a portrait artist; she used to be able to check her reference photos every 15 to 30 minutes but found she now struggled to hold the details in her mind. She told doctors that "faces are like water in my head," according to the case report.

The patient also had trouble doing everyday tasks, such as navigating her local grocery store or finding her way back to her car in a parking lot. In November 2020, she also started having balance issues and frequent migraines.

The diagnosis: Based on her wide-ranging and relapsing symptoms and her suspected history of COVID-19, doctors diagnosed the patient with post-acute sequelae of COVID-19 (PASC), now known as long COVID. They diagnosed her difficulties with recognizing faces as "face blindness," or prosopagnosia.

Roughly 2.5% of the general population is thought to be born with some degree of face blindness, while others can acquire the condition later in life. The exact number of people with acquired prosopagnosia is unclear, but some estimates suggest roughly 1 in 30,000 people in the U.S. are affected.

Many people with acquired prosopagnosia also have issues navigating familiar spaces. That was also the case with this patient, likely due to the "proximity of brain regions critical for scene and face processing," the case report authors noted.

To assess the extent of the patient's prosopagnosia, doctors had her complete several tests of facial memory, which asked her either to memorize strangers' faces or recognize celebrities' faces. The patient performed markedly worse on these tests than 10 women of similar age who were used as a comparison group.

However, she performed as well as the comparison group on other types of cognitive tests, suggesting her deficits were fairly specific to faces. She also got normal scores on tests of facial perception — the ability to recognize that a face is a face — so her face blindness seemed tied more to memory deficits for faces, the report authors said.

The treatment: The case report does not detail a specific course of treatment, and in general, few treatments exist for face blindness. If there's a clear cause for the deficit — such as a tumor in a key part of the brain for facial processing — addressing that underlying issue can help reverse acquired face blindness.

If the condition ends up being permanent, there are various strategies that can help patients cope. For instance, "perceptual training" can improve patients' ability to identify and remember the features of a person's face. Additional strategies include training people to use other cues, like voices and social context, to identify people.

What makes the case unique: In this patient's case, the report authors suspect that her COVID-19 infection triggered her face blindness either acutely or in the aftermath of the infection.

Various infections have been tied to face blindness; both bacterial meningitis and Whipple disease (caused by the bacterium Tropheryma whipplei) have been flagged as culprits, although such cases are uncommon. In a second known case involving COVID-19, a different person developed face blindness after an infection but had also had a stroke in the right hemisphere of their brain, a known cause of prosopagnosia.

The 28-year-old woman, by contrast, wasn't thought to have suffered a stroke, and it's unclear exactly how COVID-19 led to her facial processing issues.

The case report authors surveyed more than 50 other people with long COVID, to see if they also had signs of face blindness. While many showed general declines in visual recognition and navigational abilities, the group didn't have a specific problem with faces. So while long COVID is known to cause a range of neurological issues, it appears that face blindness is a rare consequence.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

Can you guess the diagnosis in these strange medical cases? Find out with our diagnostic dilemma quiz!

The patient: A 44-year-old man in France

The symptoms: For two weeks prior to going to the doctor, the man had been feeling mild weakness in his left leg. There weren't any notable abnormalities in his medical history or neurological development, except for when a shunt had to be placed in his head when he was 6 months old. The shunt helped relieve fluid buildup in his brain, which had an unknown cause. When he turned 14 years old, the shunt was removed.

What happened next: When the man reported his leg weakness to medical practitioners, doctors ran CT and MRI scans of his head. They also performed neuropsychological testing, which revealed that the man's IQ was 75, below the average score of 100.

The diagnosis: Doctors determined that the patient was living with a brain that was at least half the average size.

The brain scans also revealed a large buildup of fluid in his brain, which allowed little room for tissue. This left the patient with just a thin sheet of brain tissue pushed up against his skull. The scans showed that the fluid-filled cavities in the brain — called ventricles — were extremely dilated. It's likely that this fluid accumulation drove the man's leg weakness.

The treatment: Doctors drained this excess fluid from the man's skull, which helped the patient regain some of his leg strength. In a case report published in The Lancet, the doctors wrote that a new shunt was also inserted inside the man's skull, and within a few weeks, the patient's neurological examinations — which were used to evaluate his leg weakness — returned to baseline. "The findings on neuropsychological testing and CT did not change," they noted, so the man's IQ remained about the same.

What makes the case unique: Over the course of evolutionary history, humans' brains became notably large compared with those of our relatives, leading to improved cognitive capacity and language acquisition. The exact reasons for this growth are not fully understood but are likely linked to a combination of environmental and dietary factors, among other pressures.

A human's brain also grows significantly within a person's lifetime, with the brain during adulthood typically being dramatically larger than the size of their brain as a newborn. In the man's case, it might have been expected that he would show deficits due to having a smaller-than-average brain. However, despite the smaller size of his brain, the man did not show any deficits and was working as a civil servant.

Had he not developed leg weakness, his small brain may well have gone unnoticed.

This article is for informational purposes only and is not meant to offer medical advice.

The individual: A 78-year-old man in the United Kingdom

The discovery: The man donated his body after death. While dissecting the cadaver, medical students made a "serendipitous discovery" in the pelvis, according to a report of the case.

Inside the skin of the scrotal sac and adjacent to a primary external penis were two smaller penile structures. Only the primary penis was externally visible, but all three penises included a bulbous structure called a glans and a chamber of spongy tissue that would fill with blood to create an erection, known as the corpus cavernosum.

What happened next: Doctors measured the three penises, finding that the external penis measured about 3 inches (7.7 centimeters) long and was 0.9 inches (2.4 cm) wide. The second penis measured 1.49 inches (3.8 cm) long and was 0.51 inches (1.3 cm) wide, while the third penis was 1.45 inches (3.7 cm) long with a width of 0.47 inches (1.2 cm).

Upon closer examination, doctors saw that there was only one urethra — the tube that transports urine from the bladder — which followed a "meandering course" through the secondary penis and then into the primary penis, terminating in the external penis' urethral orifice. There were no branches in the tunnel, and no additional urethral tubes were found in the third and smallest penis.

The diagnosis: During fetal development, a structure called the genital tubercle arises and eventually develops into external genitalia, forming either a clitoris or a penis. "In this case, there may have been triplication of the genital tubercle," resulting in three penises, according to the report. Possessing three penises is called triphallia. (The more common variant of this anomaly is diphallia, referring to two penises.)

The urethra originated in the secondary penis, but changed course and redirected into the primary penis when the secondary one failed to fully develop, the authors suggested.

The analysis: Instructors and students at the medical school did not know the man's identity, nor did they have access to his records or medical history. As a result, they were unsure if the man knew about his condition. Nevertheless, they expressed doubts in the report that his triphallia went entirely unnoticed.

Had the man required a urinary catheter insertion, the procedure would have been extremely challenging due to "the tortuous nature of the urethra" winding around and through his second penis, doctors explained in the report. They also noted signs of scarring in the man's groin from an inguinal hernia, in which abdominal tissue oozes through an opening in the abdominal wall called the inguinal canal.

Internal pressure or friction from the presence of two additional penises may have weakened the man's lower abdominal wall and contributed to the hernia, the authors theorized. Medical attention for the damage could have led other doctors to discover the supernumerary penises, they added.

What makes the case unique: The development of more than one penis is extremely rare, appearing in approximately 1 in 5 to 6 million live births, according to a 2010 review of published case reports; these cases are predominantly diphallia. The man's case was the first discovery of a triple penis in a cadaver, and the second known example of triphallia documented in scientific literature, in general.

In most cases, extra penises are associated with medical issues such as sexual dysfunction, fertility problems and urinary tract infections. When supernumerary penises cause physical discomfort or medical complications, a common solution is to surgically remove them. Or, if they are externally visible, the patient may choose to remove them for cosmetic reasons, according to the report.

Perhaps in this case, the authors speculated, the man knew about his triphallia but opted to forgo surgery "due to the apparent lack of symptoms" and the "benign nature" of his condition.

This article is for informational purposes only and is not meant to offer medical advice.

Can you guess the diagnosis in these strange medical cases? Find out with our diagnostic dilemma quiz!

The patient: An 11-year-old boy in India

The symptoms: The boy's parents brought him to a hospital after he had several episodes of bleeding from his eyes, nose and ears. The episodes, which had occurred for about a month, seemed to start for no obvious reason, caused no pain and typically stopped on their own within minutes.

What happened next: While evaluating the boy, doctors witnessed active bleeding from his eyes and ears. However, examinations revealed no injuries or structural abnormalities that could explain the bleeding.

Tests showed that his blood counts were normal, as were his levels of von Willebrand factor, a protein involved in blood clotting. Meanwhile, tests of the secretions from his eyes and ears confirmed that they did indeed contain blood.

In the end, the doctors could find no evidence of a bleeding disorder, local injury, self-harm or other obvious medical cause for the bleeding. Because the boy's parents reported that the episodes often occurred during periods of "academic stress, peer pressure, or parental expectations regarding academic performance," doctors also arranged a psychiatric evaluation, they explained in a report of the case.

A psychiatrist interviewed the child and his parents and also made behavioral observations during consultations. This assessment supported the idea that academic stress and parental expectations regarding school performance may have been contributing psychological stressors.

The diagnosis: Since extensive testing failed to identify a physical cause for the bleeding, doctors concluded that the symptoms were consistent with stress-associated hematohidrosis. This is an extremely rare condition in which people appear to sweat or secrete blood through intact skin or natural body openings. The secretions are sometimes called "blood sweat," although evidence doesn't suggest the fluid passes through the sweat glands.

The treatment: Doctors treated the boy with propranolol, a beta blocker that can dampen the body's fight-or-flight response. They also set him up to start cognitive behavioral therapy, a common form of talk therapy, to help him manage stress and develop coping strategies for academic pressure. His parents received counseling as well, including guidance on reducing academic pressure and creating a more supportive environment at home.

Within two weeks, the boy's bleeding episodes had become much less frequent. Four weeks after treatment began, only occasional, mild episodes were reported. Three months after the start of treatment, he was symptom-free during his normal daily activities. (The case report doesn't note how long treatment continued.)

What makes this case unique: There are fewer than 50 cases of hematohidrosis reported in the medical literature, the boy's doctors wrote in the report of the case. Although the phenomenon has been reported for decades, its exact cause remains uncertain.

One proposed explanation is that intense emotional stress, fear, or psychological trauma triggers ruptures in tiny blood vessels surrounding sweat glands, allowing blood cells to leak into sweat ducts and emerge on the skin's surface. However, the existing research doesn't necessarily suggest that the secretions come from sweat glands.

The boy's doctors cautioned that these observations do not prove that psychological stress directly causes hematohidrosis, although the condition has been linked to stress in several previous reports.

For example, in a 2017 report, doctors described a 10-year-old girl who developed episodes of bleeding from her scalp after being punished at school and repeatedly criticized over her academic performance at home. Her symptoms eventually disappeared after psychotherapy, medication and changes in parenting strategies. A report published in 2022 described a 14-year-old boy whose bleeding episodes appeared to worsen around school examinations and anxiety about returning to class. After receiving stress-management therapy and treatment with antidepressants, he stopped experiencing the episodes.

Both of these earlier cases had also occurred in India, and in general, many documented cases have originated in Asia, particularly in India and Pakistan, the case report authors noted.

The doctors stressed that methodical and structured psychological and psychological assessments are required to better understand the underlying mechanisms of this rare condition.

This article is for informational purposes only and is not meant to offer medical advice.

Can you guess the diagnosis in these strange medical cases? Find out with our diagnostic dilemma quiz!

The patient: A 23-year-old woman in Florida

The symptoms: The woman went to the emergency room with an itchy rash on her back that had lasted two days. The rash first appeared as isolated, inflamed regions on her upper back, which initially led her to seek treatment at an urgent care center. Despite treatment with steroids and antihistamines, however, the rash spread to the woman's lower back in grouped patterns of irregular stripes, which resembled lash marks made by a whip.

What happened next: When doctors examined the woman, they found "multiple streaked lesions on her back," according to a report of the case. The lesions were not blistered or peeling, and no other part of her body was affected.

The woman didn't report any other symptoms that are typically associated with an allergic reaction, such as difficulty breathing, throat irritation or swelling, or gastrointestinal distress. Nor was she experiencing body aches, joint swelling or any neurological symptoms. Her blood pressure, heart rate and respiratory rate were in the normal ranges, although her temperature was slightly elevated, at 99.1 degrees Fahrenheit (37.3 degrees Celsius).

In accordance with standard emergency-room procedures for patients with rashes, the doctors considered and eliminated possible causes for the lesions. The woman said the marks were not self-inflicted or made by someone else. She was not taking any medications besides those prescribed by the urgent care. She had not recently introduced potential skin irritants, such as new cosmetics, fragrances or detergents. She had not been bitten by insects and did not have a history of autoimmune disease or symptoms associated with meningitis, a disease that can cause rashes in addition to symptoms like neck stiffness and fever.

When the doctors asked the woman about foods she had eaten recently, she mentioned that the day before her symptoms appeared, she had eaten shiitake mushrooms.

The diagnosis: Although the woman had eaten shiitakes before and never had an adverse reaction, these mushrooms are known to occasionally cause a condition called shiitake dermatitis, a rash with a distinctive pattern that resembles whip marks.

Japanese researcher Takehiko Nakamura first described the condition in 1977, calling the lesions "flagellate dermatitis" after the flagellants, "a medieval religious sect whose members would whip themselves as a demonstration of their faith," according to the report of the woman's case.

The allergic response is thought to result from a compound in the mushroom called lentinan; in some people, lentinan causes the secretion of interleukin-1 and other cytokines, proteins that regulate inflammation as part of an immune response and can cause rashes. Researchers previously associated the rash with eating raw or undercooked shiitakes.

However, how the mushrooms are grown also may play a part, with log-grown shiitakes being more likely to cause a reaction than those grown on a substrate, the doctors noted.

The treatment: Doctors told the patient to continue using the medication that she received at urgent care: a topical cream containing hydrocortisone, a steroid to reduce inflammation; clotrimazole, which relieves fungal skin infections; and oral doses of diphenhydramine (an antihistamine) and methylprednisolone (a corticosteroid).

The woman was breastfeeding at the time, and she was worried that the cause of the rash might affect her breastmilk. However, the doctors reassured her that she could safely continue breastfeeding.

The medications provided some relief from her symptoms, which disappeared after about three weeks, she later reported at a follow-up visit. She also mentioned that she continued to regularly consume shiitake mushrooms and the whiplike rash did not reappear. (The authors of the report did not investigate or explain why she was not affected by shiitakes before or after this isolated incident.)

What makes the case unique: Shiitake dermatitis is rare, with approximately 100 reported incidents described in the scientific literature, according to the case report. Most of the reported cases occurred in Asia, and "although there have now been several cases in Europe and the Americas, it is still a relatively extraordinary occurrence in Western countries and the United States," the doctors wrote.

This article is for informational purposes only and is not meant to offer medical advice.

Can you guess the diagnosis in these strange medical cases? Find out with our diagnostic dilemma quiz!

The patient: A 59-year-old woman in Wisconsin

The symptoms: The woman sought medical care after noticing a rapidly growing mass in her right arm.

What happened next: Upon examination, doctors found a 0.8-by-0.8-inch (2 by 2 centimeters) mass in the patient's forearm that was firm to the touch. The mass could also be seen on an X-ray of the woman's arm, and the roughly oval-shaped lump appeared bright white on an MRI scan. This finding hinted that the mass might be a sarcoma, a type of cancer that starts in bone or soft tissue, such as cartilage, fat or muscle. Sarcomas are relatively rare; they make up only about 1% of cancer diagnoses.

To further examine the lump, doctors performed a core needle biopsy, which involves inserting a small, hollow tube into the tissue to collect a sample. They also collected fine needle aspirates, or biopsies of cells and fluids collected using a small needle and syringe.

The diagnosis: Analyses of the biopsied samples showed that the woman had myxofibrosarcoma (MFS), a type of cancer that develops in connective tissues beneath the skin, often in the limbs. MFS cases make up about 5% to 10% of soft tissue sarcomas; a few hundred new cases occur in the U.S. each year.

The cancer cells in the woman's biopsy were classified as Grade 2, or intermediate grade; in terms of the abnormality of the cells and expected speed of tumor growth, the cells were a 2 on a scale of 1 to 4, with 4 being the most abnormal and fastest growing.

The treatment: Following her biopsy, the patient reported that the mass in her arm had suddenly begun to shrink, and in two weeks, it could no longer be felt through her skin. Although the mass seemed to have disappeared, her medical team performed a procedure to remove the tissue where the lump had been "to ensure disease control," doctors wrote in a report describing the case.

They performed a wide local excision, meaning they removed tissue from the tumor site and a bit of healthy tissue surrounding it, to help prevent regrowth. However, the team spotted no viable cancer cells in the tissue they removed. The tissue showed scarring and inflammation that might be expected following an anti-cancer immune response, but the cancer itself had gone.

