Epithelioid Trophoblastic Tumor Predominant Mixed Germ Cell Tumor of the Testis: A Case Report and Review of the Literature.

An epithelioid trophoblastic tumor is a rare form of gestational trophoblastic neoplasia that mostly affects the uterus and endocervix in female patients of the reproductive age group. The tumor is believed to arise from chorion leave-type intermediate trophoblast. The epithelioid trophoblastic tumor in men is extremely rare and mostly described in association with mixed germ cell tumors of the testis. It is more commonly identified at the metastatic sites than in the testis. The epithelioid trophoblastic tumor should be differentiated from placental site trophoblastic tumor and squamous cell carcinoma. The distinctive morphology and characteristic immunohistochemical staining pattern help differentiate epithelioid trophoblastic tumors from other neoplasms. Only 7 male patients with epithelioid trophoblastic tumors have been described to date. Of these 7 patients, 4 were in metastatic sites, 2 in the testis, and 1 in the lung without the involvement of the testis or retroperitoneum. The proportion of epithelioid trophoblastic tumors was only 5% in the 2 patients with testis involvement. Here, we report the third patient with a primary testicular epithelioid trophoblastic tumor in a young man. Further, this is the first report to document epithelioid trophoblastic tumor as dominant histology in a testicular germ cell tumor.