The main difference between choriocarcinoma and erosive staphyloma is the ability to visualize chorionic structures on biopsy. Erosive staphylococcus, in which chorionic villous structures can be seen in the pathologic tissue, is a junctional tumor between staphylococcus and chorionic epithelial carcinoma. Erosive staphylococcal blister-like chorionic villi invade the myometrium, causing necrotic hemorrhage in the myometrium, and even invade outside the uterus to involve the broad ligament, or embolize via blood vessels to distant organs such as the vagina, lungs, and brain. Most erosive gravidarians are sensitive to chemotherapy and have a good prognosis. Choriocarcinoma, or choriocarcinoma, in which choriocarpal structures are not visible on biopsy microscopy, is a highly aggressive malignant tumor originating from the trophoblastic epithelium of the chorionic villi of pregnancy, and in a minority of cases, may occur in the gonadal glands or multipotential cells of other tissues. The vast majority are associated with pregnancy, with approximately 50% secondary to gravida, 25% secondary to spontaneous abortion, 20% occurring after normal delivery, and 5% occurring in preterm and ectopic pregnancies, among others. Women under 20 and over 40 years of age are at high risk, and the strong correlation between onset and age suggests that the tumor is more likely to arise from an abnormally fertilized egg rather than from the chorionic epithelium.