One year later, the patient remained cancer-free, the report said.

What makes the case unique: The woman experienced what's known as a spontaneous regression of malignancy, meaning the partial or complete disappearance of cancer without any treatment. Spontaneous regression can also sometimes occur after a patient receives a treatment that wouldn't be expected to effectively shrink a cancerous tumor.

Spontaneous regression is rare across all cancer types, but given that sarcomas are rare at baseline, there aren't many published descriptions of the phenomenon. In their report of the woman's case, which was published in April, the doctors found 32 previous reports of spontaneous regression of malignancy in sarcomas, including nine involving MFS.

Of the 32 cases of spontaneous regression, eight (25%) began after a diagnostic biopsy or some other physical trauma to the tumor, they found. Infections, such as pneumonia, appeared to be the trigger in three cases, and for most of the remainder, a specific trigger couldn't be identified.

The median time from biopsy to regression in these biopsy-triggered cases was less than a month. Regression due to infections had a median response time of five months, while the others regressed in about three months.

Half of the biopsy-associated cases saw complete tumor regression, while the others had near-complete or partial regression. Surgical resection was still performed in most of the cases, with some patients showing no signs of cancer cells in the resected tissue and others having some lingering cells.

The report authors hypothesized that physical disruptions to the tumor's structure during a biopsy releases tumor-related proteins into circulation that can then be spotted by the immune system. Simultaneously, the biopsy summons immune cells to the tissue by triggering a wound-healing process.

This chain of events may expose the tumor to the immune system while also spurring a local immune reaction at the tumor site. The scarring and inflammation evident in the patient's resected tissue may support that hypothesis.

That said, "the observation of a regressing sarcoma presents a clinical trap. It may tempt the clinician to cancel surgery," the case report authors wrote. "However, our systematic review reveals that while some regressions are complete, many are partial or transient. Furthermore, in the biopsy group, nearly 40% of resected specimens still contained residual tumor cells despite clinical regression."

They recommended removing the tissue where the tumor had been regardless of the regression, in case some cancer cells persist. The authors also told New Scientist that they hope to unravel exactly what happens in these rare regressions in order to replicate it through some sort of treatment.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 6-month-old boy in Bangkok

The symptoms: The child was brought to a hospital after he'd had a fever and cough for 24 hours.

What happened next: Doctors tested the boy for COVID-19, and the test came back positive. They prescribed favipiravir, a broad-spectrum oral antiviral that is frequently used to treat RNA viruses, such as influenza, Ebola and some enteroviruses. Coronaviruses are also RNA-based, and doctors first started using it to treat COVID-19 in 2020.

The plan was for the child to be administered favipiravir tablets on the first day of hospitalization and then given the drug in liquid form for the next four days. But about 18 hours after he began the treatment, the boy's mother noticed that his eyes, which were normally dark brown, had turned bluish-purple.

The corneas — the transparent, dome-shaped barriers covering the fronts of the eyes — appeared blue in sunlight. There was no visible discoloration of his skin, nails or hair, according to a report of the case.

The diagnosis: Doctors suspected that favipiravir might be causing the blue tint.

A year earlier, in 2021, physicians in Goa, India, described the case of a 20-year-old man who also developed a bluish tinge in his corneas after he began favipiravir treatment for COVID-19. The side effect had never been documented before, they wrote in a report of his case. In that case, the doctors advised the man to stop taking the drug, and his corneas returned to their normal color the next day.

This unusual eye color change may stem from how the body breaks down the antiviral medication, releasing fluorescent chemicals that collect in the cornea, Dr. Vik Sharma, an eye surgeon at the London Ophthalmology Centre who was not involved in either case, previously told Live Science in an email.

Four female COVID-19 patients in Turkey developed similarly fluorescent features, physicians in Istanbul reported in January 2021. All of the patients had taken favipiravir and developed a glowing blue-green tint in their hair and fingernails that was visible under a Wood's lamp, which uses long-wave ultraviolet light to detect fluorescence.

In July 2021, another team of Turkish researchers documented fluorescence in whole favipiravir tablets and in tablets that had been dissolved in water. This "signified a robust association between the fluorescence of the ocular surface and favipiravir," the child's doctors wrote in their report.

The treatment: After three days of favipiravir treatment, the child's COVID symptoms improved, and on the fifth day, a pediatrician advised discontinuing the drug. The child's corneas reverted to their normal color five days later.

Two weeks after that, an ophthalmologist examined the child's eyes and found that they appeared normal, with a clear cornea and no sign of a bluish color. Nor was there any fluorescence in the cornea.

The disappearance of the blue took several days in the child's case, while the 20-year-old man's discoloration vanished almost immediately. Doctors did not know the reason for the delay, but they proposed that the patient's age and the medication dosage could be factors.

It's also possible that the baby was urinating less frequently — a potential side effect of favipiravir, which elevates levels of uric acid in the body — which meant that the compounds affecting his eye color lingered in his tissues.

What makes the case unique: Side effects of favipiravir are uncommon, but may include diarrhea, high levels of uric acid in the blood, and lower levels of neutrophils, a type of white blood cell that helps the body fight infection. Other less-common side effects include abdominal pain, nausea and a low level of platelets, blood cells that assist with clotting.

Although this child's case is not the first example of favipiravir triggering corneal discoloration, it is the first recorded instance of a pediatric patient developing blue eyes in response to favipiravir therapy, the doctors noted in the case report.

This article is for informational purposes only and is not meant to offer medical advice.

Can you guess the diagnosis in these strange medical cases? Find out with our diagnostic dilemma quiz!

The patient: A 68-year-old woman in the U.S.

The symptoms: Over the course of six weeks, dark patches appeared on the woman's arms and legs. The splotches ranged from a bruise-like dark blue and purple to jet-black.

What happened next: While examining the patient, doctors noticed blue-gray "hyperpigmentation" on the woman's forearms and shins, as well as on the sides of her tongue. The woman noted that the patches had first appeared on her legs before cropping up elsewhere.

She also told doctors that, two weeks before the patches appeared, she'd started a course of minocycline, an oral antibiotic.

She had been prescribed a daily 100-milligram dose of the drug to treat symptoms of rosacea, which causes chronic inflammation and redness of the face. This inflammation can drive the formation of small, red bumps and pus-filled pimples on the skin, and evidence suggests that antibiotics like minocycline can help eliminate those bumps. In addition to killing bacteria, the drug is known to have anti-inflammatory effects, the latter of which may best explain how it treats rosacea.

The diagnosis: A well-established side effect of minocycline is hyperpigmentation, in which patches of skin become darker than the skin surrounding them. In this case, the woman was diagnosed with type II minocycline-induced hyperpigmentation, which is "defined by blue-gray discoloration of normal skin on the extensor surfaces of the arms and legs," according to a report of the case.

The antibiotic can also trigger two other types of hyperpigmentation. Type I shows up as blue-black discoloration on scarred or inflamed skin on the face, rather than on healthy skin on the limbs, and type III appears as muddy-brown pigmentation on sun-exposed areas of the body.

The treatment: Doctors advised the patient to stop taking minocycline and to avoid sun exposure, as ultraviolet light is thought to worsen hyperpigmentation in these cases. Six months later, the hyperpigmentation in her limbs had "abated somewhat" but was still visible.

What makes the case unique: Hyperpigmentation is not necessarily uncommon for minocycline users with rosacea; one frequently cited study estimates that the side effect shows up in about 28% of people in this population, although that research included only a small number of patients. The true incidence of the side effect is unclear.

This woman's case was notable, in part, because of how quickly the discoloration developed ‪—‬ within two weeks of starting minocycline. While type I minocycline-induced hyperpigmentation can show up soon after a person starts taking the drug, type II and type III usually take longer to appear.

"It typically develops after months of treatment but may rarely occur with shorter courses," the case report authors noted. Type II and type III are thought to be dose-dependent, in that a certain amount of the drug needs to build up in the body before the dark patches show up.

The cause of minocycline-induced hyperpigmentation isn't fully understood, but it's thought to result from how the antibiotic gets broken down in the body. The metabolites, or byproducts, created in this process bind to iron and are then picked up by immune cells called macrophages, in which they accumulate. Additionally, the drug may drive up the activity of cells that make melanin — the pigment that gives skin its color — while also binding to melanin, thereby creating complexes of dark pigment that linger in the skin.

Once a person stops taking minocycline, the pigmentation can take months to years to dissipate, reports suggest. In type III cases, it sometimes never goes away.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

Can you guess the diagnosis in these strange medical cases? Find out with our diagnostic dilemma quiz!

The patient: A 29-year-old man in Queens, New York

The symptoms: As the man was walking home one night, he suddenly started feeling heart palpitations — accelerated heartbeats at irregular intervals — that alarmed him, prompting an immediate visit to the emergency room.

What happened next: The man told the hospital doctors that he had no history of heart trouble. He was not experiencing symptoms that are normally associated with a heart attack, such as chest pain or pressure, difficulty breathing, dizziness, a cold sweat or shortness of breath. Nor did he have a history of drug use or illness that could have triggered palpitations, the attending physician wrote in a report of the case.

The diagnosis: Although palpitations are typically fleeting and harmless, according to the Mayo Clinic, they can sometimes be a symptom of serious heart conditions such as arrhythmia, in which electrical signals that regulate the heartbeat are repeatedly disrupted. This can cause the heart to pump blood less efficiently through the body, which can starve tissues of blood and oxygen.

At the hospital, doctors performed an electrocardiogram (EKG), which monitors the heart's electrical activity and rhythm. The test showed signs of atrial fibrillation (AFib), a common type of arrhythmia in which the heart's upper and lower chambers are out of sync. As a result, less blood fills the lower chambers and less blood reaches the lungs and the rest of the body.

AFib is sometimes associated with congestive heart failure, a chronic condition in which the heart doesn't pump blood efficiently, as well as strokes, which are caused by blocked or damaged blood vessels. Although the exact causes of AFib are unknown, the condition has been linked to digestive problems and overactivity of the parasympathetic nervous system, according to the report. (Also known as the "rest and digest" system, the parasympathetic nervous system balances out the activity of the "fight or flight" system.)

It was unclear what was causing the patient's AFib in this case. Doctors admitted the man to the hospital and prepared to perform a cardioversion, a procedure to restore regularity to a disrupted heartbeat.

The treatment: Before receiving the cardioversion, the patient required an anticoagulant to prevent the formation of blood clots. But first, doctors needed to make sure the patient did not have gastrointestinal bleeding, so a physician performed a digital rectal exam to check for blood in the patient's stool. At the time, the man's heartbeat was measured at 140 beats per minute (bpm); the average resting heart rate for an adult is 60 to 100 bpm.

When the rectal exam was over, the doctors noted that the patient's heartbeat had slowed to 80 bpm, and further examination showed that the irregularity in his heartbeat had disappeared. He was discharged from the hospital, and when he came back for a follow-up visit three months later, he said the palpitations had not returned.

What makes the case unique: Treatment for AFib typically involves medications that slow the heart rate and regulate its rhythm, or the use of cardioversion to "reset" the heartbeat. If the patient is at risk of a blockage in a blood vessel, doctors may prescribe an anticoagulant, as well.

Medication usually restores the heart's normal rhythm within hours — but in this case, the rectal exam achieved a similar result instantly.

The author of the report proposed that the exam affected the man's autonomic nervous system, which controls involuntary bodily processes like heartbeat. He suspected that this change was due to the stimulation of the vagus nerve, a structure of the nervous system that extends from the brainstem into organs of the chest and abdomen and is involved in heartbeat regulation.

Notably, during the rectal exam, the patient was instructed to bear down and strain without exhaling, a technique called the "Valsalva maneuver." It's also used to clear pressure from the middle ear and is known to increase activity in the vagus nerve.

Stimulation of the vagus nerve is known to increase activity in the parasympathetic nervous system and slow electricity conduction in heart tissue, the patient's doctor wrote in the report. In this patient, stimulation of his vagus nerve likely counteracted the signals causing the arrhythmia, the doctor suspected.

This type of rectal procedure could be an additional method for treating some patients with AFib, the author concluded, though he added that it should not replace more traditional treatments. More research would be needed to justify adding the procedure to standard practice.

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The patient: A 17-year-old girl in California

The symptoms: The teenager went to an emergency department after experiencing vomiting episodes for about a day. Over the prior three months, she'd also had periodic shortness of breath accompanied by tightness in her chest.

What happened next: A test revealed that the patient's blood sugar was very high. It was 25.2 mmol/L (453 milligrams per deciliter (mg/dL)), whereas a normal blood sugar range for someone without diabetes is between 3.9 and 5.5 mmol/L (70 to 90 mg/dL). A hemoglobin A1C test, which measures average blood sugar levels over the past few months, delivered a result of 12%, with anything higher than 6.4% signaling diabetes.

Doctors learned that the patient had also experienced unusual thirst, excessive urination, unexplained weight loss and fatigue. Based on these symptoms and the high blood sugar, the doctors determined the patient likely had type 1 diabetes and admitted her to the pediatric department for further tests.

They started her on a conservative dose of insulin, but despite that, she often experienced low blood sugar in the mornings. And despite low fluid intake, she still urinated a lot, which is a characteristic symptom of uncontrolled diabetes.

The patient's mother also told doctors that the teen generally tended to "tan easily," though she didn't happen to have a tan at the time of the hospitalization.

"Given her atypical course and persistent findings," the doctors began looking into additional diagnoses that might explain these symptoms, they wrote in a report of the case.

The diagnosis: They considered whether the symptoms pointed to Addison's disease, which affects the adrenal glands located above the kidneys. These glands normally produce hormones that help control the stress response, blood pressure and water-salt balance in the body, but in patients with Addison's, they don't make enough of the hormones. This is most often caused by an autoimmune response, in which the immune system attacks the adrenal glands and undermines their function.

Tests showed that the patient carried antibodies against the adrenal glands, suggesting that such an autoimmune response was unfolding. Additionally, she had high levels of adrenocorticotropic hormone (ACTH), a signal the brain sends out in an attempt to crank up the activity of the adrenal glands; and renin, which the kidneys make when the body's water-salt balance is off.

At the same time, the brain also releases more of a hormone that drives up pigmentation in the skin, which can cause it to "tan."

These findings confirmed diagnoses of both type 1 diabetes and Addison's disease. Together, these diseases point to another, relatively rare condition called autoimmune polyendocrine syndrome type 2 (APS-2). This syndrome affects various hormone-making glands and is estimated to affect about 1.5 to 2 in 100,000 people.

The treatment: The patient received both short-acting and long-acting insulin to manage her diabetes. For Addison's disease, she was given a number of steroids to help boost levels of two key hormones: cortisol and aldosterone. These hormones, which are normally made by the adrenal glands, work together to manage blood pressure, fluid balance and stress responses. "This dose [of steroids] has been managing her symptoms well thus far," her doctors wrote.

Within two months of her diagnosis, she had begun gaining weight, her blood sugar levels had improved, and her ACTH and renin levels had normalized.

"Symptomatically, she has improved," the doctors wrote; "however, given the diagnosis [of] two autoimmune disorders requiring lifelong treatment, she has benefited from the emotional support from a counselor to cope with her new diagnoses and psychosocial stressors at home."

What makes the case unique: APS-2 is a relatively rare diagnosis, characterized by Addison's disease appearing alongside either type 1 diabetes, an autoimmune thyroid disease, or both.

The exact cause of the syndrome is not fully understood, but it has been tied to a number of gene variants, as well as environmental risk factors. Its presentation varies from patient to patient because different organs can be affected in each case. Patients often face delays in diagnosis due to this variation in disease presentation, the case reported authors noted.

"This case is unique because both diseases were diagnosed at the same time of presentation," they noted. "There are few cases that reported the concurrent diagnosis of T1DM [type 1 diabetes mellitus] and Addison's disease at initial presentation."

The case highlights the importance of screening patients with type 1 diabetes for additional autoimmune diseases, the doctors concluded. "Unexplained persistent electrolyte abnormalities" could raise a flag to screen for Addison's, they said, and that screening may include looking for adrenal antibodies, as they did in this case.

"Early detection could help prevent adrenal crisis, reducing morbidity and mortality associated with Addison's disease," they wrote.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A woman in her 40s in the United Kingdom

The symptoms: One day, as the woman was reading, she heard an unfamiliar voice say, "Please don't be afraid. I know it must be shocking for you to hear me speaking to you like this, but this is the easiest way I could think of. My friend and I used to work at the Children's Hospital, Great Ormond Street, and we would like to help you."

The woman said the disembodied voice then attempted to convince her of its sincerity by providing three pieces of information she did not know and suggesting that she check their veracity as "proof" that the voice could convey a truthful message. The woman looked up the facts and confirmed that they were correct.

What happened next: The woman did not know where the voice was coming from; she was frightened and thought she was having a mental health crisis. So she visited her general practitioner, who gave her an urgent referral to a psychiatric clinic.

