子宮鏡下生検で診断されたEpithelioid trophoblastic tumor（ETT）の１例

抄録

　Epithelioid trophoblastic tumor (ETT) is classified as an intermediate trophoblastic tumor. Like placental site trophoblastic tumor, ETT is rare and is caused by tumorigenesis of intermediate trophoblastic cells. In this case report, we described a 32-year-old patient with ETT, diagnosed by hysteroscopic biopsy, and treated by total laparoscopic hysterectomy. The patient survived without recurrence after surgery. The patient had two pregnancies and two vaginal deliveries at the ages of 26 and 29 years. A transvaginal ultrasonography showed a hyperechoic area on the posterior wall of the uterus, and thus, endometrial biopsy was performed. Histopathologic examination suspected a placental remnant, but a definitive diagnosis was not reached, and the patient underwent hysteroscopy to obtain a definitive diagnosis. The hysteroscopic examination revealed white thickened tissues on the posterior wall of the uterus, which was biopsied. Histopathologic examination revealed a honeycomb-like proliferation of round, mononuclear atypical giant cells and hyaline degeneration of the interstitium. Immunohistochemical staining was positive for placental alkaline phosphatase (PLAP). Consequently, ETT was diagnosed. The CT showed no evidence of lymph node enlargement or distant metastasis. Management involved laparoscopic surgery, which confirmed the absence of disseminated lesions in the abdominal cavity, laparoscopic total hysterectomy, and bilateral salpingectomy. The patient has been followed up regularly, including monitoring of hCG and CT. Two years have passed without any postoperative recurrence. The hysteroscopic observation and precise excision of the lesion led to the diagnosis of ETT and provided important information for treatment planning.