Pathology of Endometrioid and Clear Cell Carcinoma of the Ovary

This review is an appraisal of the current state of knowledge of 2 enigmatic histotypes of ovarian carcinoma: endometrioid and clear cell carcinoma. Both show an association endometriosis and the hereditary nonpolyposis colorectal cancer (Lynch) syndrome, and both typically present at an early stage. Pathologic and immunohistochemical features that distinguish these tumors from high-grade serous carcinomas, each other, and other potential mimics are discussed, as are staging, grading, and molecular pathogenesis.