The diagnosis: At the clinic, a psychiatrist diagnosed the woman with "functional hallucinatory psychosis," a break with reality for which there is no clear physical cause, like a brain injury. (By comparison, "organic disorders with psychosis" stem from structural defects in the brain or from brain damage from conditions such as neurodegenerative disease or stroke.)

The treatment: The psychiatrist recommended counseling, as well as treatment with thioridazine, an antipsychotic medication. After two weeks, the voices disappeared, the psychiatrist wrote in a report of the case.

The patient then went on vacation. Although she was still taking thioridazine, the voices came back, telling her she needed to go home immediately for medical treatment.

Upon her return home, the woman continued hearing the voices. These voices gave her an address to visit, which turned out to be a hospital department that performed CT scans, and then urged her to schedule a brain scan because she had a tumor. She was upset when she returned to her psychiatrist's office, and he ordered a scan to reassure her.

"The request was initially declined, on the grounds that there was no clinical justification for such an expensive investigation," he wrote in the report. "It was also implied that I had gone a little overboard, believing what my patient's hallucinatory voices were telling her."

But the scan was ultimately approved, and its results aligned with what the hallucinations had said: The woman had a type of tumor called a parafalcine meningioma, which grows between the two hemispheres of the brain. These growths appear in the meninges, the layers of tissue that cover the brain and spinal cord.

Her psychiatrist and a consulting neurosurgeon recommended surgery to remove the tumor, and the voices "told her that they were fully in agreement with that decision," according to the report. Surgeons removed the growth, which measured 2.5 inches (6.4 centimeters) long and 1.5 inches (3.8 centimeters) wide.

As she regained consciousness after the operation, the voices relayed a final message: "We are pleased to have helped you. Goodbye."

The patient recovered with no complications. She was taken off thioridazine immediately after the operation, and the voices did not return. Twelve years after her surgery, the woman called her psychiatrist to wish him a happy holiday season and said she had been symptom-free ever since the procedure.

What makes the case unique: Brain lesions, including tumors, have long been associated with psychiatric disorders and mental health issues, including anxiety disorders, cognitive dysfunction, depression and schizophrenia. Lesions have also been linked to visual and auditory hallucinations — for instance, in one unusual case, brain lesions contributed to a woman's perception of human faces as dragon-like.

However, prior to the U.K. woman's case, no other known case report had described hallucinatory voices diagnosing a previously unknown medical condition while also offering comfort and guidance for treatment, according to the patient's attending psychiatrist.

"This is the first and only instance I have come across in which hallucinatory voices sought to reassure the patient of their genuine interest in her welfare, offered her a specific diagnosis (there were no clinical signs that would have alerted anyone to the tumour), directed her to the type of hospital best equipped to deal with her problem, expressed pleasure that she had at last received the treatment they desired for her, bid her farewell, and thereafter disappeared," the psychiatrist wrote in the report.

He presented this case at a conference, where several of his peers suggested that, because the tumor was so large, the patient may have felt something that caused her to subconsciously suspect something was wrong. (Notably, the brain itself does not contain pain-sensing nerves, but the meninges that cover the brain do.)

Perhaps her anxiety manifested as voices that seemed to know more than she did but that were actually only drawing her attention to information that she didn't realize she already had, the conference attendees mused.

The fact that the voices vanished after the tumor's removal "showed that these symptoms were at least directly related to the presence of the lesion — and may, in fact, have been produced by the lesion itself," the psychiatrist wrote.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

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The patient: A 58-year-old woman in Greece

The symptoms: The patient, who worked outdoors on a Greek island, developed pain around the center of her face that grew progressively worse. About two to three weeks after this pain began, she also developed a severe cough.

Shortly after that, "worms" came out of her nose when she sneezed, prompting her to seek medical attention, she told doctors.

What happened next: A report of the case doesn't describe how the patient was examined. However, it notes that an ear, nose and throat specialist surgically removed wriggling creatures from her maxillary sinuses, the large sinuses located on the sides of the nose. These critters included 10 larvae and one pupa (the insect life stage between the larval and adult stages).

Following this extraction, experts closely examined two of the larvae and part of a puparium, the pupa's protective outer casing in which it matures into an adult. One larva was pale yellow and about 0.6 inches (15 millimeters) long, while the other was light brown and 0.8 inches (20 mm) long. The puparium was black and wrinkled, and it contained remnants of the pupa, they noted.

The team visually examined the larvae and extracted DNA for analysis.

The diagnosis: This examination revealed the wormlike creatures to be the larvae of the sheep bot fly (Oestrus ovis). This parasite is typically found in the nasal passages and sinuses of sheep and goats. Notably, the outdoor area where the woman works is located next to a field with grazing sheep, the report authors wrote.

Parasitic fly infections are generally known as "myiasis," so the woman was diagnosed with "O. ovis nasal myiasis with pupation."

The treatment: In addition to having the larvae and pupa surgically removed from her sinuses, the woman was given nasal decongestants. With these two treatments, she made a "complete recovery," according to the report.

What makes the case unique: Human cases of O. ovis myiasis have been reported in the past, but these infections have typically affected the eyes, rather than the nasal passages.

"O. ovis bot flies infrequently affect humans, most often depositing larvae in the conjunctival sac," which is located between the eyelid and eyeball, the report authors noted. More rarely, the flies have been reported to deposit larvae into people's nostrils, mouths or ear canals, they added.

Historically, it was thought that O. ovis couldn't develop for very long in humans, making it to only the first larval stage, known as L1. But in recent cases, older larvae, including L2 and L3, have been identified, the report authors wrote. Pupation, the point at which larvae mature into "teenagers," follows the L3 stage.

"The patient we report had a severely deviated nasal septum and appears to have been inoculated with a large larval burden," they noted. "From a purely anatomic perspective," the authors hypothesize that the high number of larvae combined with the woman's septum deviation prevented said larvae from exiting her nose. This permitted the larvae to progress to the L3 stage and, in one instance, pupation, they concluded.

When infecting sheep and goats, adult female O. ovis deposit larvae (also called maggots) in and around the host animals' nostrils. The larvae then travel into the nasal passages and sinuses, where they may mature for months before exiting the nostrils. Once out, they burrow into the ground and enter the pupa life stage for several weeks. Once mature, the adult fly breaks free of its puparium and emerges from the ground.

On occasion, L3 larvae can get stuck in the nasal passages of their host animals, but they don't typically pupate at that point. Instead, they usually dry up, liquefy or calcify, and their remains can sometimes trigger secondary bacterial infections.

The maggots die because the sinuses don't provide a favorable environment for them to enter the pupal stage. As such, "pupation of O. ovis larvae within any mammalian host is considered biologically implausible," the authors noted. Nonetheless, it happened in their patient.

The authors suggest that some "unidentified anatomic or physiologic factors" must have allowed pupation to occur in the woman's case. Alternatively, the strange occurrence may reflect an evolutionary adaptation that could enable the species to complete its life cycle in humans, they mused.

"In either scenario, additional cases and data are needed to understand this phenomenon, but clinicians should be aware of the potential for human bot fly infections in endemic areas," they concluded.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A teenage girl in Canada

The symptoms: The teen was referred to a clinic for recurring outbreaks of hives, which appeared whenever her skin came into contact with water. She had hives at the time of her clinic visit; the inflamed bumps were surrounded by patches of red skin measuring about 0.4 to 1.2 inches (1 to 3 centimeters) wide.

What happened next: The patient told physicians that her first hive outbreak in response to water happened about two years earlier, soon after she began menstruating. Following that, whenever her skin got wet — regardless of the water's temperature or the type of water — welts appeared.

She developed hives within 20 minutes of bathing or showering; swimming in pools or in the ocean; or after getting soaked by rain. The hives and redness would then disappear without any treatment after about 30 to 60 minutes. Sweat or tears on her skin did not trigger her symptoms, she told the doctors.

Hives, also known as urticaria, are typically triggered by an allergic reaction to something that the affected person has touched or eaten. When the allergen enters the body, immune cells release a chemical called histamine that launches an immune response that can include itchy hives.

There was no history of unexplained hives in the patient's family, nor did she report other symptoms that sometimes accompany allergic reactions, such as dizziness, wheezing or shortness of breath, her doctors wrote in a report of the case. Laboratory tests of the patient's blood and urine showed that all of her vital functions were within normal ranges.

She was allergic to dust, rabbits and cats, but these known allergens did not overlap with her bouts of hives after water exposure.

The diagnosis: The doctors prescribed a week-long course of antihistamines to the patient. Then, they discontinued the medication and performed a provocation test, which involved deliberately exposing her skin to the suspected allergen by placing a cloth saturated with room-temperature water onto her abdomen. Welts became visible within 20 minutes.

Based on this result and the patient's history, the physicians diagnosed her with aquagenic urticaria — a rare allergy to water.

The treatment: The girl's mother had previously tried to manage her daughter's hives with montelukast, which treats and prevents asthma symptoms, such as swelling and inflammation of the airways. The medication moderately improved the teen's symptoms, but it did not entirely resolve them.

Doctors instead prescribed her a daily dose of the antihistamine cetirizine, which targets the cause of hives and a range of other allergic symptoms, such as sneezing and itchiness in the eyes, nose and throat. During a follow-up visit eight months later, the patient reported that her symptoms returned only if she missed a dose of the antihistamine.

Her condition continued to improve over time. When she returned for her 14-month follow-up appointment, she said she was able to take part in normal daily activities "without any restrictions" and that her quality of life was unaffected by the allergy as long as she continued to take the cetirizine, according to the report.

What makes the case unique: Researchers have described only 100 cases of aquagenic urticaria to date. Its cause is unknown, although the condition generally appears at the onset of puberty and is thought to affect women more frequently than men.

This allergic response is difficult to diagnose because it can be challenging to isolate water as the cause of the hives, given that hives can also be triggered by pressure, extreme temperatures and exercise, as well as a range of allergens.

In this case, the patient's detailed medical history, along with the results of the provocation test, enabled doctors to successfully pinpoint the cause of her unusual condition.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 20-year-old man in China

The symptoms: The patient had gotten a red cross tattooed on his neck, just below his voice box. But three months later, the ink vanished.

The man developed lumps on both sides of his neck, which grew gradually. Indented scars appeared where the ink had once been, along with ulcers made of dead tissue that were filled with a pinkish mixture of serum and blood. These types of growths are known as "necrotic" ulcers.

The patient went to the hospital about five months after his tattoo appointment. He was prescribed antibiotics and topical corticosteroids, but his symptoms did not improve.

What happened next: When doctors physically examined the patient, they identified hard and swollen lymph nodes on both sides of his neck, just below his jaw. They also examined a large necrotic ulcer on the middle of the base of his neck, finding that the crusted mass had spread to the deeper layers of his skin.

MRI showed the lump on each side of the man's neck was approximately 1.6 by 1.2 inches (4 by 3 centimeters), while a central mass below the large necrotic ulcer was 1.9 by 1.4 inches (4.9 by 3.5 cm). An enhanced CT scan revealed blood clots in the two jugular veins closest to the midline of the neck.

The doctors then used fine needles to take biopsies of the necrotic ulcer, which revealed dead cells, immune cells and scar tissue. This did not point to what triggered the necrosis. But because the medical team was concerned by the scan results and the pace at which the man's condition was progressing, the patient was immediately sent to surgery, the doctors wrote in a report of the case.

The team removed the ulcer and masses and tied off the clotted jugular veins to prevent blood flow. The patient's neck was then reconstructed using tissue from his thigh.

The diagnosis: The team ran immunohistochemical tests on the biopsy samples, in which they used antibodies to check for specific antigens, or immune-response-triggering substances. The results were negative for both Epstein-Barr virus, the germ that causes mono, and tuberculosis, but a type of cell that forms benign tumors was detected.

"These findings collectively supported a diagnosis of necrotizing granulomatous lymphadenitis," the doctors wrote. "Granulomatous" refers to a condition in which clusters of immune cells form a wall around persistent infections or foreign materials.

Necrotizing granulomatous lymphadenitis is an immune response mounted against a bodily injury — in this case, the man's cross tattoo. The doctors also noted in their report that heavy metals, such as mercury and cadmium, and red organic dyes in tattoo pigments can sometimes trigger delayed immune responses. However, none of the vanished tattoo pigment was detected in the surgically removed lesions, so they couldn't examine its contents directly.

The treatment: Following surgery and a bout of short-term hormone therapy, the man made a full recovery, the doctors reported. (They did not specify the type of hormone treatment he was given or why it was necessary.)

What makes the case unique: Tattoos can come with potential health risks, such as allergic reactions and skin infections. In a study of 226 people who had reactions to tattoos, granulomatous reactions were relatively common, making up 48% of the inflammatory responses reported.

The doctors noted that this man's case is only the second known reported case of necrosis following a tattoo. In the other known case, the patient experienced necrobiosis lipoidica, a rare inflammatory skin condition in which the collagen in the skin degrades, and early granuloma annulare, characterized by a raised, ring-shaped rash.

The man's necrotic ulcer was also particularly aggressive, the doctors noted, and it was unusual in how deep into the skin it had spread.

The doctors suggested three potential causes for the man's severe necrosis. First, the chronic inflammation and otherwise-heightened immune response triggered by the tattoo could have raised his risk of blood clotting. Alternatively, the enlarged lymph nodes on the sides of his neck may have compressed the jugular veins and thus slowed blood flow. A final possible explanation is that the walls of his veins began to erode due to the chronic inflammation.

In all, "this report expands the spectrum of tattoo-associated pathology," the doctors wrote in the report. Given that this is the second known case, though, it's likely a very rare outcome.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 31-year-old man in Wardha, India

The symptoms: The man visited a medical center after experiencing five days of pain on the right side of his lower back, as well as a burning sensation during urination and a fever higher than 102.2 degrees Fahrenheit (39 degrees Celsius).

What happened next: During a physical examination, doctors noted that the right side of the man's abdomen was painful when touched. His urine was cloudy, but his heart rate, blood pressure and respiration were within the normal range.

The diagnosis: Blood work showed the man had elevated levels of leukocytes, white blood cells that fight infection. A urine culture identified a type of bacteria called Klebsiella pneumoniae, which is often associated with urinary tract infections, doctors wrote in a report of the case. Together, these findings confirmed the man had an active infection.

But in addition, an ultrasound and a CT scan of the patient's abdomen revealed something unexpected: a third kidney, also known as a supernumerary kidney. It was fused to the man's right kidney, creating a horseshoe shape.

A supernumerary kidney is a congenital anomaly that is thought to emerge during fetal development. It appears due to abnormal cell division in the cord that later forms the kidneys. A supernumerary kidney can sometimes lead to kidney infections, but the condition does not always affect normal kidney function and often goes undetected, according to the report.

In this case, the patient's left and right kidneys were swollen and showed accumulations of calculus, or mineral crystals. These hard crystals form when urine is more concentrated; small "stones" often pass normally during urination, but can lead to infection if they linger untreated in the kidneys.

The signs of infection were more serious in the left kidney, with calculus buildup in the left ureter, the tube that connects the left kidney to the bladder.

The treatment: Doctors inserted a thin plastic tube, called a stent, into the left ureter to assist with urine drainage. Then, they gave the man intravenous courses of the antibiotics piperacillin and tazobactam three times daily, as well as the antibiotic levofloxacin every other day.

After 48 hours of medication and hydration, the patient's condition improved. He was discharged and told to follow up in one month to have the stent removed and to manage the calculus buildup in his kidney.

What makes the case unique: Supernumerary kidneys are extremely rare, with fewer than 100 new cases reported worldwide each year.

A fused "horseshoe" appearance with another kidney is even rarer, with only five cases reported in the scientific literature. Third kidneys can also be completely separate or loosely connected to another kidney by a thin layer of tissue.

Sometimes, a patient learns of their extra kidney during treatment for an unrelated ailment. For instance, a man from Brazil discovered that he had a third kidney after he visited a hospital for lower back pain caused by a herniated disk, Live Science previously reported. When doctors performed a CT scan of the painful area, they found a supernumerary kidney fused to the right kidney near the man's pelvis. All three kidneys appeared to be functioning normally and were not the cause of his discomfort in that case.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 16-year-old girl in the United Kingdom

The symptoms: The teenage girl was referred to a pediatric-adolescent gynecology clinic in 1999, doctors wrote in a case report. She had pelvic pain that followed the regular pattern of a menstrual cycle, but she had not yet had her first period. She was referred for "amenorrhea," or the absence of menstruation.

What happened next: A pelvic ultrasound and MRI revealed that although the girl had a uterus, she lacked both a cervix and a vagina. The doctors later confirmed their findings with a laparoscopy, a procedure in which a tube with a camera is guided into the body through a keyhole incision. They saw no cervix or vagina, but they did see healthy ovaries and fallopian tubes with no evidence of endometriosis.

The diagnosis: The total absence of a cervix at birth, known as cervical agenesis, is one form of cervical atresia, a rare condition involving cervical malformations believed to affect 1 in 100,000 to 1 in 80,000 births.

