Diagnostic dilemma: Man who donated his body after death had rare 'triple penis'

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.

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