Gestational trophoblastic neoplasia (GTN), a subset of gestational trophoblastic disease (GTD), occurs when tumors develop in the cells that would normally form the placenta during pregnancy. The NCCN Guidelines for Gestational Trophoblastic Neoplasia provides treatment recommendations for various types of GTD including hydatidiform mole, persistent post-molar GTN, low-risk GTN, high-risk GTN, and intermediate trophoblastic tumor.