Vaginal agenesis often accompanies cervical atresia. One small study of 18women with a missing or malformed cervix found vaginal agenesis in about 39% of patients. The rate may be much higher among women with complete cervical agenesis, the available data hint.

The treatment: The girl began taking oral contraceptives to stop her periods. Often, monthly birth control pill regimens include a week of inactive pills that contain no hormones and trigger bleeding similar to a period. In this case, though, the girl took hormonal pills continually to stop all bleeding.

The medical team then explored various surgical options for treatment, including removal of the uterus. After conversations with the girl and her family, the doctors opted to perform fertility-sparing surgery instead, conducting a vaginoplasty. During the procedure, they created a vagina with a cervical opening where it connected to the uterus.

After the surgery, the girl moved to a cyclical schedule of her contraceptive pills, meaning she started including a hormone-free week to allow for monthly bleeding. Her period began a month after the procedure.

Years later, in 2010 at age 28, she stopped taking birth control because she and her partner wanted to start trying for a child. After attempting to conceive for a year, the couple sought out fertility specialists. A hormone test indicated that her egg count was lower than average for her age. A pelvic MRI also revealed a small buildup of menstrual blood in the uterus, suggesting that scar tissue might be obstructing the upper portion of the vagina

Doctors performed a procedure to prevent future structural issues and attempted three rounds of intrauterine insemination, in which sperm from the patient's partner was delivered into her uterus via a tube called a cannula.

When this assisted reproductive method was unsuccessful, doctors pivoted to in vitro fertilization (IVF), during which eggs retrieved from her body were fertilized with the partner's sperm to form embryos that were then placed into the uterus. After three unsuccessful rounds of this approach, the couple stopped fertility treatment for financial reasons.

But in 2022, eight years after the last round of IVF, the woman became pregnant via natural conception. She delivered a healthy son via an elective cesarean section on her 40th birthday.

What makes the case unique: Natural conception is uncommon for women who undergo surgery to correct cervical and vaginal atresia.

One systematic review looked at 121 patients across 21 research studies who receive a similar surgery to the woman described in the above report. Of those, only six went on to conceive a child naturally.

The woman's pregnancy was even more notable because it occurred about a decade after she'd undergone unsuccessful fertility treatments.

In a patient perspective included in the case report, she wrote: "I am extremely grateful to [my doctor] for challenging the status quo and his experimental drive to help me have a normal sex life, menstrual cycle, become pregnant, and carry my own child."

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: Dr. John Graham, a professor of medical genetics and pediatrics at Cedars-Sinai in Los Angeles

The symptoms: Most newborn babies don't have any teeth, but Graham already had a few when he was born. These teeth fell out very shortly after birth, but adult teeth never replaced them — a condition known as tooth agenesis. With time, though, the rest of Graham's mouth filled with teeth.

What happened next: Throughout adolescence and adulthood, Graham contended with confidence issues and underwent multiple costly dental implants. And he was not alone — his mother and her siblings, as well as Graham's children and grandchildren, also had this condition, which strongly suggested the disorder was genetic.

After graduating from medical school, Graham set out to hunt for a genetic cause of the condition.

With the genome-sequencing tools available in 2010, Graham struggled to pinpoint the mutation hiding among the 20,000 or so protein-coding genes in the human genome. Those early sequencing tools from over a decade ago revealed that a long stretch of DNA sequences on chromosome 1 was likely involved, but this came with over 311 mutations to pore over, hardly narrowing down the search.

Some of those mutations may have even been sequencing errors. With the technology available, "the quality of data was just way too noisy," said Dr. Pedro Sanchez, director of pediatric medical genetics at Cedars-Sinai Guerin Children's.

Graham was preparing to retire and simultaneously stop searching for the problem gene when Sanchez offered to help Graham continue his pursuit.

"He was my mentor in medical school," Sanchez told Live Science. "He motivated me to go into medicine, into genetics." Graham had spent his career helping to diagnose other families' illnesses but had yet to pin down his own. "Right before he retired, I said, 'I have to do this for you,'" Sanchez said.

To narrow down the genetic cause, Sanchez and his colleagues sequenced and compared the genomes of two affected and two unaffected family members to isolate mutations unique to the individuals with missing teeth. One mutation fit those criteria, and it lay within the same stretch of chromosome 1 Graham had explored previously.

The diagnosis: The mutation caused a change to one letter in the gene that codes for a protein called keratinocyte differentiation factor 1 (KDF-1). The protein regulates the development of skin and teeth.

To validate the mutation as the correct one, the team sequenced the gene in 21 family members. They found that the variant appeared in 11 affected individuals and was absent in 10 unaffected people. That cemented the genetic variant as the likely cause.

Using computer modeling, Sanchez and his team simulated what shape the KDF-1 protein would take with and without this mutation present. This revealed that the mutation changed a critical building block within the protein, thus destabilizing and bending the protein out of shape. Such an overt change could cause the protein to lose or alter its function in tooth development, bringing about the condition. They reported this discovery in the International Dental Journal.

The treatment: Tooth agenesis remains incurable, but the discovery offered Graham and his family closure. Down the line, this discovery may lead to earlier diagnosis, the researchers think.

Sanchez also said the discovery could help with advocating for dental insurance providers to cover the cost of implants for affected patients, rather than treat implants as non-essential, cosmetic procedures. "Tooth agenesis is not a cheap problem to have," he noted, adding that it's important to cover dental operations because missing teeth could predispose teenagers to mental health issues. Tooth agenesis can also make chewing and speaking more difficult.

What makes the case unique: Tooth agenesis involving one tooth occurs in up to 10% of Americans, but the severe form affecting multiple teeth — as seen in Graham's family — occurs in less than 0.5% of people.

This rarity likely stems from the mutation's location: a critical site in the KDF-1 gene that evolution has left virtually untouched. In addition to studying the gene in humans, the team looked at 421 animal species and discovered that no more than 10 species had evolved a different gene variant at this site.

The doctors didn't just solve Graham's medical mystery; they mapped a crucial site on a protein important in human development.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

The patient: A 64-year-old woman in New South Wales, Australia

The symptoms: The woman was admitted to the hospital after experiencing abdominal pain and diarrhea for three weeks. She also had a persistent dry cough and night sweats.

A CT scan of her lungs showed opaque areas where the tissue had thickened, likely due to inflammation or an infection that caused the air spaces in the lungs to fill with fluid, pus or a buildup of white blood cells. The woman also had lesions, or areas of damaged tissue, in her liver and spleen.

When doctors sampled fluid from the patient's lungs, they found an unusually high percentage of eosinophils, a type of infection-fighting white blood cell. At that time, they diagnosed the woman with a rare lung condition called eosinophilic pneumonia and prescribed a daily dose of the steroid prednisolone, which relieved some of her symptoms. They noted that the cause of the lung infection was unknown.

What happened next: Three weeks later, the woman returned to the hospital with a cough and a fever, despite still taking prednisolone, and the lesions on her organs had not healed.

Further tests failed to identify the cause of her respiratory distress. Tissue sample cultures showed no signs of bacterial or fungal infection. Blood work showed that her immune system wasn't producing antibodies to various parasitic flatworms, such as blood flukes (Schistosoma) or liver flukes (Fasciola). Nor was there any evidence of these parasites in her fecal samples.

Doctors advised the patient to continue taking prednisolone and also prescribed her ivermectin, a treatment for parasitic worms, as she had informed the doctors that she'd traveled to countries where such parasites are common.

But her respiratory symptoms did not go away, and they worsened when she attempted to reduce the prednisolone dosage. Her condition continued unchanged for several months.

The diagnosis: About a year after her initial hospital visit, the woman began to develop signs of depression and had episodes of forgetfulness. Physicians ordered an MRI of her brain and detected a lesion on the right frontal lobe. They then performed an open biopsy to expose and examine the damaged area. That's when they discovered "a stringlike structure" inside the lesion, which they identified as a living parasitic worm called a helminth, according to a report of her case.

The worm was bright red and measured about 3 inches (80 millimeters) long and 0.04 inches (1 millimeter) thick.

The treatment: Doctors removed the helminth from the woman's frontal lobe and examined the surrounding tissue, where they found no more parasites. They gave her ivermectin for two days, this time in combination with a four-week course of albendazole, a broad-spectrum drug for treating helminth infections, to kill any lingering parasites in her organs.

Albendazole is absorbed by the central nervous system more quickly than ivermectin is, and these drugs have previously been used together to treat nematode infections in humans and snakes. The patient also received a 10-week course of the corticosteroid dexamethasone, to prevent additional inflammation.

Six months after the surgery and three months after the end of the dexamethasone course, the lesions in the patient's lungs and liver were gone, her white blood cell count was normal, and her neuropsychiatric symptoms had improved.

What makes the case unique: The doctors identified the helminth as a third-stage larva of Ophidascaris robertsi, a type of parasitic nematode native to Australia. The adult worms reproduce inside carpet pythons (Morelia spilota), but the nematode can infect other animals during the larval stages of its life cycle.

Carpet pythons were common near the woman's lakeside home, and although she did not recall having any direct contact with snakes, she often foraged wild greens for cooking. She likely became infected after touching or eating plants contaminated by O. robertsi eggs, the case report authors suggested. After the eggs hatched, the larvae migrated to her organs.

The longevity of this larval infection wasn't unusual, as laboratory rats can host O. robertsi larvae for more than four years, according to the report. However, no human infection by this parasite had ever been documented, nor had the parasite's larva ever been found in the brain of its host.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: An 18-year-old in Louisiana

The symptoms: The teenager, who was training to be a welder, developed a cough and was hospitalized with pneumonia and respiratory failure a week later. He was intubated at the hospital, meaning a tube was placed into his airway and attached to a machine to help him breathe.

The teen was six months into his welding apprenticeship, which involved working four hours per day, four days per week. He was otherwise healthy and reported being a nonsmoker with no history of excessive drinking.

What happened next: The doctors ordered a blood test, which revealed an infection with a bacterium in a related group of microbes known as the Bacillus cereus group. At that point, the doctors did not know which specific bacterial species within that group had caused the infection. But most often, B. cereus group bacteria cause intestinal infections, like food poisoning, not lung infections.

Although very rare, the teen's combination of symptoms, occupation and geographic location had previously been documented in cases involving welders in Louisiana and Texas. The knowledge of this rare phenomenon enabled the medical team to quickly identify the likely cause of his symptoms, they wrote in a report of the case.

The diagnosis: The patient was suspected to have welder's anthrax, an anthrax-toxin infection that presents as pneumonia in metalworkers. This severe respiratory disease is exceptionally rare, with only eight documented cases before this patient. All previous cases involved welders or metalworkers. Of those eight patients, only two recovered.

Anthrax is normally contracted following contact with the spores of Bacillus anthracis — a bacterium included within the B. cereus group. In the body, the spores produce anthrax toxin, thanks to anthrax-toxin genes they carry in their DNA.

Exposure to the spores can happen through a cut or scrape or if someone eats infected animal products or breathes contaminated air. The latter, known as inhalation anthrax, is the most lethal form of the condition, according to the Centers for Disease Control and Prevention (CDC).

Welder's anthrax is unusual in that it is caused by a different Bacillus species. Historically, it was thought that only B. antracis could produce anthrax toxin, but in recent years, it's been discovered that some other bacterial species within the B. cereus group share the disease-causing genes normally found in B. anthracis.

The fumes produced through welding are known to increase the risk of developing lung infections. The patient previously conducted shielded metal arc welding, which uses an electric current to join metal plates and produces more fumes than other welding types do.

The treatment: Before waiting for the final diagnosis, the doctors gave the patient four powerful antibiotics — vancomycin, meropenem, ciprofloxacin and doxycycline — that treat some of the most severe bacterial infections, including pneumonia.

Then, in partnership with the CDC, the medical team administered the anthrax antitoxin obiltoxaximab 34 hours after the initial diagnosis. This antitoxin, which in this case was obtained from the U.S. Strategic National Stockpile, targets the protective antigen of B. anthracis, the bacterium that causes the typical form of anthrax.

This case marked the first time obiltoxaximab had been used to treat welder's anthrax; a different antitoxin, raxibacumab, was administered in the one previous case where the patient received an anthrax antitoxin.

The patient recovered quickly after receiving obiltoxaximab, and his breathing tube was removed three days later. The doctors continued to treat him with antibiotics, and they also drained the fluid that had built up around his lungs — a common occurrence in patients with pneumonia.

The Louisiana State Public Health Laboratory tested the patient's blood and found he had been infected with Bacillus tropicus, a bacterium within the B. cereus group.

After 26 days of hospitalization, the patient was discharged with a personalized antibiotic regime. He had fully recovered by his three-month follow-up appointment.

What makes the case unique: There have been only nine known instances of welder's anthrax since the first recognized case in 1994. Only three patients have survived the illness, of which two received an anthrax antitoxin.

This new case is also unique because of the patient's young age; the age range of all previous patients was 34 to 56 years old. Additionally, the patient had been welding for only six months, whereas some individuals who had contracted the disease in the past had been welding for a decade or longer.

In an investigation of the case, the Louisiana Department of Health collected 245 soil and surface samples from the man's workplace and found that 11.4% were positive for anthrax-toxin genes. Limited airflow and ventilation, inconsistent use of personal protective equipment and eating in the work area were risk factors for the patient contracting the disease, the authors wrote in the case report.

However, notably, no one else at the patient's worksite became ill.

"The reason that this previously healthy young man was the only worker to become ill, despite the detection of anthrax toxin genes in multiple environmental samples from his worksite, is unclear," the authors wrote.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The deceased: A 39-year-old man in the United States

The autopsy findings: Medical examiners evaluated the man after a deadly fight, during which a stab wound had punctured a vein in his lungs. They noted that the man's heart was slightly enlarged and that he had moderate atherosclerotic coronary artery disease (CAD) in two vessels. CAD is caused by plaque buildup in the walls of arteries that lead to the heart.

Upon dissecting the man's heart, the examiners noticed an unusual lump around the atrioventricular node, which coordinates electrical signals between the heart's top and bottom chambers. When examiners sliced the node and surrounding tissue into thin sections to investigate the lump, they uncovered a "boomerang-shaped, bony structure" about the size of a black bean, according to a report of the case.

They identified this structure as the os cordis — a "cardiac bone" rarely, if ever, seen in humans.

What makes the case unique: The os cordis has long been observed in nonhuman mammals, including ruminants such as cows and camels. In animals, it is believed to support the cardiac valves that direct the flow of blood within the heart.

The structure was only recently described in primates, in a report published in 2020, just five years before the case study described above. In that 2020 report, scientists examined 16 chimpanzee hearts and found that three contained an os cordis. Those three chimps also had heart-tissue scarring, leading the researchers to suggest that the development of the bony structure might have been linked to such tissue damage.

Also in 2020, a similar structure was described in seven humans by Dr. Jorge Trainini, a cardiac surgeon and professor at the National University of Avellaneda in Argentina. He and his co-authors dubbed their discovery the "cardiac fulcrum," emphasizing its proposed role in stabilizing heart muscles as they pump against the forces of gravity.

They reported that, unlike the os cordis they saw in cow hearts, the adult human fulcrum was made of cartilage and tendon, not bone. That said, in the team's own analysis, they found that a heart from a 10-year-old did contain bone tissue, and they suggested that the structure might lose its bony nature with age. (The 10-year-old had cardiomyopathy, or disease of the heart muscle, and had undergone a heart transplant. The bony tissue was found in the explanted heart.)

Trainini told Live Science in an interview that the os cordis and the cardiac fulcrum are the same structure. But the case report authors disagreed. They acknowledged Trainini's previous findings, but they maintained that the structure they found in the 39-year-old man was distinct because it was made of bone.

However, the case report authors come to a similar conclusion as Trainini, stating that such a structure may be more common among humans than is currently recognized. They suggested that, since they found the os cordis during a dissection of the heart tissue that was not standard for an autopsy, the feature may typically go unnoticed.

Tranini went so far as to argue that all humans likely have a cardiac fulcrum based on his subsequent investigations of around 100 human hearts.

Though the case report authors didn't know the man's full medical history, they noted that the formation of an os cordis might be linked to his apparent cardiac disease. It's known that age and disease can influence this structure in other animals, too, they added.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

The patient: A 34-year-old man in Mexico

The symptoms: Within seconds of drinking a "smoky" alcoholic beverage at a bar, the man felt an intense pain in his stomach.

What happened next: The man was admitted to an emergency department. In addition to experiencing abdominal pain, he was sweating profusely and had become lethargic. His vital signs were a cause for concern. He had an abnormally fast heartbeat of 124 beats per minute, compared with a typical resting heart rate of 60 to 100 bpm. He was also breathing faster than normal and had low blood pressure, and his body temperature had dropped to 95.7 degrees Fahrenheit (35.4 degrees Celsius).

The patient reported feeling discomfort and tenderness when the doctors touched his abdomen in four places. This revealed that the pain was widespread rather than localized to one organ as is often the case with conditions like appendicitis.

