Epithelioid trophoblastic tumor: A single institution case series at the New England Trophoblastic Disease Center.

Objective: Epithelioid trophoblastic tumor (ETT) is a rare form of gestational trophoblastic neoplasm which is distinct based on its development from intermediate trophoblast cells and nodular growth pattern. The aim of this study is to describe a case series from a single institution with a review of the literature to better understand the clinical characteristics and outcomes for patients with ETT.

Methods: A retrospective review was performed using the IRB approved New England Trophoblastic Disease Center (NETDC) database from 1998 to 2014. Eight patients were identified of which seven had complete records. Follow-up data was obtained from the longitudinal medical records.

Results: Four (57.1%) patients presented with vaginal bleeding and two (28.6%) patients were asymptomatic at presentation. Three (42.9%) patients had extrauterine disease. All three patients with extrauterine disease who received chemotherapy had stable or progressive disease at follow-up. Only two (29%) patients who presented with non-metastatic disease and underwent hysterectomy were alive with no evidence of disease. The mean interval following antecedent pregnancy was 104months. All patients with an interval >4years demonstrated stable or progressive disease despite intensive chemotherapy. Two patients with non-metastatic disease who declined hysterectomy developed stable or progressive disease despite chemotherapy.

Conclusions: This series highlights several features of ETT including the potential for asymptomatic presentation of extrauterine disease. The series also demonstrates chemoresistance, even with multi-agent therapy and a poor prognosis with extrauterine disease and an interval greater than 4years following the antecedent pregnancy suggesting that surgery remains critical in disease control.