Primary liver cancer with dual expression of hepatocyte and bile duct epithelial markers.

A 65-year-old Japanese man with chronic hepatitis C was found to have a hepatic tumor by ultrasonography. Both dynamic computed tomography and hepatic angiography showed a hypervascular tumor with a central defect. Since a diagnosis of hepatocellular carcinoma was made, transcatheter arterial embolization was performed. However, the tumor metastasized to systemic lymph nodes and the patient died 3 months after treatment. An autopsy was performed. Histologic examination of the hepatic tumor revealed that the peripheral part was completely necrotic and the central area was composed of strands of pleomorphic cells with focal gland formation surrounded by fibrosis. No production of mucin or bile was evident. The microscopic findings of metastatic lymph nodes were similar to those of the central portion of the hepatic tumor. Immunohistochemical strains of the hepatic tumor and lymph node metastases showed diffuse positivity for cytokeratins 7 and 19, while hepatocyte paraffin 1 was focally reactive. These findings suggest that the hepatic tumor was a combined hepatocellular carcinoma and cholangiocarcinoma. Since the tumor expressed dual phenotypic markers of both hepatocytes and bile duct cells, the tumor might have an intermediate phenotype between hepatocytes and bile duct cells.