Epithelioid trophoblastic tumor of the uterus: cytological and immunohistochemical observation of a case.

Epithelioid trophoblastic tumor (ETT) is a new entity of trophoblastic tumor and 14 such cases were reported by Shih and Kurman in 1998. However, only three subsequent cases supporting ETT have been reported. Recently, we experienced a case of ETT in a 37-year-old woman whose preoperative endometrial brushings showed atypical mononucleate giant cells and who underwent hysterectomy with the diagnosis of a uterine fibroid. The specimens revealed a 2.5 x 3.0 cm yellow-tan intramural nodule located in the lower uterine segment, which was composed of a neoplastic proliferation of intermediate trophoblasts in epithelioid arrangements. Immunohistochemically, the tumor cells were diffusely positive for cytokeratin and inhibin-alpha, and focally positive for human chorionic gonadotropin and human placental lactogen. She presented an uneventful clinical course as of September 2001.