Neuroendocrine carcinoma of the endometrium concomitant with Lynch syndrome: A case report

BACKGROUND: Large-cell neuroendocrine carcinoma (NEC) is an uncommon type of tumor that can occur in the endometrium. This aggressive cancer requires definitive management. Here, we describe the clinical characteristics and treatment of a postmenopausal woman with large cell NEC of the endometrium. CASE SUMMARY: A 55-year-old Asian female presented with a 1-year history of postmenopausal vaginal bleeding. Transvaginal ultrasound revealed a thickened endometrium (30.2 mm) and a hypervascular tumor. Computed tomography revealed that the tumor had invaded more than half of the myometrium and spread to the pelvic lymph nodes. The tumor marker, carcinoembryonic antigen, was elevated (3.65 ng/mL). Endocervical biopsy revealed high-grade endometrial carcinoma. She underwent radical hysterectomy, bilateral salpingo-oophorectomy, omentectomy, and bilateral pelvic and para-aortic lymph node dissection. Pathological examination revealed mixed neuroendocrine and endometrioid adenocarcinoma, pT2N0M0, grade 3, and International Federation of Gynecology and Obstetrics stage 2. Immunohistochemistry showed moderate estrogen and progesterone receptor expressions (20% and 1%, respectively), focal CD56 expression (NEC marker), positive staining for vimentin, p53 (wild type), and ki67 (90%), and loss of expression of PMS2 (Lynch syndrome marker). The patient received five cycles of cisplatin and etoposide after surgery. No recurrence was noted after 5 mo. CONCLUSION: We report the characteristics and successful management of a rare case of large-cell endometrial NEC concomitant with Lynch syndrome.