Combined large-cell neuroendocrine carcinoma and endometrioid adenocarcinoma of the endometrium: A case report

Abstract

Objective: Large cell neuroendocrine carcinoma (LCNEC) of the endometrium is a relatively rare and usually aggressive malignancy. We report a case of an endometrial tumour that was a combination of a LCNEC and endometrioid adenocarcinoma. Method: A 58-year-old woman presented with postmenopausal vaginal bleeding. Explorative curettage revealed a LCNEC of the endometrium. She underwent total abdominal hysterectomy with bilateral salpingooophorectomy and was diagnosed as having FIGO stage IB endometrial carcinoma. In spite of refusal of adjuvant therapy, and irregular follow-up, she has been well with no evidence of disease for 52 months following surgery. Results: Grossly, a polypoid neoplasm measuring 6.5 × 2.2 × 2.5 cm, infiltrating more than a half of the thickness of the myometrium of the posterior uterine wall was found. Histologically, the tumour was composed of two components: a predominant large cell high-grade neuroendocrine carcinoma and a minor superficial well-differentiated endometroid adenocarcinoma with foci of squamous differentiation. There was a differential immunoreactivity between the two components. More than 10 % of the cells of the LCNEC were positive for three neuroendocrine markers (CD56, NSE and synaptophysin), showing also diffuse positivity for cytokeratin 18, vimentin, and p16, and hormone receptor negativity, whereas the majority of the cells of endometroid carcinoma were negative for neuroendocrine markers, hormone receptor positive and only focally p16 positive. The proliferative index determined by Ki-67 was higher in LCNEC in which p53 overexpression was also present. Conclusion: Immunohistochemical analysis is helpful in diagnosing and differentiating primary LCNEC. The presented case also confirms that early-stage polypoid LCNEC may have a more favourable prognosis.