Placental Site Trophoblastic Tumors and Epithelioid Trophoblastic Tumors

Placental site trophoblastic disease (PSTT) and epithelioid trophoblastic tumor (ETT) are the rarest forms of gestational trophoblastic neoplasia (GTN) with unique clinical features and treatment considerations. Unlike other GTN, human chorionic gonadotropin (hCG) is minimally, if at all, elevated. Additionally, unlike other GTN, WHO risk scores are not applied to PSTT/ETT. Management of PSTT/ETT is predominately surgical with hysterectomy and possible lymphadenectomy. There are case reports of fertility sparing surgery for uterine confined disease. Multi-agent chemotherapy ± pembrolizumab is added for those with high risk features defined as advanced stage disease and those diagnosed ≥48 months from the antecedent pregnancy. Survival for early stage, low risk disease remains quite good but the prognosis for high-risk disease is poor and an scenario for which novel treatments are needed.