Choriocarcinoma is a rare and aggressive type of cancer that primarily arises from the cells that would normally develop into the placenta during pregnancy. It is classified as a type of gestational trophoblastic disease and can occur after a normal pregnancy, miscarriage, or molar pregnancy. This cancer is characterized by the rapid growth of abnormal cells and can spread to other parts of the body, particularly the lungs and liver. Symptoms of choriocarcinoma may include abnormal bleeding, pelvic pain, and elevated levels of human chorionic gonadotropin (hCG) in the blood. Diagnosis typically involves blood tests, imaging studies, and sometimes a biopsy. Treatment often includes chemotherapy, which is effective in most cases, especially when detected early.