Combined hepatocellular-cholangiocarcinoma with variable sarcomatous transformation.

An adult case of combined hepatocellular-cholangiocarcinoma with variable sarcomatous changes is presented. Histologically, the tumor was composed of hepatocellular carcinoma, cholangiocarcinoma, and sarcomatous portions, including spindle-shaped, pleomorphic, and osteoplastic varieties. There was a transitional cell form between the carcinoma and sarcomatous cells. These tumor elements showed both independent and concurrent metastases. Immunohistochemical examination for keratin revealed positive staining in the tumor cells except for osteoplastic immature cells, whereas vimentin had positive results only in some sarcomatous cells. On the basis of these findings, the possibility of sarcomatous transformation of combined hepatocellular-cholangiocarcinoma was discussed.