Updates in diagnostic immunohistochemistry in endometrial carcinoma

Diagnostic difficulty in the morphologic assessment of endometrial carcinomas may arise in pathology practice. Challenges in tumor classification exist especially in the setting of high-grade carcinomas. These include FIGO grade 3 endometrioid, serous, clear cell, and undifferentiated carcinomas, in addition to carcinomas of mixed cell type and those exhibiting ambiguous morphologic features. This comprehensive review details key morphologic and immunophenotypic features of prototypic endometrial carcinomas, including a description of both well-established and novel immunohistochemical markers in the evaluation of these tumors. It also provides recommendations regarding prudent use of these ancillary techniques in distinguishing between various histologic subtypes of endometrial carcinoma that frequently result in persistent diagnostic problems.