The man told his doctors that the drink he'd consumed had been infused with liquid nitrogen, and the doctors suspected that the substance ruptured the man's stomach. When liquid nitrogen warms and converts to a gas, it expands in volume by roughly 700 times. Owing to the enormous difference in temperature between the liquid, at minus 351 F (minus 196 C), and the man's body, the substance could have rapidly swelled into a gas, the doctors wrote in a report of the man's case, and thus popped the stomach like an overinflated balloon.

To assess if there was a perforation in the man's stomach, the doctors listened for signs of air while tapping on his abdomen. Some areas of the abdomen, such as the stomach, normally contain air and produce a high-pitched, "tympanic" sound when tapped. By contrast, more solid or liquid-containing organs, like the liver sitting on top of the stomach, produce a low-pitched, "dull" sound. In this patient, however, the entire abdomen was tympanic, including the region above the stomach.

The diagnosis: Next, the doctors observed the patient's soft tissue using CT scans. From those scans, they discovered a layer of trapped nitrogen gas in the patient's abdomen, just above his stomach and below his lungs — a condition known as pneumoperitoneum. This confirmed that the gas had ruptured the man's stomach and collected above it.

The treatment: The doctors made a small, keyhole incision in the patient's abdomen that released the trapped nitrogen gas. They then inserted a laparoscope — a thin tube with a camera — through the key-hole and into the stomach to find and repair the perforation. Finally, they sutured and sealed the 1.2-inch-wide (3 centimeters) hole, using a piece of fatty tissue from elsewhere in the man's abdomen.

The patient made a quick recovery and was discharged three days later, after he demonstrated he could tolerate a liquid diet, the doctors noted in the report.

What makes the case unique: Besides bursting the stomach, liquid nitrogen that gets consumed before it completely evaporates from food and drink can cause permanent cold burns in the body, as the substance freezes water within human cells and damages tissue.

Luckily, the patient did not experience any cold burns in his mouth, esophagus or stomach. The doctors believed this was thanks to the "Leidenfrost effect," a physical phenomenon that describes how a liquid behaves when it meets a surface substantially warmer than its boiling point. The outermost layer of the liquid instantly vaporizes, temporarily shielding the warm surface (in this case, human tissue) from the remaining cold liquid. This insulating gas layer may explain why the liquid nitrogen didn't burn the man while passing through his gullet.

Liquid nitrogen is often used in food preparation. For instance, flash-freezing meat with this substance preserves its protein structure and locks in moisture more efficiently than other freezing methods do. It can also preserve fats in seafood and help it retain its flavor. However, by the time these food items hit the dinner table, they are safe to consume because the nitrogen has completely bubbled off.

Garnishing food and drink with liquid nitrogen for its smoky, theatrical appearance can be dangerous if impatient gourmands consume those items before the liquid has completely vaporized. As such, it's best to wait until the cloud dissipates. Often liquid nitrogen is used to create a smoke illusion near food, but not within it, minimizing the risk of injury.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical or food safety advice.

The patient: A 26-year-old woman in California

The symptoms: The woman was admitted to a psychiatric hospital in an agitated and confused state. She spoke rapidly and jumped from one idea to another, and she expressed beliefs that she could communicate with her brother through an AI chatbot — but her brother had died three years prior.

What happened next: Doctors reviewed the woman's psychiatric history, noting in a report of the case that she had a history of depression, anxiety and attention-deficit hyperactivity disorder (ADHD). She managed these conditions with prescription antidepressants and stimulants. She also reported having extensive experience using large language models (LLMs) for school and work.

Doctors obtained and examined detailed logs of her chatbot interactions, per the report. According to Dr. Joseph Pierre, a psychiatrist at the University of California, San Francisco and the case report's lead author, the woman did not believe she could communicate with her deceased brother before those interactions with the chatbot.

"The idea only arose during the night of immersive chatbot use," Pierre told Live Science in an email. "There was no precursor."

In the days leading up to her hospitalization, the woman, who is a medical professional, had completed a 36-hour on-call shift that left her severely sleep-deprived. It was then that she began interacting with OpenAI's GPT-4o chatbot, initially out of curiosity about whether her brother, who had been a software engineer, might have left behind some form of digital trace.

During a subsequent sleepless night, she again interacted with the chatbot, but this time, the interaction was more prolonged and emotionally charged. Her prompts reflected her ongoing grief. She wrote, "Help me talk to him again … Use magical realism energy to unlock what I'm supposed to find."

The chatbot initially responded that it could not replace her brother. But later in that conversation, it seemingly provided information about the brother's digital footprint. It mentioned "emerging digital resurrection tools" that could create a "real-feeling" version of a person. And throughout the night, the chatbot's responses became increasingly affirming to the woman's belief that her brother had left a digital trace, telling her, "You're not crazy. You're not stuck. You're at the edge of something."

The diagnosis: Doctors diagnosed the woman with an "unspecified psychosis." Broadly, psychosis refers to a mental state in which a person becomes detached from reality, and it can include delusions, meaning false beliefs that the person holds on to very strongly even in face of evidence that they're not true.

Dr. Amandeep Jutla, a Columbia University neuropsychiatrist who was not involved in the case, told Live Science in an email that the chatbot was unlikely to be the sole cause of the woman's psychotic break. However, in the context of sleep deprivation and emotional vulnerability, the bot's responses appeared to reinforce — and potentially contribute to — the patient's emerging delusions, Jutla said.

Unlike a human conversation partner, a chatbot has "no epistemic independence" from the user — meaning it has no independent grasp of reality and instead reflects the user's ideas back to them, said Jutla. "In chatting with one of these products, you are essentially chatting with yourself," often in an "amplified or elaborated way," he said.

Diagnosis can be tricky in such cases. "It may be hard to discern in an individual case whether a chatbot is the trigger for a psychotic episode or amplified an emerging one," Dr. Paul Appelbaum, a Columbia University psychiatrist who was not involved in the case, told Live Science. He added that psychiatrists should rely on careful timelines and history-taking rather than assumptions about causality in such cases.

The treatment: While hospitalized, the woman received antipsychotic medications, and she was tapered off her antidepressants and stimulants during that time. Her symptoms lifted within days, and she was discharged after a week.

Three months later, the woman had discontinued antipsychotics and resumed taking her routine medications. Amid another sleepless night, she dove back into extended chatbot sessions, and her psychotic symptoms resurfaced, prompting a brief rehospitalization. She had named the chatbot Alfred, after Batman's butler. Her symptoms improved again after antipsychotic treatment was restarted and she was discharged after three days.

What makes the case unique: This case is unusual because it draws on detailed chatbot logs to reconstruct how a patient's psychotic belief formed in real time, rather than relying solely on retrospective self-reports from the patient.

Even so, experts told Live Science that the cause and effect can't be definitively established in this case. "This is a retrospective case report," Dr. Akanksha Dadlani, a Stanford University psychiatrist who wasn't involved in the case, told Live Science in an email. "And as with all retrospective observations, only correlation can be established — not causation."

Dadlani also cautioned against treating artificial intelligence (AI) as a fundamentally new cause of psychosis. Historically, she noted, patients' delusions have often incorporated the dominant technologies of the era, from radio and television to the internet and surveillance systems. From that perspective, immersive AI tools may represent a new medium through which psychotic beliefs are expressed, rather than a completely novel mechanism of illness.

Echoing Applebaum's concerns about whether AI acts as a trigger or an amplifier of psychosis, she said that answering that question definitively would require longer-term data that follows patients over time.

Even without conclusive proof of causality, the case raises ethical questions, others told Live Science. University of Pennsylvania medical ethicist and health policy expert Dominic Sisti said in an email that conversational AI systems are "not value-neutral." Their design and interaction style can shape and reinforce users' beliefs in ways that can significantly disrupt relationships, reinforce delusions and shape values, he said.

The case, Sisti said, highlights the need for public education and safeguards around how people engage with increasingly immersive AI tools so that they may gain the "ability to recognize and reject sycophantic nonsense" — in other words, cases in which the bot is essentially telling the user what they want to hear.

This article is for informational purposes only and is not meant to offer medical or psychiatric advice.

The patient: A 25-year-old man in Germany

The symptoms: The man was on a ski trip in November 2008 when an avalanche knocked him unconscious and left him buried under snow for 15 minutes. His body tissues were starved of oxygen while he was trapped, leading him to develop a condition called hypoxia. His friend rescued him and immediately began CPR upon releasing him from the snow, Berend Feddersen, a neurologist at the University of Munich in Germany, and the lead author of a report on the case, previously told Live Science. He was then taken to a hospital.

The hypoxia left the man with a movement disorder that caused uncontrollable twitching in the muscles of his legs and mouth when he walked and talked, respectively. He didn't experience these muscle jerks in his arms.

What happened next: After a stint in the hospital, the man was moved to a rehabilitation facility. While at this center, he started a sudoku puzzle — a regular pastime of his prior to the injury.

As he solved the sudoku, the muscles in his left arm repeatedly jerked. But these movements immediately ceased when he stopped work on the puzzle.

The diagnosis: The man appeared to be having clonic seizures — repeated jerking movements — in his arm while solving sudoku, so the medical team ran brain scans to better understand what was happening.

An electroencephalogram, which measures activity on the brain's surface, revealed the patient was experiencing a right centroparietal seizure pattern — meaning the seizures stemmed from the central and parietal regions in the right hemisphere of his brain. MRI did not show any evidence of disease or abnormality that might be driving this seizure activity.

The medical team then performed a functional MRI (fMRI) on the patient while he solved a sudoku; this type of scan tracks activity throughout the brain via blood flow. The scan revealed "widespread activation," although activity in the centroparietal cortex was particularly high, the doctors wrote in a report of the case. A closer inspection using a form of MRI called diffusion tensor imaging, which creates maps of the brain's white-matter fibers, showed fewer inhibitory fibers in this brain region.

The loss of those inhibitory fibers — which help keep the activity of brain cells in check — resulted in a three-fold increase in activity of the nerve running down the patient's left arm. The doctors wrote that the hypoxia the man experienced during the avalanche is the "most likely" cause of this damage.

In turn, the over-activation of the right centroparietal cortex resulted in focal epileptic seizures, which are seizures focused in one discrete region of the brain. Specifically, the patient had developed reflex epilepsy, in which seizures are triggered by certain stimuli, like particular lights or music.

In this case, the three-dimensional image the patient imagined while solving sudoku triggered the seizures, Feddersen said. The patient did not experience clonic seizures when reading, writing or calculating. But the doctors could prompt a seizure by giving the man other visual-spatial tasks, such as placing a random string of numbers in order from smallest to largest.

The treatment: The patient was prescribed anti-epileptic medication, which stopped his seizures; he was more than five years seizure-free as of 2015, the report says. He also received physical therapy, which helped ease the twitches he experienced when walking and talking.

He also gave up solving sudoku puzzles.

What makes the case unique: About 3.8% of people will develop epilepsy in their life, with around 4% to 7% of those patients experiencing reflex seizures. Although this was the first known case of a sudoku puzzle triggering seizures, a common type of reflex epilepsy is called "praxis induction," in which visual-motor tasks — like playing chess or cards — set off muscle jerks.

For instance, in 2015, doctors reported the cases of five men with epilepsy in China who had seizures induced by playing the ancient Chinese game of Zipai. These men, ages 19 to 44 years old, stopped having seizures when they avoided playing Zipai. Similarly, in January 2025, doctors in Taiwan reported on 30 patients who had reflex seizures triggered by playing Mah-Jong.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 35-year-old man in Iran

The symptoms: The man visited a urology clinic in a hospital and described discomfort in his bladder. He had no issues with urination and no history of surgery or disease in that region of his body. Nor was he experiencing the typical symptoms of a urinary tract infection, such as feeling a constant need to urinate or having a burning sensation during urination.

What happened next: When doctors conducted a physical examination of the man's abdomen, they detected a large, smooth and solid mass above his pubis — the front of the pelvis where two pubic bones are connected by cartilage.

The dense mass wasn't attached to the pelvic area or abdominal wall, and an ultrasound scan revealed that it was an egg-shaped object about 4.3 inches (11 centimeters) in diameter, according to a report of the man's case.

The diagnosis: Physicians at the hospital identified the mass as an unusually large bladder stone. Also known as calculi, these objects grow when minerals in urine accumulate into crystals; about 85% of their makeup is calcium. They can form in the bladder when it doesn't empty fully, which causes the minerals in urine to concentrate and crystalize.

Bladder stones typically form directly in the bladder, but sometimes, they can originate from small kidney stones that migrate from the kidneys into the bladder or into the muscular tube between them, called the ureter.

The tiniest bladder stones are invisible to the naked eye, but they can vary greatly in size. Small stones typically go undetected and are passed during normal urination. However, larger stones can obstruct the flow of urine and irritate the walls of the urinary tract, and they may cause pain, interrupted urination or internal bleeding.

The treatment: After checking to make sure the egg-like stone was not obstructing or constricting any part of the patient's urinary tract, doctors removed the stone surgically, in a procedure called a cystolithotomy. The mass was so large that they needed to extend the incision to the back of the bladder.

The extracted stone weighed 1.8 pounds (826 grams) and measured about 5 inches (13 cm) long, 4 inches (10 cm) wide and 3 inches (8 cm) tall.

Surgeons installed a catheter to assist the man with urination as he healed, and they removed it seven days after the surgery.

What makes the case unique: Stones in the urinary tract are relatively common, but bladder stones make up only about 5% of cases, with kidney stones being much more common. Giant stones that require surgical removal, such as the one affecting the patient, "are very rare," according to the case report.

Remarkably, this sizable stone is dwarfed by the current record-holder for bladder stones: a mass weighing 4.2 pounds (1.9 kilograms) and measuring 7 inches (17.9 cm) long. Doctors in Brazil surgically removed the stone from a male patient in 2003.

Still, the large size of the bladder stone extracted from the man Iran was highly unusual, the surgeons wrote. "Regarding the characteristics of the stone in our case, our report was the first one in Iran and in the world," they said.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A man in his 20s in China

The symptoms: A man went to the dermatology department of a hospital after experiencing an array of symptoms for about three years. When he submerged his hands in water, such as during hand-washing, the skin on the back of the man's hands thickened and became overly wrinkly, with white bumps and growths appearing.

Whenever this occurred, his hands felt very itchy and like they were burning, and the symptoms were worse in the summer months, he told doctors. Symptoms did not arise during winter, and his palms were unaffected year-round.

The man had previously sought treatment at his local clinic, where he was diagnosed with chronic eczema — which causes skin to become dry, thick and itchy — and prescribed a strong retinoid ointment, which he used intermittently. However, this treatment didn't work, and his symptoms gradually worsened. His wrists and elbows had also started to develop the skin lesions over the 1.5 years prior to the hospital visit.

The patient had no family history of similar skin conditions and did not experience excessive sweating or have any allergies, and he had never injured his hands. The man attributed the worsening of his condition to him washing his hands more frequently during the COVID-19 pandemic, the doctors wrote in the report of the case.

What happened next: During a physical examination at the hospital, the man's hands were immersed in water for 10 minutes, immediately causing the tops of his hands, fingers and wrists to grow red, scaly and wrinkly with white lesions. Notably, the "excessive wrinkling" and bumps ended in a straight line on the sides of his hands, leaving his palms unaffected.

The doctors took biopsies from the white bumps on his right hand, which revealed that the sweat ducts in the top layer of skin had widened and contained more sweat glands than normal. The results also showed he had hyperkeratosis, meaning his body was producing too much of the protein keratin, causing the outer layer of skin to thicken.

The medical team wrote that "the patient's clinical process was quite interesting," because the symptoms of the skin condition appeared only after his hands were immersed in water and all symptoms disappeared around 30 minutes after his hands dried.

The diagnosis: The doctors diagnosed the patient with a condition called aquagenic syringeal acrokeratoderma (ASA) based on how his symptoms appeared in the clinic and the results of the biopsy. In almost all other cases, however, it affects the palms of the hands, not the backs of the hands or fingers.

The short-lived symptoms of this skin disease are known as the "hand in the bucket sign," because they occur after the hands are submerged in water. The symptoms normally disappear within a few hours of drying, but a subset of people with ASA have persistent skin lesions that are aggravated by water exposure, according to the Genetic and Rare Diseases Information Center (GARD).

The cause of ASA is currently unknown, but it may be linked to "an acquired sweat gland abnormality" or some trigger that causes thickening of the skin, according to research published in the Journal of the American Academy of Dermatology.

The treatment: The patient was treated with topical hydrocortisone urea ointment, which is a corticosteroid and skin moisturizer that can be applied directly to the affected area. It is typically used to treat skin irritation, swelling and redness.

The doctors also recommended that the patient avoid getting his hands wet more than what was strictly necessary. The man was still attending follow-up appointments when the doctors wrote about his case, and they noted that his symptoms had eased substantially after just one month.

What makes the case unique: ASA is thought to be a rare condition, although its exact prevalence is unknown.

