Gestational Choriocarcinoma

**Semantic type:** Neoplastic Process

**Definition:** A rare, highly malignant epithelial tumor that develops from a hydatidiform mole (50%), following abortion (25%), or during normal pregnancy (22%). It is characterized by the presence of invasive and anaplastic trophoblastic tissue composed of intermediate trophoblastic cells, cytotrophoblasts and syncytiotrophoblasts, abundant vascularity, and secretion of human chorionic gonadotropin. Because of rapid growth and a high propensity for hemorrhage, this neoplasm often constitutes a medical emergency.