Cytologic features of hepatoid carcinoma of the ovary: a case report with immunocytologic evaluation of HepPar1.

Background Hepatoid carcinoma is a rare, primary neoplasm of the ovary characterized by histologic, immunohistochemical and analytical evidence of hepatic differentiation. Reflecting the rarity of this entity, few cytologic descriptions are available. Case A 65-year-old woman presented with an abdominopelvic mass, peritoneal implants and elevated levels of CA-125 and α-fetoprotein (AFP). Cytologic examination of the ascitic fluid revealed cellular samples of polygonal cells in trabecular and papillary groups. Neoplastic cells were predominantly monomorphous, but some groups exhibited marked cellular atypia. A few trabecular groups showed peripheral endothelial rimming. Histologically, the neoplasm had evident hepatocellular differentiation, with a solid, trabecular growth of polygonal, eosinophilic cells with well-defined boundaries. The cells were immunoreactive with keratins, AFP and HepParl. Retrospectively, HepParl was tested in cytologic samples, with a positive result. Conclusion As occurs with other hepatocellular neoplasms, the hepatic differentiation that characterizes this unusual neoplasm may not be easily recognizable in effusion samples. However, there are some features that, in addition to an elevated AFP value, may help to suggest the diagnosis. A predominant trabecular arrangement with occasional endothelial rimming and HepParl immunoreactivity, consistent with hepatic differentiation, are unusual in common surface epithelial ovarian tumors.