Objective: This study aimed to investigate the clinicopathologic features and prognostic factor in patients with epithelioid trophoblastic tumor (ETT).

Methods: From January 2002 to June 2010, the clinicopathologic characteristics, treatments, outcomes, and prognosis of 9 patients with ETT were analyzed retrospectively in our institution.

Results: Of 9 patients, 8 (88.9%) had metastases. The histopathologic results of 7 patients (77.8%) with poor outcomes showed diffuse multifocal disease within the uterus, full-thickness myometrial invasion, uterine serosal involvement, and extensive necrosis. The size of the uterus exceeded 8 weeks of gestation in 7 patients. Two of them had poorly differentiated carcinoma. All patients were treated with multimodality treatment that combined with surgery and chemotherapy. After the initial treatments, 5 patients with International Federation of Gynecology and Obstetrics stage I achieved complete remission (CR), 1 patient achieved partial remission, and 3 patients (33.3%) had no response to treatments and died of progressive disease. After following up for 6 to 107 months (mean, 24 months), 4 (44.4%) of the 5 patients with initial CR had relapse: 3 of them achieved a second CR and the other 1 was under treatment.

Conclusions: Epithelioid trophoblastic tumor is a rare and special type of intermediate trophoblastic tumor with a high degree of malignancy and poor prognosis. Multifocal lesions in bulky uterus, combined with full-thickness myometrial invasion and uterine serosal involvement, could be related to poor outcomes in patients with ETT. The prognosis of ETT could be improved by increasing diagnostic accuracy, identifying prognostic factor at an early stage, and providing early intensive multimodality treatment to patients with poor prognostic factors.