Both erosive staphyloma and choriocarcinoma belong to gestational trophoblastic disease and are both malignant diseases. The main differences between erosive staphyloma and choriocarcinoma include malignancy, secondary disease, and focal tissue, as follows: First, malignancy: erosive staphyloma is less malignant than choriocarcinoma and has a better prognosis, while choriocarcinoma is extremely malignant, metastases occur early and widely, and the mortality rate of choriocarcinoma reached over 90% before the introduction of chemotherapy drugs. Secondly, secondary diseases: all erosive staphyloma is secondary to staphyloma pregnancy, choriocarcinoma can be secondary to staphyloma pregnancy, but it can also be secondary to non-staphyloma pregnancy, that is, when miscarriage, term delivery, ectopic pregnancy is found to be gestational trophoblastic tumor, it is choriocarcinoma, not erosive staphyloma. Third, focal tissue: if you see villi or degenerated villi in the focal tissue, you can diagnose erosive staphyloma. If only patches of trophoblastic infiltration and necrotic hemorrhage are seen, and no villi structure is seen, then the diagnosis is choriocarcinoma.