Adult-type hepatocellular carcinoma in the center of a fibrolamellar hepatocellular carcinoma.

A large hepatic tumor was detected in the noncirrhotic liver of a 27-year-old female patient. The tumor was radiologically characterized by a peripheral mass encircling a central ovoid tumor, and was resected by an extended right hemihepatectomy. Histologic examination revealed that the peripheral and major component of the tumor represented a fibrolamellar hepatocellular carcinoma, whereas the central, well-demarcated tumor was a less well-differentiated adult-type hepatocellular carcinoma completely encircled by the former. Cells of the peripheral tumor mass abundantly expressed cytokeratin-7, typically present in the fibrolamellar variant, whereas no cytokeratin-7 immunoreactivity was found in the central tumor. To our knowledge, this is the first reported case of a not admixed but clearly separated evolution of these 2 histologic patterns within the same tumor, and suggests that the 2 types of hepatocellular carcinoma may share a common pathogenic pathway.