Tripartite components of a hepatocellular carcinoma with distinct immunohistochemical and metastatic features.

We report an unusual case of hepatocellular carcinoma with three histologically and immunohistochemically distinct components, arising in a noncirrhotic liver, with a pulmonary tumor embolus from one of the three components. The histological patterns of the three components were fibrolamellar, well-differentiated nodular, and pleomorphic. The immunophenotypes were, respectively CK7- /CK20- /Hep Par1+, CK7+ /CK20- /Hep Par1+, and CK7+ /CK20+ /Hep Par1-. The tumor in the pulmonary embolus showed only the morphological and immunohistochemical features of the pleomorphic component. This unusual case ofmetastasizing hepatocellular carcinoma with three distinct histologic components suggests that the histological and immunophenotype of the tumor might be useful in predicting metastatic potential.