Primary hepatoid adenocarcinoma of the uterine corpus: A case report with immunohistochemical study for expression of liver-enriched nuclear factors.

We report a case of hepatoid adenocarcinoma of the uterus in an 86-year-old woman. Serum AFP was elevated (7824ng/ml) on admission. The surgical specimen obtained by simple hysterectomy and bilateral salpingo-oophorectomy showed an exophytic tumor, 10.5cm×6.0cm×3.7cm in size, in the uterine corpus. Microscopically, tumor cells proliferated in trabecular or cord-like arrangement, which was considered as "hepatoid appearance". An adenocarcinomatous component was intermingled. The expressions of liver-enriched transcription factors, hepatocyte nuclear factor (HNF)-1β, HNF-3, HNF-4α, and CCAAT/enhancer binding protein (C/EBP)-β, were investigated in the present case and in 19 cases of endometrioid adenocarcinoma (11 cases of Grade 2 and 8 cases of Grade 3), because these nuclear factors are involved in embryonal hepatogenesis. HNF-4α was diffusely positive in the present case, but negative in all cases of endometrioid adenocarcinoma. HNF-3 and C/EBP-β were positive for the present case and control adenocarcinoma cases (HNF-3, 36.8% and C/EBP-β, 84.2%). HNF-1β was negative for both the present case and endometrioid adenocarcinomas. This is the first report to demonstrate HNF-4α expression in this rare uterine tumor.