Generally speaking, the diagnosis of malignant tumors requires pathological diagnosis, that is, we have to obtain a biopsy to determine the presence of cancer under the microscope. Because choriocarcinoma has a special feature, that is, it can secrete human chorionic gonadotropin, or HCG as we usually call it, the rise of HCG can help us to determine the presence of choriocarcinoma. If a patient has a history of gravidity or pregnancy and HCG is abnormal, trophoblastic tumor can be considered in most cases when placental residue or ectopic pregnancy is excluded. Within the trophoblastic tumor, if we can exclude staphyloma or invasive staphyloma, the diagnosis of choriocarcinoma can be established at this time.