The main difference between erosive staphyloma and gravidarium is that erosive staphyloma is a malignant trophoblastic tumor while gravidarium is a benign condition. The main difference between the two is that the uterus returns to normal size within a short period of time after a gravidectomy. In most cases, the uterus does not return to normal size for 4-6 weeks after the evacuation of the fetus and vaginal bleeding starts a few months after the evacuation. In addition, erosive staphylococci will have metastatic lesions, the most common being lungs, followed by vaginal and parietal uterus, with brain metastases being less common. Benign staphylococci do not have metastatic lesions in the clinic, which is the difference between the two.