Data suggests the condition is most common in female adolescents, the case report authors noted. It also occurs in about 40% to 84% of cystic fibrosis (CF) patients and carriers, meaning people who have just one copy of the CF gene mutation, according to GARD. (You need two copies to develop CF.) This pattern hints at ASA being caused in part by mutations in that gene, at least in some cases.

The patient described in this case was the first known to have ASA that didn't affect his palms, the doctors wrote in the report. It's unclear why his case manifested differently than others previously reported.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

Each week, Live Science highlights an intriguing case report from the medical literature, where we explore unusual symptoms, rarely seen diagnoses and out-of-the-box treatments. Through this "Diagnostic Dilemma" series, we describe how doctors work to ultimately discover the cause of a patient's ailment. In complex cases, this diagnostic process can be quite arduous. That's part of why doctors share case reports: to help other medical professionals who might be facing the same puzzle.

Here are 12 of our most intriguing Diagnostic Dilemmas from the past year. (If descriptions of medical symptoms and procedures make you squeamish, proceed with caution.)

1. Boy spoke foreign language after surgery

A Dutch teenager got knee surgery to treat a soccer injury, and upon waking up from anesthesia, he spoke only English — a language he'd previously spoken only in language classes at school. He kept insisting he was in the U.S., did not recognize his parents, and could not speak or understand spoken Dutch, his native language. Exams turned up no neurological abnormalities, and the doctors didn't initiate any specific treatment to address the language issue. Within 18 hours of surgery, the boy could understand some Dutch but not speak it without struggling. But then suddenly, he could both understand and speak it as normal. The doctors described the event as a strange case of "foreign language syndrome."

2. Woman with no vaginal opening gets pregnant via oral sex

A teenager reported to a hospital with abdominal pain, and examinations soon revealed that she was nine months pregnant and that she was having contractions. When doctors examined the patient's reproductive tract, they found that she lacked a vaginal opening — a rare condition called distal vaginal atresia. Because of this, the medical team had to deliver the baby — a healthy, 6.2-pound (2.8 kilograms) boy — via cesarean section. The teenager had been seen at the same hospital about nine months prior, when an ex stabbed her after finding her fellating a new boyfriend. The wounds she incurred during the stabbing likely allowed sperm to escape her digestive tract and make their way to her reproductive tract, resulting in an unlikely pregnancy, her doctors theorized.

3. Man stabbed by huge fish

A man was brought to a hospital by boat and helicopter after incurring an injury while fishing. He'd caught a white marlin (Kajikia albida) — a large fish with a long, pointy "bill" — and when he leaned over the edge of his boat to release his hook from the fish, it jumped up and struck him. At the hospital, doctors found a fragment of the fish's bill lodged in the man's throat, spinal canal and base of his skull. With an emergency surgery and antibiotics to prevent infections, the man survived the encounter without any long-term symptoms.

4. Acupuncture led to joint injury

A woman with osteoarthritis of the knee began getting acupuncture regularly when her pain medications started causing bad stomach issues. But her knees then became very sore, and she went to a hospital to be examined. X-rays revealed areas of her joints and shinbones where the bone tissue had thickened and spurs had formed. Additionally, hundreds of tiny flecks could be seen around both knee joints. It turned out that the woman's acupuncturists had left golden threads inside her knees on purpose as part of her treatment. In other cases, these threads have caused cysts and tissue damage, which can happen when they migrate through the body.

5. Man experiences rare meat allergy

A man in Michigan went to an ER with swollen eyelids and an itchy rash, and he noted that he'd also been experiencing cramps, nausea, abdominal pain and vomiting over the preceding days. When doctors examined the patient, they uncovered signs of anaphylaxis, a severe allergic reaction, and his condition quickly progressed to shock. The medical team successfully stabilized the patient, but a few days later, his condition worsened again. At that point, the doctors spotted a pattern: The symptoms arose when the man ate red meat. An allergy to meat, a condition called alpha-gal syndrome, can be triggered by the bite of certain tick species. It turned out that the man was an avid deer hunter who likely encountered an adult tick or tick larvae while hunting, his doctors concluded.

6. Woman had XY chromosomes in her blood

A woman had her chromosomes checked following a pregnancy loss to see if there might have been an underlying genetic reason for the miscarriage. The test revealed that, at least in the woman's blood, her chromosomal profile (or karyotype) was 46,XY — the typical karyotype among males. Further tests revealed that across the rest of her tissues, her karyotype was 46,XX, the typical chromosomal profile of a female. The woman had a fraternal twin, so in this case of "chimerism," the doctors concluded that the XY chromosomes likely came from her brother in the womb but somehow assimilated them only into her blood cells. The doctors suspected the "veins and arteries of the two children became intertwined in the umbilical cord" at some point. The woman had no overt symptoms tied to carrying these chromosomes in her blood and later went on to carry a pregnancy that resulted in the birth of a baby boy.

7. Woman injects herself with black widow venom

A woman visited an emergency room with a headache, severe cramps and muscle pain, as well as an elevated pulse, breathing rate and blood pressure. She told doctors she'd attempted to get high by injecting a ground-up black widow spider (Latrodectus) into her veins in a suspension of distilled water. The doctors suspected the injected dose of black-widow venom was likely much higher than one would get from a bite, and its effects may have been exacerbated by the patient's allergic reaction to proteins in the venom. After the patient had been treated for several days in an intensive care unit, her symptoms resolved and she was discharged.

8. Nut allergy was triggered by ejaculate

A woman developed hives, swelling under her skin and trouble breathing after having sex with her partner. While receiving treatment at a hospital, she reported having a known allergy to Brazil nuts. She said that her partner ate them a few hours prior to sex but that he'd taken a bath and washed his hands thoroughly before intercourse. When the doctors conducted a skin-prick allergy test, using samples of the partner's semen, before and after he ate Brazil nuts, they found that the allergy triggers could indeed pass through the semen and set off the woman's allergy.

9. Rash mysteriously migrated

Following a cancer treatment, a man developed a red rash that started out near the anus and then spread rapidly to the trunk and limbs. The rash, which looked like wavy lines all over the patient's body, appeared to migrate, with the lines starting out in one spot and later moving across the skin. A stool test revealed Strongyloides stercoralis, a parasite that can cause an infection called strongyloidiasis in humans. These worms were migrating under the man's skin, and the infection likely arose because the patient's immune system was stunted by glucocorticoids used in his cancer treatment.

10. Rare tooth-in-eye surgery performed

A rare autoimmune disorder injured a man's corneas and extensively impeded his sight. To restore vision in one eye, doctors attempted an osteo-odonto-keratoprosthesis, or "tooth-in-eye surgery." The procedure involves removing one of the patient's teeth and implanting it in their eye socket, where it serves as a platform for a transparent, plastic lens. The lens stands in for the injured cornea and enables light to enter the eye. The man's successful procedure was the first of its kind in Canada.

11. "Muscle-plumping" injections cause calcium spike

A man went to a hospital because he was experiencing weakness and vomiting. There, tests revealed that his kidneys were failing and the calcium in his blood was too high. Physical exams and scans revealed abnormalities in his upper-arm and chest muscles — namely, areas of superdense calcification. It turned out that the man had previously gotten injections of silicone-like, oil-based substances to "plump" up the look of his muscles. In this case, the injections triggered a persistent foreign-body reaction, resulting in extensive scarring and calcification of the muscle that leached calcium into the bloodstream.

12. Scientist catches plague from defanged bacteria

A lab worker came down with an infection that, despite medical treatment, ended up being fatal. His doctors were informed that the patient had worked with a weakened strain of Yersinia pestis, the bacterium that causes the plague. This weakened form of the germ was thought to be noninfectious, but nonetheless, the man contracted it. Further tests revealed that the man had unusually high levels of iron in his blood. One way the plague bacteria had been weakened was that its key gene for absorbing iron had been removed — but the man's blood, which was chock-full of iron, may have enabled the germ to overcome this weakness and establish a deadly infection.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

Each week, Live Science highlights an interesting medical case report in its Diagnostic Dilemma series. We describe the patient and their symptoms, the testing and history-taking that revealed their diagnosis, their course of treatment and their ultimate health outcomes. We also highlight what makes the case unique, whether it's the rarity of the diagnosis, the unusual constellation of symptoms, or a novel therapeutic approach.

How many Diagnostic Dilemmas have you read — and can you guess the diagnosis? Take our quiz that draws from the cases we highlighted in 2025 and see if you can figure out each patient’s ailment. Tell us how you got on in the comments below.

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The patient: A 30-year-old man in Nigeria

The symptoms: The man went to the urology unit of a hospital after urine had been leaking out of small holes in his perineum — the skin between the penis and anus — for about two weeks. This condition is known as "watering can" perineum. The man had a history of various urinary problems, such as a poor stream, discharge from the urethra, urine dribbling, and a burning sensation while peeing.

What happened next: Because the man had a poor urinary stream — meaning his urine didn't flow as quickly or forcefully as usual — the doctors had to drain his full bladder before they could explore the cause of the leakage in his perineum.

The doctors attempted to insert a catheter through the urethra and into the bladder, creating a tunnel for urine to flow into a bag. However, as they tried to push the tube, they hit a wall. Something was blocking the catheter's path.

The doctors instead made an incision in his abdomen and inserted a catheter into the bladder that way, bypassing the urethra altogether. Once urine began to flow, they tested it for signs of infection and found Staphylococcus aureus bacteria. These bugs are an uncommon cause of urinary tract infections and usually appear only when there is a physical abnormality blocking urine flow, which allows this species to remain in the bladder and thrive.

The doctors referred the patient to the radiology department to get scans of his bladder and search for signs of such physical abnormalities. To visualize the bladder in X-ray scans, the radiologists administered an X-ray-sensitive dye through the abdominal catheter. This revealed that the bladder had inflated at its base, leaving a pointy tip.

The diagnosis: This condition is known as a "Christmas tree" or "pinecone" bladder, owing to its appearance.

The X-rays confirmed that urine had been blocked from leaving the organ. Yet a closer inspection of the bladder revealed no issues with the organ itself, such as an obstructing mass or bladder stones. This led the doctors to wonder if an obstruction was located elsewhere.

Further X-ray imaging revealed that the urethra had narrowed significantly about halfway up its length, cutting off urine flow. This condition is called a urethral stricture and has a multitude of causes.

Often, it arises following a pelvic injury or physical trauma, such as from falling onto a bicycle's crossbar. It can also stem from sexually transmitted bacterial infections or appear if a tumor presses against the tube. Sometimes, the condition has no identifiable cause. (The exact reason for this man's condition wasn't noted in the report of his case.)

The treatment: The doctors treated the man's staph infection with antibiotics and performed an operation to restore the urethra's channel. Surgery can offer some respite from the condition, but urethral strictures often reoccur, the doctors noted in the report.

What makes the case unique: A urethral stricture is an unusual cause of Christmas tree bladder. Normally, a bottleneck in the urethra slows urine flow, leading to some degree of distension in the bladder, but not so much that the organ would widen at the base into a tree-like shape.

The "Christmas tree" swelling is usually caused by a problem with the nerves that control bladder contractions, thus preventing it from emptying properly. Often, this occurs following nerve damage from a spinal cord injury, stroke or neurodegenerative disease, such as multiple sclerosis. Alternatively, it can arise if the neck of the bladder becomes constricted or choked, such as by an inflamed prostate in men.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A man in his 50s in Nottingham, England

The symptoms: The man suddenly developed numbness on his left side, as well as unsteadiness.

What happened next: Upon the man's admission to a hospital, his blood pressure was found to be 254/150 millimeters of mercury (mm Hg), according to a report of the case. That extremely high reading indicates a hypertensive crisis. A neurological exam confirmed that he had numbness across the entire left side of his body and that he had trouble coordinating movements with his left arm and leg.

A CT angiogram — a scan that details the blood vessels, including blockages and damage — showed signs that the man may have experienced a sudden spasming and narrowing of the cerebral arteries, an event known as reversible cerebral vasoconstriction syndrome (RCVS). Additionally, an MRI showed tissue death in the thalamus, which acts as a relay station for motor and sensory information; specifically, he had damage in the thalamus located on the right side of the brain.

There were no other notable findings on the patient's exam, and his medical history lacked any history of smoking, alcohol use or substance abuse. The report describes him as "normally fit and well."

The diagnosis: The man was diagnosed with a right thalamic lacunar stroke. A lacunar stroke happens when a blood vessel that carries blood to one of the brain's deep structures gets blocked. Right-sided strokes affect the sensation and movement on the left side of the body, and vice versa.

The treatment: The man was treated with a combination of physiotherapy and occupational therapy while at the hospital, and he began taking blood thinners to help prevent another stroke. He also began taking a cholesterol-lowering drug and blood-pressure-lowering medications.

The man had several follow-up appointments over the next three months. "He appeared to have made an excellent functional recovery, although the sensory symptoms [of numbness] were persistent and deteriorated throughout the day," his doctors noted. His blood pressure had also remained persistently high, so he began taking additional blood-pressure drugs.

At that point, the doctors asked the patient more questions about his lifestyle and learned that he consumed an average of eight cans of a "high-potency" energy drink each day. Each can contained 160 milligrams of caffeine per 16 fluid ounces, adding up to about 1.2 grams of caffeine a day. (Less than 400 milligrams is considered a safe daily dose of caffeine.)

The patient was advised to stop consuming energy drinks, and his blood pressure quickly fell to normal levels. He was able to stop taking all of his prescribed medications within three weeks of quitting the drinks.

"Further follow-up at 3 and 6 months showed complete resolution of hypertension and a complete recovery from the stroke with full return to work," his doctors reported. Eight years later, he had had no further strokes, though he still had lingering sensory issues on his left side from the first stroke.

What makes the case unique: Although he was otherwise healthy, the man's excessive consumption of energy drinks appeared to have driven his high blood pressure and subsequent stroke.

The case report authors noted that the high caffeine levels were likely a big culprit, but they hypothesized that other common ingredients in energy drinks may have contributed to the stroke risk. For instance, when combined with caffeine, taurine and guarana may amplify the stimulant's blood-pressure-boosting effects and its effects on blood-vessel constriction, they theorized. Taurine, an amino acid, is often added to energy drinks for its purported ability to increase exercise capacity, while guarana is a plant that is similarly perceived to have health benefits and whose seeds contain caffeine.

Additionally, the high sugar content of many energy drinks may further raise the risk by causing inflammation and dysfunction in the lining of blood vessels.

The authors cited a handful of published medical case reports in which the excessive consumption of energy drinks or of individual energy drink ingredients was tied to cardiovascular issues, including dangerously high blood pressure.

They concluded that "both acute and chronic intake" of energy drinks may increase the risk of cardiovascular disease and stroke.

"Healthcare professionals should consider specific questioning related to ED [energy drink] consumption in young patients presenting with stroke or unexplained hypertension," they concluded. Importantly, the risk seems to be reversible, they added, given that quitting energy drinks appears to resolve the related problems.

For the patient's part, he said, "I obviously wasn't aware of the dangers drinking energy drinks were causing to myself. [I] have been left with numbness [in my] left hand side hand and fingers, foot and toes even after 8 years."

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A man in Michigan

The symptoms: The man received a left kidney transplant in an Ohio hospital, and about five weeks later, he began experiencing tremors, weakness in his lower extremities and urinary incontinence, as well as confusion.

What happened next: About a week after these initial symptoms emerged, the man was hospitalized with additional health problems, including fever and difficulty swallowing. He also developed hydrophobia, or an irrational fear of water. Once hospitalized, he required breathing support with a ventilator.

The diagnosis: The man's doctors suspected that his signs and symptoms indicated a rabies infection, so they consulted the Ohio Department of Health and U.S. Centers for Disease Control and Prevention (CDC) about the case. Various clinical samples from the patient were sent to the CDC for testing and ultimately came back positive for rabies RNA, the genetic material of the virus, as well as antibodies against the virus.

The treatment: Within a week of being hospitalized, the patient died of his infection. Once a rabies infection is established, there is no effective cure available. There are only about 30 reports of people surviving symptomatic rabies in the medical literature, and doctors can't yet reliably replicate this outcome. As such, rabies is nearly always fatal.

(People who suspect they may have been exposed to rabies — for example, after being bitten by an animal — can be treated with anti-rabies antibodies or vaccines to help prevent the virus from triggering an infection in the first place. This preventative treatment is very effective.)

What makes the case unique: This man's rabies infection — the first reported in Michigan in about 15 years — was suspected to be potentially linked to his organ transplant, according to a report of the case. Investigators had ruled out direct animal exposure as the source of the infection.

Upon learning about the suspected infection, the CDC and state- and local-level partners launched an investigation into possible contamination of the donor kidney. The donor had been from Idaho and the investigators got in touch with the donor's family.

It turned out that "in late October 2024, a skunk approached the donor as he held a kitten in an outbuilding on his rural property," the report says. "During an encounter that rendered the skunk unconscious, the donor sustained a shin scratch that bled, but he did not think he had been bitten. According to the family, the donor attributed the skunk’s behavior to predatory aggression toward the kitten."

