Trophoblastic Neoplasia refers to a group of rare tumors that arise from trophoblastic tissue, which is involved in pregnancy. These tumors can develop after a normal pregnancy, miscarriage, or molar pregnancy, and they include conditions like gestational trophoblastic disease and choriocarcinoma. The most common type, gestational trophoblastic neoplasia, can produce high levels of the hormone human chorionic gonadotropin (hCG). Diagnosis typically involves blood tests and imaging studies, while treatment may include chemotherapy or surgery, depending on the tumor's type and stage.