Endometriosis With Cystic Degeneration: A Rare Disease of Males

Endometriosis in men is extremely rare with only a few cases reported in the English literature. Different theories have been proposed as to its origin. In this article, we describe the clinicopathologic features of 2 cases of endometriosis occurring in male patients. The patients’ ages were 50 and 43 years, and sizes were 2 and 5.2 cm, respectively. No significant chemical or hormonal exposure was identified. Both patients presented with a testicular mass. Grossly, both lesions were cystic and contained hemorrhagic fluid. Microscopic examination revealed cysts and occasional glands lined by low columnar to cuboidal epithelium, surrounded by spindle cell stroma with abundant hemosiderin-laden macrophages reminiscent of endometrium. One case was predominantly intratesticular, with a minute focus of endometrial-type glands and spindled stroma within the tunica vaginalis. Focal chronic inflammation and epithelial denudation were present in both cases. The surrounding testicular and epididymal structures adjacent to the cystic mass were unremarkable. In summary, endometriosis is an extremely rare lesion in men. The presence of these lesions in both cases along the route of the Müllerian duct supports the theory that these lesions arise from embryonic remnants. Awareness of this entity is crucial for general pathologists to avoid wrong diagnosis and unnecessary management.