Combined hepatocellular and cholangiocarcinoma with marked squamous cell carcinoma components arising in non-cirrhotic liver.

We report a surgical case of liver tumor, 40 x 35 mm in size, with squamous cell carcinoma (SCC) and hepatocellular carcinoma (HCC) components in a 60-year-old Japanese man with steatohepatitis. Most of the SCC component showed typical intercellular bridge and keratinization, while most of the HCC components showed a thick trabecular pattern with mild to moderate nuclear atypia. Both components transit each other without undifferentiated foci; however, a small foci showing glandular structure was intermediated. No cyst formation was found in the liver. The primary site of the squamous cell carcinoma was not detected in general clinical and radiological examination. Immunohistochemical analysis revealed that part of the HCC components neighboring the SCC showed patchy and weak expression of cytokeratin 7. There are several possibilities for the origin of squamous cell carcinoma in this case: marked squamous metaplastic change of cholangiocarcinoma and/or HCC, and carcinoma originating from pleuripotential stem cells. Irregular fatty changes, scattered giant mitochondria and acellular fibrosis with bridging were seen in the liver; however, this patient had no episode of hepatitis-associated viral infection. This is an interesting case of combined hepatocellular and cholangiocarcinoma with marked SCC components arising in a non-cirrhotic fibrotic liver.