Gestational trophoblastic disease (GTD) is a rare entity including hydatidiform moles (HMs), placental site trophoblastic tumors (PSTTs), epithelioid trophoblastic tumors (ETTs) and choriocarcinomas (CC). All these conditions arise from the placental villous trophoblast. PSTT, ETT and choriocarcinomas are also referred to as gestational trophoblastic neoplasia (GTN) because they can progress or invade and metastatize.
