Introduction/Background High grade endometrial carcinomas include serous carcinomas, clear cell carcinomas, FIGO grade 3 endometrioid carcinomas, undifferentiated carcinomas, and carcinosarcomas. Often the morphologic and immunohistochemical profile overlap significantly, with interobserver reproducibility in subtyping high-grade endometrial carcinomas is suboptimal. In patients with serous and clear cell carcinomas compared with those with grade 3 endometrioid, poor outcomes were reported. Undifferentiated carcinomas and carcinosarcomas are also well known as highly aggressive. So, distinguishing this tumor from FIGO grade 3 endometrioid carcinoma is of clinical importance. The aim of our study was to determine if there are significant differences regarding histotyping without and with the use of a panel of immunohistochemical markers.

Methodology One hundred sixty-eight patients admitted in the Gynecological Department of Emergency Hospital of Oradea were diagnosed with endometrial carcinomas over a 2-year period (2020–2021) on curettage specimen. Immunohistochemical staining of ER, PR, p16, p53, Napsin A, PAX8, E-Cadherin was performed in selected cases.

Results Out of 168 cases, 51 patients (30.35%) had high grade endometrial carcinomas. Among these, by using only morphological examination, we diagnosed 26 cases (50.98%) as serous carcinomas, 14 cases (27.45%) as FIGO grade 3 endometrioid carcinomas, 5 cases (9.8%) as clear cell carcinomas, 4 cases (7.84%) as carcinosarcomas and only 2 cases (3.92%) as undifferentiated carcinomas. Following immunohistochemical tests, we determined that 28 cases (54.9%) were serous, 12 cases (23.52%) were endometrioid, 3 cases (5.88%) were clear cell, 4 cases (7.84%) were undifferentiated carcinomas.

Conclusion In our cohort, 4 cases were misdiagnosed (2 clear cell carcinomas were actually serous carcinomas; and 2 FIGO grade 3 endometrioid carcinomas was reclassified as undifferentiated carcinomas). The accuracy of diagnosis increased from 92.15 to 100%, underlying the utility of ancillary tests which should be performed in conjunction with careful histologic evaluation.