A rare case report of mandibular metastasis of hepatocellular carcinoma: autopsy, immunohistochemical, and ultrastructural examination with literature review

Abstract

A rare case of hepatocellular carcinoma (HCC) that metastasized to the posterior mandible of a 74-year-old Japanese female is described. Computed tomography (CT) revealed buccolingual osteolytic masses. Histopathologically, the solid tumor nests were composed of cells with granular eosinophilic cytoplasm, oval nuclei and enlarged nucleoli. Immunohistochemically, the tumor cells were strongly positive for hepatocyte paraffin 1 (Hep Par 1) and cytokeratin 18 (CK18). Ultrastructurally, abundant mitochondria, rough endoplasmic reticulum, lysosome-like granules, ductal structures and intercellular junctional complexes were distinct in the tumor cells. At autopsy, multinodular tumor masses and cirrhosis were detected in the liver. Microscopically, the tumor cells had trabecular, solid and sarcomatous appearances with severe atypism. Metastatic foci were found in the spleen, stomach, lymph nodes and ribs, but not in the lungs. We finally diagnosed this as mandibular metastasis of HCC, which is a very rare cancer, 1 of only 5 known cases in a female.