Introduction/Background Mixed endometrial carcinoma (MEC) refers to a tumor that is comprised of two or more distinct histotypes. Each component histotype by definition has to represent more than 5% of the tumor. Although it is relatively rare, both diagnosis and management can be troublesome. Molecular and histopathologic features have become important in the identifcation and more importantly the precise management of the MEC’s.

In our study, we aimed to evaluate the clinical and pathological characteristics of the MEC

Methodology The clinical and pathological records of the 29 MEC patients who were operated on and regularly followed up in the clinic between January 2000-December 2019 were reviewed. Clinical features, operation characteristics, pathological findings, myometrial invasion degree (MI), lymph node involvement (LNI), lymphovascular space invasion (LVSI), adjuvant therapies, and follow-up data of the patients and their effects on survival were investigated.

Results During the study period, 29 out of 1110 patients with endometrial cancer had MEC (2.6%). Eighteen of the cases had endometrioid + serous, 7 had endometrioid + clear, 3 had endometrioid + serous, and 1 had clear + serous histopathology. The mean age of the patients was 63.2±12.1. Laparoscopic surgery was performed in 8 of the cases (27.6%).Sixteen of the cases were in stage 1 (55.1%), 4 were in stage 2 (13.8%), and 9 were in stage 3 (31%). LVSI was positive in 17 cases (58.6%). LNI was detected in 7 cases (24.1%). Approximately 80 percent of cases received adjuvant therapy. While 80% of the cases received chemotherapy, this rate was 55% for radiotherapy.

Conclusion MECs are tumors that can be difficult to diagnose and manage. In addition to histopathological features, revealing and evaluating their molecular properties will help us to better understand this group of tumors.

Disclosures None