Hepatoid Carcinoma of the Ovary: Clinical, Histopathologic, and Immunophenotypic Features.

Hepatoid carcinoma of the ovary (HCO) is a rare malignant tumor of uncertain histogenesis that was first described by Ishikura and Scully in the late 1980s. Unlike hepatoid yolk sac tumor (HYST), one of its main differential diagnoses, HCO usually presents in perimenopausal and postmenopausal women without gonadal dysgenesis. Most cases show advanced local disease at initial presentation, with diffuse intraperitoneal dissemination. Despite aggressive treatment, including surgery and adjuvant chemotherapy, 61.5% of patients either die of the disease (11 of 26; 42.3%) or are alive with recurrent or residual disease (5 of 26; 19.2%) after a median follow-up of 11.5 months (range, 1-60 months). Most HCOs are solid, with high-grade histology, significant nuclear pleomorphism, scattered giant cells, and a high mitotic index. Their immunophenotype is defined by the expression of broad-spectrum cytokeratins, α-fetoprotein, and hepatocellular antigens with absence of sex cord and germ cell markers. Although immunohistochemistry can be very helpful to distinguish between sex cord-stromal tumors and HCO, differentiation of the latter from HYST, metastatic hepatocellular carcinoma, and metastatic gastrointestinal tumors with hepatoid phenotype requires integration of clinical, radiologic, and pathologic information.