Clear cell carcinoma and endometrioid carcinoma arising in a endometriotic cyst of the ovary.

A case of two tumors arising in an endometriotic cyst of the ovary is described. These two tumors are macroscopically polypous and are histologically a clear cell carcinoma and an endometrioid carcinoma, respectively. This is a rare neoplasm and its existence supports the general opinion that clear cell carcinoma and endometrioid carcinoma of the ovary are both müllerian in origin.