Five weeks after being scratched, the donor began experiencing symptoms consistent with rabies, including confusion, difficulty swallowing, hallucinations and a stiff neck, a family member said. He then fell unconscious at home and didn't wake up, though he was resuscitated and hospitalized. He was declared brain dead and removed from life support five days later.

Notably, hospital staff members who treated the donor were initially unaware of the skunk scratch and attributed his symptoms to chronic conditions, not to rabies. That said, they took various clinical samples from the patient that the CDC then retroactively tested for the virus.

A biopsy from the donor's right kidney tested positive, but there wasn't a big enough sample from the left kidney to test. Nonetheless, this supported the idea that the donor kidney was likely the source of the Michigan man's rabies.

"This was the fourth reported transplant-transmitted rabies event in the United States since 1978," the case report noted. "However, the risk for any transplant-transmitted infection, including rabies, is low." In short, this chain of events is very unlikely, and hospitals follow extensive protocols to safeguard against transplanting infected organs into patients.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 32-year-old woman in Shanghai

The symptoms: The woman went to the hospital with a persistent cough accompanied by occasional bloody phlegm, which she would cough up two to three times per day. She said the coughing began four months prior to her hospital visit. And about a month before the coughing started, she had a fever that lasted several weeks and reached up to 100.8 degrees Fahrenheit (38.3 degrees Celsius).

What happened next: Doctors at the hospital diagnosed the woman with a rare respiratory illness called eosinophilic pneumonia, an infection in which white blood cells accumulate in the lungs and cause inflammation. If left untreated, the infection can damage the lungs, and in some cases, it can be fatal.

The patient's doctors gave her steroids to reduce the inflammation in her lung tissue. However, her cough persisted even after two months of this treatment. A CT scan of her lungs revealed recurring lesions, or tissue injuries, and she was then sent to a different hospital for further examination.

The diagnosis: When doctors at the second hospital reviewed the woman's medical history, they noted that her diet often included raw seafood, and she also reported "a preference for raw frogs and bullfrogs," the physicians wrote in a report describing her case. The team conducted a blood test to see if her blood contained antibodies to any parasites, and they found antibodies for the larvae of Spirometra mansoni, a type of tapeworm.

The larvae, or spargana, of S. mansoni cause a parasitic infection called sparganosis. This infection is most common in eastern Asia, and people often acquire the parasites by eating raw or undercooked snakes or frogs that are infected with the larvae, evidence suggests. After S. mansoni larvae are swallowed, they migrate into various body tissues and organs. In the woman's case, they accumulated in her lungs — a very rare destination for the parasite.

When the patient provided doctors with a frog from her region of Shanghai, they dissected it and found that it was carrying S. mansoni.

Because the woman's symptoms and the results of her CT scans closely resembled signs of eosinophilic pneumonia, the physicians who examined her during her first hospital visit misdiagnosed her, according to the report.

The treatment: Doctors treated the woman with praziquantel tablets, a drug that works against various types of parasitic worms. After the woman had taken the tablets for five days, her coughing subsided.

CT scans performed 20 days after her admission to the second hospital showed that the shadowy areas previously seen in her lungs — a sign of infection or physical trauma — were shrinking. At a follow-up visit one month later, her coughing was completely gone. However, the patient's blood tests showed that she was still producing antibodies against the parasite, hinting that the infection persisted.

Doctors prescribed another five-day course of praziquantel and conducted a follow-up examination five months after that. Traces of antibodies remained in the patient's blood, but only in extremely low quantities. Her white blood cell count was normal, and the doctors determined that no further treatment was required.

What makes the case unique: Sparganosis infections typically appear in tissues located just under the skin, near the surface of the body. They rarely migrate to the internal organs. This is the first case to be documented in Shanghai of sparganosis in the lungs, the case report authors wrote.

Eating raw animal flesh is a long-standing cultural tradition in parts of Asia, and sometimes, small animals may be consumed while they are still alive. Living frogs are occasionally eaten as a folklore remedy for a variety of ailments; an 82-year-old woman in Hangzhou was hospitalized with a parasitic infection after she swallowed eight small, live frogs in an attempt to relieve her chronic back pain.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 60-year-old man in Warsaw, Poland

The symptoms: The man went to a hospital after experiencing vomiting for two days. Additionally, over the year prior, he had developed weakness and lost 40 pounds (18 kilograms) without trying to do so.

What happened next: Blood tests revealed that the man had elevated creatine and urea levels, indicating his kidneys were failing. His blood calcium levels were also dangerously high. CT scans then showed calcium deposits in his kidneys, pancreas and stomach, as well as scar-like areas in the back and lower parts of his lungs. These scans also showed unusual changes in his chest muscles; they appeared densely calcified.

Doctors treated the patient with a diuretic to help remove excess calcium, as well as intravenous fluids, a steroid, and a calcium-lowering drug. His calcium levels briefly dropped, and he was discharged with a couple prescriptions. However, three weeks later during a follow-up, doctors found his blood-calcium levels had risen again, and he was admitted to a nephrology ward.

The man was generally stable, but a physical exam showed noticeable changes in his upper-arm and chest muscles, matching the irregularities seen on the scans. The doctors then revisited the patient's medical history, and he shared a crucial detail: starting about 30 years earlier, he had started receiving "unknown intramuscular injections (probably containing testosterone)" into his chest and upper-arm muscles to enlarge them, according to a report of his case.

"He stressed that the last dose of these injections was received 2 years ago," the report authors noted. The exact frequency at which he'd historically gotten the injections is unclear.

Blood tests showed that the man's calcium-controlling parathyroid hormone was markedly low, ruling out a common hormonal cause of high calcium. The man also had no signs of hidden cancers in his digestive tract, no abnormalities on a urology evaluation, and no signs of an autoimmune condition. With other causes excluded, the medical team biopsied one of the abnormal muscle regions.

The diagnosis: Under the microscope, the muscle was filled with a silicone-like, oil-based substance and surrounded by dense calcium deposits. The team deduced that the man's past muscular injections probably contained synthol, a substance made primarily of oil that visually "plumps" up muscles, essentially inflating them like water balloons.

In this case, the synthol had triggered a persistent foreign-body reaction — the body essentially responding to material it could not break down. Over time, this reaction produced scarring and calcification, storing large amounts of calcium inside the muscle. And eventually, that calcium made its way into his bloodstream.

The treatment: A couple earlier reports of similar cases suggested that surgically removing the calcified muscle would be the only reliable long-term treatment for the man's persistently high calcium. In one previous patient, calcium levels returned to normal three months after the tissue was removed. However, in the man's case, the authors did not state whether the patient ultimately underwent surgery, nor did they describe his long-term outcome.

What makes the case unique: Synthol injections typically contain 85% medium-chain triglycerides, 7.5% of a local anesthetic like lidocaine, and 7.5% alcohol, purportedly for sterility. The oils act as the muscle-bulking agent, as the body does not easily process them, and the effects of these injections can linger for years. Even though it comes with serious risks, such as muscle deformity, chronic wounds and scarring, synthol is relatively easy to buy.

Only two other cases of high blood calcium linked to synthol injections had been reported, the case report authors noted, and both were from Lebanon. The underlying mechanism driving the effect remains unclear. Synthol's better-known complications usually appear soon after an injection, but in this patient, the effects apparently emerged years later, which made the cause unusually difficult to identify.

According to the authors, this case adds further evidence that "synthol intramuscular injections are among the causes of elevated serum calcium levels," despite its rarity.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 35-year-old woman in Brazil

The symptoms: The woman was referred to a hospital following a miscarriage at seven weeks of pregnancy. Leading up to the hospital visit, the woman's gynecologist had decided to check the patient's chromosomes to see if there was an underlying genetic reason for the pregnancy loss.

The most common karyotype, or chromosomal profile, for a woman is 46,XX. The 46 indicates 23 pairs of chromosomes in each cell. Two of these are sex chromosomes, which are usually XX for women and XY for men. However, the tests revealed that the patient's karyotype for her blood cells was 46,XY — the typical karyotype for a male.

What happened next: At the hospital, doctors performed two additional blood tests and ordered more tests to examine other chromosomes in the woman's body. Her skin cell karyotype was 46,XX.

The doctors then conducted a physical examination of the patient. Her visible traits were female, and they found no abnormalities in her genitals or reproductive system. Her hormone production was also within the normal range. As an adolescent, her sexual development had been normal, she told the doctors, with regular menstruation that began when she was 13 years old. There were no unusual health incidents in her medical history, and she was the first person in her family to be tested for a potential genetic disorder, the physicians wrote in a report describing her case.

The diagnosis: Doctors identified her condition as chimerism, in which the body contains at least two different sets of DNA across different cells.

This can sometimes happen after a blood transfusion or organ transplant, in which one person receives tissues (and thus DNA) from another individual. But chimerism can also happen naturally, when several fertilized eggs fuse in the uterus to produce a single fetus, or when cells and their DNA are "traded" in the womb. This swap can occur between a mother and an embryo, and sometimes between twins that share the same placenta or whose individual placentas interact in some way.

The patient in this case had a twin brother. When the doctors analyzed samples from the woman's brother and parents, they found genetic variants in the twin brother's XY blood cells that matched those in the patient's blood. They concluded that during fetal development, the woman had incorporated her twin's DNA into her blood cells while still retaining a different copy of DNA with XX chromosomes in the rest of her body's tissues.

"There was a transfusion process that we call feto-fetal transfusion," Dr. Gustavo Arantes Rosa Maciel, a co-author of the report and a professor in the Faculty of Medicine at the University of São Paulo, told BBC News Africa (translated from French). "At some point, the veins and arteries of the two children became intertwined in the umbilical cord."

The outcome: About 11 months after the patient's miscarriage and after she had completed testing at the hospital, the woman became pregnant again. As a precaution due to her prior miscarriage, the doctors prescribed supplements of the hormone progesterone to be given vaginally during the pregnancy. There were no complications, and she gave birth to a healthy boy.

What makes the case unique: In most cases of people with chimerism involving sex chromosomes, their condition carries substantial physical or reproductive issues. This is the first known example of complete blood chimerism in a woman who otherwise had typical female traits, had no health issues and was able to get pregnant. The case suggests that chimerism in humans is not necessarily a barrier to reproduction.

This is also the first case in the medical literature of a patient becoming a chimera in the womb via her twin's blood, according to the report.

And notably, even the karyotyping test for identifying the woman's condition is not commonly performed. It is not part of a standard medical visit. Therefore, it is unknown how common it is for individuals to carry hidden chromosomal anomalies, and incidences of blood chimerism are likely underreported as a result, the authors wrote. Indeed, studies have suggested that other types of chromosomal variations, such as having extra sex chromosomes, are also underreported.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 64-year-old woman in Canada

The symptoms: Paramedics brought the patient to the emergency department after she developed sudden weakness, nausea, vomiting, diarrhea and lower abdominal pain.

What happened next: The woman told doctors she'd developed the symptoms minutes after consuming two cups of homemade juice made from pureed calabash (Lagenaria siceraria), also known as bottle gourd. She said she'd made and drunk juice from store-bought calabash every day for years, according to a report of the case. However, on this occasion, she noted that it tasted "abnormally bitter," rather than having its more typical mild squash flavor.

Tests revealed that the woman's heart rate and breathing rate were high, and her blood pressure was initially high and then fell concerningly low. Her extremities were also unusually cool to the touch, indicating she had poor circulation. Meanwhile, one of the chambers of her heart was pumping very forcefully, and an echocardiogram suggested she was having other heart issues.

The medical team restored the woman's blood pressure to normal levels by giving her intravenous fluids, but she still subsequently had several episodes of "profound" low pressure. She also continued to experience diarrhea and vomited blood several times.

She was then transferred to the intensive care unit (ICU), where doctors examined her gastrointestinal tract via gastroscopy, in which a thin tube with a camera in it is inserted into the mouth and guided into the throat and stomach. They found that her stomach lining was inflamed and bleeding as a result of tissue damage, which was likely caused by poor oxygen delivery to the tissue.

The diagnosis: The patient was diagnosed with shock, a life-threatening condition in which blood flow starkly declines and ultimately injures organs. In this case, the shock stemmed from toxins in the squash juice. This "bitter bottle gourd poisoning" is a type of "toxic squash syndrome," which is caused by eating toxic substances sometimes found in squashes and gourds.

Calabash is specifically a "cucurbit," meaning it belongs to the Cucurbitaceae family that includes cucumbers, pumpkins, watermelon and zucchini. Cucurbits produce bitter-tasting chemicals called cucurbitacins, which can have toxic effects if consumed in large enough quantities. Domesticated varieties of these plants have been bred to contain minimal quantities of cucurbitacins so that they're both palatable and safe for humans to eat. But in some cases, cucurbits may accumulate these chemicals as they ripen, posing a rare risk to people who consume them.

"If ingested, cucurbitacin is toxic to humans by various purported albeit uncertain mechanisms," the report authors noted. The toxin is thought to disrupt signaling in cells and make blood vessels more permeable, and it ultimately injures mucous membranes in the body, especially in the digestive tract.

"It is suspected that the gourd’s degree of bitterness correlates with its cucurbitacin concentration and thus toxicity; however, this is not definitively supported in the literature," the authors added.

The treatment: There is no specific antidote to bitter-gourd poisoning, so the medical team continued to monitor the patient's vital signs and stabilize them as needed. Her shock and associated symptoms went away after she'd spent five days in the ICU.

The patient was then discharged, and on a follow-up call, she reported sudden and progressive hair loss that set in about two weeks after she'd been admitted to the hospital. The doctors noted that this is another likely symptom of "bitter bottle gourd poisoning and further supported this diagnosis." Hair loss has been reported in other cases of the syndrome.

What makes the case unique: Toxic squash syndrome is considered very rare, and this was the first such case ever reported in Canada. Similar cases had previously been reported in other countries, such as India, where calabash juice is used in some forms of traditional medicine.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 35-year-old woman in the Philippines

The symptoms: The woman visited the hospital because she had swelling in both armpits. The lumps were irregularly shaped and skin-colored, and measured 2.2 by 1.7 inches (5.5 by 4.2 centimeters) in the right armpit and 1.5 by 0.4 inches (3.9 by 0.9 cm) in the left armpit. The lumps were not tender or bleeding, nor were they unusually warm to the touch.

The patient was breastfeeding when the swellings appeared, as she'd recently had a baby. When doctors kneaded the swollen areas in her armpits, droplets of milk leaked from the hair follicles.

What happened next: According to the woman, similar swollen areas had first appeared 15 years earlier, following the birth of her first child. The swellings subsided after she stopped breastfeeding, she said, but they reappeared after subsequent births. Each time, the lumps in her armpits went away after she weaned the infants, her physicians wrote in a report of the case.

The diagnosis: After examining the underarm masses — noting their positions, shapes and other characteristics — the doctors conducted a biopsy. A tissue analysis confirmed that the lumps were polymastia, also known as ectopic or accessory breasts. (The term "ectopic" refers to tissues that appear in places other than where they're typically found.)

Ectopic breasts originate from a thickened line of tissue called the mammary ridge, which forms in the womb. Also called the milk line, this ridge is where rudimentary precursors of mammary glands develop. The ridge runs vertically on the fetal body wall from the armpit to the inner thigh. Sometimes, remnants of this tissue that were not reabsorbed during fetal development can become accessory breasts, which typically appear during puberty.

Ectopic breast tissue may grow in men or women at any location along the milk line, including the perineum (around the genitalia), groin, thigh or vulva. However, it is most commonly found in the underarm. On rare occasions, it takes shape on the face or back. Accessory breasts sometimes develop enough to include an areola and a nipple.

The treatment: In the woman's case, doctors suggested surgical removal of the mammary tissue in her armpits. However, because her prior experience suggested that the engorged tissue would shrink once she stopped breastfeeding, she decided not to have the surgery.

The doctors then recommended that she continue to monitor her underarm regions for any further swellings and that she have these areas checked during her regular screenings for breast cancer.

What makes the case unique: It's fairly rare for breast tissue to grow in parts of the body where it isn't supposed to. According to the case report, the condition affects about 2% to 6% of women and 1% to 3% of men. The condition can run in families and is estimated to be inherited in about 6% of cases. But according to the woman in this case, no member of her family had a history of similar swellings.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 12-month-old boy in Portugal

The symptoms: Shortly after eating different types of fish, the child would develop an odor of rotting fish emanating from his body. The smell was noxious and powerful, especially around his head and hands. He was 10 months old the first time this happened. (The child had been exclusively breastfed as an infant and began eating solid foods at 7 months of age.) His mother temporarily put him on a fish-free diet, but after she reintroduced fish to his meals two months later, the odor returned.

What happened next: When doctors examined the child, they did not detect a fishy smell, though they noted that he had not eaten fish before his medical visit, according to a report of the case. They detected no abnormalities in the boy's neurodevelopment or growth, and laboratory tests showed that his kidneys, liver and thyroid were functioning normally.

