Not for Women Only: 2 Rare Cases of Men Diagnosed With Endometriosis

Not for Women Only: 2 Rare Cases of Men Diagnosed With Endometriosis

Two rare cases of endometriosis affecting male patients have been reported by researchers at Indiana University, who state that the disease should be considered when attempting to diagnosis men who have genitourinary tract cysts.

The cases were described in the study “Endometriosis With Cystic Degeneration: A Rare Disease of Males,” published in the journal International Journal of Surgical Pathology.

Endometriosis is perceived as a woman’s disease, affecting about 10 percent of women of reproductive age worldwide. It is characterized by the overgrowth of endometrial tissue outside the uterus, causing severe pain and infertility.

But this disease also can affect men, although such cases are very rare. Indeed, only 17 cases have been documented in medical literature.

The first patient presented in this report was a man, age 50, who developed a mass in his right testicle.

The affected testicle was removed surgically and the tissue was analyzed, revealing that the mass was a cyst containing a brown fluid and debris of dead tissue. A more detailed analysis showed that the cyst tissue had elongated structures and lined glands that resembled the endometrium, while the surrounding testicular tissue was all normal.

The cyst tissue sample showed signs of inflammation and infiltration of immune cells, but with no cancer-related markers. In addition, researchers found it was positive for CD10 protein, which is a sensitive diagnostic marker of endometrium tissue, although it was negative for the female sex hormone receptor (estrogen receptor).

Supported by the CD10 presence, he received the diagnosis of endometriosis with cystic degeneration.

The second case was of a 43-year-old overweight man with an enlarged mass affecting the testis’  surrounding structures. The size of the mass was tracked closely for about five years before it started to increase up to 2.7 times the initial detectable size.

The mass was removed with a small incision, showing a tan-pink partially hemorrhagic (bloody) lining and smooth external surface. Similar to the aforementioned case, the cyst tissue was found to be composed by structures and cells that resembled the endometrium, and had infiltration of immune cells.

Further analysis confirmed that the cyst was positive for both estrogen and progesterone receptors (the two main female sex hormones), as well as for the CD10 marker. Based on these findings, he also received the final diagnosis of endometriosis with cystic degeneration.

“The diagnosis of endometriosis is usually straightforward in women; however, the rarity of the disease in men makes the diagnosis challenging especially when it presents as a testicular mass,” the researchers stated.

The origin of endometriosis in men is still unknown. One hypothesis is that it could be triggered by hormonal treatments that would promote the growth of endometrium tissue remnants of the embryonic phase. But in the two cases presented, none of the patients had a history of hormonal therapy or of another medical condition that could promote female hormone production.

“Although endometriosis is an extremely rare lesion in men, it should be considered in the differential diagnosis of patients presenting with banal-appearing cystic lesion, especially within or adjacent to the genitourinary tract system,” the team wrote.

“Such alertness will guide the appropriate clinical management and avoid unnecessary surgical intervention,” they added.