[Placental-site trophoblastic tumor of the uterus--a case report].

A case of placental-site trophoblastic tumor arising in the uterus is reported. The patient, a 34-year-old female, complained of irregular menstruation. Under the diagnosis of a tumor in the uterus or the ovary, a simple total hysterectomy and right adnexectomy were performed. Histologically, the tumor cells, which were large, polygonal or rounded in shape, had infiltrated into the myometrium in clusters or singly. Immunohistochemically, most of the tumor cells were positive to hPL. Further, hCG also was present in some tumor cells, though only weakly. Because of these findings, this case was diagnosed as a placental-site trophoblastic tumor (PSTT).