Small cell neuroendocrine carcinoma expressing alpha fetoprotein in the endometrium

Rare small cell neuroendocrine carcinoma (SCNEC) cases showed alpha fetoprotein (AFP) expression in the endometrium. In this study, we reported a case of uterine SCNEC expressing AFP. In addition, a literature review was performed to investigate the potential mechanism and the clinicopathological features of SCNEC to provide clinical guidance. A 65-year-old female was referred to our hospital due to vaginal bleeding for 1 month in November 2020. The clinical features were summarized. After total hysterectomy and removal of bilateral appendages, the histological examination and immunohistochemistry examination were performed. Histological findings showed that the cancer cells were arranged in a nest-like pattern distributed in a lamellar manner. The smooth muscles of the uterus were invaded by cancer cells. Cancer cells were relatively consistent in size. Small glandular duct-like and rosettes-like structures were distinguished, together with necrotic tissues. The deep staining showed that the amount of cytoplasm was lower in the nucleus. Partial cancer cells had small nucleolus with an irregular profile. There were some mitotic figures. Immunohistochemistry examination indicated that there was a diffuse expression of CK, Syn, CgA, CD56, CK8/18, P16, AFP, HepPar-1, Glypican-3, and Ki67 (90%). In this case, we reported a SCNEC patient expressing AFP, Glypican-3, and HepPar-1.