DNA polymerase ε-mutant endometrial carcinosarcoma: A case report and literature review

DNA polymerase ε (POLE)-mutant endometrial carcinosarcoma (ECS) is a rare clinical lesion. The current study describes the diagnosis and treatment of a woman who presented with yellow vaginal discharge for >2 months; in addition, a literature review was conducted, and the clinical and pathological characteristics, treatment and prognosis of POLE-mutant ECS are discussed. Preoperative endometrial curettage was performed and the patient was diagnosed with poorly differentiated adenocarcinoma. Based on this finding, a total hysterectomy, bilateral adnexectomy and lymph node dissection were performed. A postoperative pathological examination revealed the morphological characteristics of a high-grade carcinosarcoma in the endometrial tumor. The results of immunohistochemical staining showed that the carcinoma was cytokeratin 7-positive (sarcoma, -) and both the carcinoma and sarcoma were vimentin-positive (carcinoma, weak +; sarcoma, +). Additionally, TP53 showed aberrant immunohistochemical overexpression in the carcinoma and sarcoma, and the Ki-67 proliferation index was 80% in carcinosarcoma. Molecular testing revealed a c.1231G>T (p.Val411Leu) mutation in exon 13 of the POLE gene, and mutations in the TP53 gene were detected in exons 5, 6 and 8. Adjuvant therapy was not administered to the patient after surgery, and no recurrence/metastasis was detected during the 18-month follow-up period. These findings indicate that molecular subtyping should be performed routinely in ECS to identify the POLE-mutant subtype and to avoid overtreatment.