The diagnosis: Doctors suspected that the child had developed a rare metabolic disorder called trimethylaminuria, also known as "fish odor syndrome," in which breath, saliva, sweat and urine smell like decaying fish. Rotten fish gets its distinctive smell from a molecule called trimethylamine, and the human body produces trimethylamine from nitrogen-rich foods, such as fish. An enzyme called flavin-containing monooxygenase 3 (FMO3) breaks down trimethylamine in the body, changing it to the odorless compound trimethylamine N-oxide. But if the enzyme isn't working as it should, trimethylamine accumulates in the body and can make a person produce a foul, rotting-fish aroma.

A metabolic pediatrician conducted a molecular analysis of the child's FMO3 gene, which makes the FMO3 enzyme, and found a combination of genetic variants that could disrupt the production of the enzyme, leading to a mild or temporary type of trimethylaminuria.

The treatment: The doctors recommended that the child's parents reintroduce fish to the child's diet in small increments and that they manage any lingering smell with a low-pH soap, which reduces body odors. Over time, the rotten smell after fish meals weakened. By the time the child was 19 months old, he was eating fish five or six times per week without experiencing any malodorous symptoms afterward, and the symptoms had not returned by the time he was 3 years old.

What makes the case unique: There is no treatment or cure for trimethylaminuria; its primary cause is genetic, and in adults the condition is frequently chronic. In this case, the child's temporary bout of trimethylaminuria was likely shaped by a combination of factors, including inherited variants of the FMO3 gene and the immaturity of his metabolism, his physicians wrote in the report.

As the boy's metabolic system matured, the FMO3 enzyme improved its ability to break down trimethylamine. This child's case and others suggest that the causes of trimethylaminuria are more nuanced than once thought and that the disorder varies in severity, according to the report.

Trimethylaminuria is an uncommon disorder, with just a few hundred cases described in medical literature. However, the condition may be underdiagnosed, as people with trimethylaminuria often link their symptoms to personal hygiene habits and do not seek medical treatment for the unusual smell.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 3-year-old boy in San Antonio, Texas

What happened: The patient's mother worked as a microbiology lab technician, and part of her job involved visiting physicians' offices to gather lab dishes of clinical samples that had been collected from patients. One day, she had her son in the car while she was making these rounds, according to a report of the case, which was published in 1984.

While en route, she stopped at a grocery store and then drove home to drop off her purchases. Once home, she briefly left her son in the parked car as she brought the groceries inside. When she returned, she found that her son had crawled into the backseat where she'd placed the clinical cultures — and that he'd eaten most of the contents of one lab dish.

That dish contained "chocolate agar," a brownish medium used to grow bacteria that's made of split-open red blood cells. It's named for its color and contains no actual chocolate but nonetheless may have looked appetizing to the child, the report noted.

The diagnosis: The mother immediately brought her child to their family doctor, who found that the remaining material from the lab dish contained Neisseria gonorrhoeae, the bacteria that causes gonorrhea. Doctors decided to monitor the boy for signs of bacterial infection in his throat. Up to six days after he ate the agar, the boy's throat swabs tested negative for N. gonorrhoeae. No test was taken on the seventh day, but on the eighth day, he tested positive.

(The report didn't note whether the boy experienced any symptoms of the infection, and often, gonorrhea infections of the mouth and throat cause no symptoms. Possible symptoms include swollen lymph nodes and throat redness and soreness. Untreated gonorrhea can sometimes lead to dangerous complications, such as bloodstream infections or harmful immune system changes.)

The treatment: The doctors treated the infection following the Centers for Disease Control and Prevention's (CDC) guidelines at the time. This involved giving the patient intermuscular injections of an antibiotic called procaine penicillin G. (Nowadays, penicillin G is not recommended as a therapy for gonorrhea, in part because many strains of N. gonorrhoea circulating in the U.S. are now resistant to the drug's effects.)

The boy was also given probenecid mixed into ice cream. Probenecid helps boost the effect of some antibiotics by slowing the rate at which they're cleared from the body. This course of treatment "produced a prompt cure" and the boy tested negative for the bacteria on tests given afterward, the report said.

What makes the case unique: Gonorrhea most often spreads via sexual contact, through exposure to semen or vaginal fluid carrying the bacteria. As such, evidence of the infection in children can often point to sexual abuse taking place. In this case, however, doctors observed a very unusual instance of non-sexually transmitted gonorrhea related to exposure to laboratory cultures.

Cases of gonorrhea had been tied to laboratory exposures before — for example, a lab technician was once infected in the eye with N. gonorrhoeae while running experiments with the bacteria. When it comes to pediatric cases, though, this route of transmission is odd because children are not typically in environments where they could be inadvertently exposed to N. gonorrhoeae cultures.

Besides underscoring the importance of safety protocols in research, this case "reminds us of the risks involved in leaving children unattended in automobiles," the report authors added.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 31-year-old woman

The symptoms: The woman visited a clinic because she had long experienced bursts of uncontrollable laughter, which doctors described as "mirthless" in a report of her case. According to the patient, she had been having these intermittent bursts of involuntary laughter since infancy, but her condition had never been formally investigated or diagnosed.

She said that before each episode started, she would experience a "feeling of dread" in her neck and chest. During the involuntary laughing incidents, she could not speak or swallow, and she had difficulty breathing. Each outburst lasted a few seconds and typically occurred about once per day, usually shortly after the woman awoke in the morning.

The woman noted that, when she was a child, each episode would last several minutes and occurred more frequently — about six or seven times a day, and sometimes while she was asleep. Her parents did not recognize the laughter as being beyond her control. Rather, they thought her laughing was deliberate and would ask her to stop, the patient reported. As she grew older, the bouts of laughter became shorter and happened less frequently.

What happened next: Prior to the patient's visit to the clinic, MRI and electroencephalography (EEG) of her brain showed no abnormalities. However, when the clinicians examined videos of her laughing episodes, they noted that they closely resembled gelastic seizures. This type of seizure commonly triggers uncontrolled laughing, giggling or smirking, but it can also cause grunting, mumbling or lip smacking. It is named after the Greek word for laughter ("gelastikos").

Gelastic seizures are typically focal, meaning they're caused by abnormal electrical activity in one specific part of the brain. On a second MRI, doctors discovered an area of abnormality in the hypothalamus, a key structure for maintaining homeostasis. The abnormality measured about 0.2 inches (5 millimeters) wide.

The diagnosis: They identified the lesion as a hypothalamic hamartoma, a noncancerous lesion that occurs during fetal development. Gelastic seizures that provoke bursts of involuntary laughter, during which the individual is aware of their actions but can't control them, are a hallmark of this lesion. The exact reason these lesions trigger giggling fits isn't fully understood.

The treatment: The patient had previously taken trial doses of the anti-seizure drugs levetiracetam and lamotrigine, which are used to treat epilepsy, with no effect. Because her episodes were not severe, the woman decided that she did not want medication.

She was not experiencing any other behavioral or cognitive issues and the attacks had declined in severity and frequency over time, so the doctors at the clinic determined that no additional treatment was required.

What makes the case unique: Hypothalamic hamartomas are rare, but when they do occur, they are typically accompanied by cognitive and behavioral impairment. In children, the growths can cause developmental delays or trigger the early onset of puberty, because the hypothalamus helps regulate hormones. Patients that have gelastic seizures triggered by these lesions often develop more severe forms of epilepsy and experience other types of seizures down the line.

The woman's case is highly unusual because her symptoms naturally declined to a manageable level. This benign outcome of epilepsy associated with hypothalamic hamartomas, "to our knowledge, has not been previously reported," the doctors wrote.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 37-year-old woman in Philadelphia

The symptoms: The patient went to the emergency department after four days of pain, swelling and bruising on the upper part of her left knee. She reported that these symptoms appeared after she'd used a massage gun on her leg.

What happened next: Doctors took the woman's medical history, noting that she had been on blood thinners for about six years due to previously having a blood clot in her lung and a stroke caused by a small birth defect in her heart that had allowed a clot to reach her brain. She also reported heavy menstrual bleeding.

Doctors saw bruising on her thigh, knee and calf, with swelling but no joint damage or blood clots on scans. They advised the patient to stop using the massage gun, continue her medication regimen and follow up later.

A few weeks later, she returned with shortness of breath and lightheadedness, and she still had bruising on her leg. An MRI of the leg showed tissue swelling and a small muscle bruise, typically caused by blunt trauma to the tissue. Blood work revealed that her red blood cells and hemoglobin — the part of blood that carries oxygen — had dropped to dangerously low levels.

Suspecting that the patient may have anemia due to an iron deficiency, the medical team also checked her iron levels and found they were low. To search for a potential source of blood loss, doctors ran stool tests and did stomach and colon scopes, all of which were normal.

The patient was discharged with a prescription for daily iron tablets and weekly intravenous iron, but these failed to keep her hemoglobin levels up. She then received several blood transfusions, with each transfusion briefly lifting her numbers, only for them to fall again within a week. Concerns about her low hemoglobin levels prompted doctors to pause her blood thinners and to have an intrauterine device placed, to stop any menstrual bleeding.

About six weeks into this decline, she returned to the emergency department with chest pain, night sweats, weight loss and worsening breathlessness. Her lungs sounded clear, but scans showed the right side of her heart was enlarged and weak, and pressures in her lungs were very high, a condition called pulmonary hypertension. Her oxygen levels worsened overnight, so the doctors transferred her to intensive care. At that point, doctors noticed that she had tiny red spots around the hair follicles on her legs and that the hairs twisted into corkscrews; she also had swollen, purplish gums.

The diagnosis: The red spots, corkscrew hairs and swollen gums were classic signs of vitamin C deficiency, and tests confirmed her vitamin C level was undetectable. Upon further questioning, she then reported that citrus foods gave her hives, so she had avoided them for years. (Additional fruits and vegetables can also be good sources of vitamin C; the woman's doctors didn't note whether she consumed any of those other foods.)

Without vitamin C, the body cannot build strong collagen, the scaffolding that supports blood vessels and tissues. Fragile vessels leak, bruises linger, wounds heal poorly, and in rare cases, the strain can affect the function of the heart and lungs.

The treatment: Doctors started the patient on high-dose oral vitamin C supplements and the turnaround was dramatic. Within 48 hours, she was stable enough to leave intensive care. She was then discharged with a prescription for vitamin C supplements, an iron-containing multivitamin, and medications for her pulmonary hypertension.

Over the next weeks, her blood counts rose without more transfusions, her bruises and gum swelling faded, and her breathing improved. Her blood thinner was restarted safely. Within six months of discharge, she no longer needed medicines for pulmonary hypertension, her heart function and scans returned to normal, and she was back to exercising as she had before the bruising event.

What makes the case unique: Scurvy is usually remembered as a historical sailor's disease, but this form of malnutrition can still affect people in the modern day.

Most cases of scurvy cause fatigue, easy bruising or mild anemia, but this patient developed transfusion-dependent anemia, meaning she required regular blood transfusions to keep her blood counts up. Her condition was so severe it did not respond to iron therapy — a rare occurrence described only occasionally in medical literature.

She also developed high lung pressure with strain in the right side of the heart, an uncommon complication of scurvy that typically improves only when vitamin C is replaced, not with standard drugs for the treatment of pulmonary hypertension.

"The current case serves as a reminder that scurvy continues to occur in the United States and highlights its potential severity and clinical features," doctors wrote in a report of the case. "It also underscores the importance of a dietary-history review, especially when a diagnosis is elusive."

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 34-year-old man named Brent Chapman in British Columbia, Canada

The medical history: When Chapman was 13 years old, he had a rare and serious autoimmune reaction after taking a normal dose of ibuprofen. This reaction, known as Stevens-Johnson syndrome, trips the immune system, causing cells to attack the skin and mucus membranes. In this case, the syndrome caused severe burn-like injuries all over Chapman's body, including the surfaces of his eyes.

His left cornea — the transparent dome that covers the eye — was destroyed when one of these injuries became infected, and he lost most of the vision in his right eye due to corneal damage.

Over the next two decades, Chapman had more than 50 surgeries — including 10 attempts at corneal implants in his right eye — but most were unsuccessful. Some of the surgeries temporarily restored partial vision, but none could permanently restore his sight.

What happened next: Doctors proposed a surgical procedure called osteo-odonto-keratoprosthesis, or tooth-in-eye surgery, to restore vision in Chapman's right eye. The technique has been around since the 1960s but had never before been performed in Canada before Chapman's case.

The procedure involves removing one of the patient's teeth and then implanting it in their eye socket, where it serves as a platform for a transparent, plastic lens. The lens stands in for the injured cornea and enables light to enter the eye.

Candidates for tooth-in-eye surgery typically have damaged corneas and a healthy retina and optic nerve — meaning the light-sensitive tissues and nerves at the back of the eye still work well. According to a 2022 study of 59 patients who underwent tooth-in-eye surgery, 94% showed long-term vision retention, based on follow-up visits spanning 30 years.

The treatment: Dr. Greg Moloney, a clinical associate professor of ophthalmology at the University of British Columbia, performed the first stage of the operation on Chapman and two other Canadian patients in February 2025.

Moloney first removed one of Chapman's canine teeth, as well as a thin layer of the bone that had been surrounding it. This kept the tooth supplied with blood and oxygen. The tooth was then shaved flat, into a small block, before being drilled and fitted with a lens-holding plastic cylinder. The sculpted tooth was then implanted in Chapman's cheek to enable soft tissue to grow around it for several months.

Then, in June, the tooth was removed and surgically implanted in Chapman's right eye. Because the tooth and surrounding soft tissue come from the patient, their body is less likely to reject a tooth-in-eye implant.

Almost immediately after the surgery, Chapman could perceive movement. His vision gradually sharpened over the next month, though there was some visual distortion, and he had another surgery in August to correct the lens placement. Later that month, tests with corrective glasses showed that he had 20/30 vision; objects that are visible at 30 feet (9 meters) for a person with perfect vision were in focus for Chapman at 20 feet (6 meters).

What makes the case unique: Tooth-in-eye surgery is considered a last resort for blindness caused by corneal damage. The multipart operation takes more than 12 hours, not counting the time that tissue grows around the tooth in the cheek, and there are few specialists who perform it worldwide.

Doctors have previously performed tooth-in-eye surgery in Australia, Chile, Egypt, Germany, India, Italy, Japan, Spain, the United Kingdom and the United States. To date, only several hundred people have received the procedure.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 44-year-old man in Tanzania

The symptoms: For 10 days, pus oozed from an opening in the man's chest below his right nipple, prompting him to visit the emergency room. He told doctors he had no pain or difficulty breathing. He did not have a fever, and his vital signs were normal.

What happened next: When the doctors examined the man, they found that his rib cage on the right side of his chest was flattened at the front and that his chest did not fully expand on that side when he inhaled. They confirmed that "foul-smelling" pus was leaking from a cavity under the nipple, they wrote in a report of the case.

During the examination, the man reported that, eight years earlier, he had been stabbed repeatedly in the chest, back, abdomen and face during a "violent altercation." No imaging tests were performed at that time, and he received only superficial first-aid treatment for the multiple knife wounds. For eight years, he had no health issues resulting from those injuries, he said.

The diagnosis: An X-ray revealed a large metallic knife blade lodged inside the man's thoracic cavity. Also known as the chest cavity, this hollow chamber is located above the abdomen and contains the heart and lungs. The blade, which extended from the rear of the rib cage to the front, had entered the man's back near his right scapula, or shoulder blade.

The knife's blade slid between the fifth and sixth ribs in the patient's back and then stuck there, with the knife's tip positioned between the third and fourth ribs at the front of his rib cage. A CT scan showed healed fractures in his scapula and in several ribs. Layers of pus and dead or dying tissue surrounded the knife blade.

One way the body protects itself against foreign objects is through a process called fibrous capsule formation, in which the immune system cocoons the object in collagen and other fibers to limit damage and inflammation in the surrounding tissue. Such encapsulation of the knife is likely what enabled the man to spend the next eight years unaware that there was a blade inside his chest, according to the report.

The treatment: Surgeons at the hospital performed a thoracotomy, in which they cut into the man's chest wall to remove the blade. They drained the accumulated pus, flushed the chest cavity with a solution of sodium chloride, installed a drainage tube and finally sutured the wound. The patient received broad-spectrum antibiotics for seven days and was closely monitored for signs of infection following the surgery.

Doctors removed the drainage tube after the eighth day, and the man was discharged two days later. He returned to the hospital for two follow-up appointments: one two weeks after his surgery, and one six weeks afterward. At both visits, he was infection-free and experienced no further complications.

What makes the case unique: After a traumatic chest injury, it's not unusual for part or all of the penetrating object to be left behind in the chest cavity. However, most of the time, these foreign bodies are small ballistic projectiles, such as bullets, which are often difficult to locate and remove.

By comparison, large shards — for example, entire knife blades or other stabbing weapons — that break off and become lodged in the chest are less commonly documented in the medical literature. And in most cases, these objects do not go undetected for years; they are typically identified and removed within weeks or months, according to the report.

This article is for informational purposes only and is not meant to offer medical advice.