[A case of cholangiolocellular carcinoma found to be hepatic hemangioma at 16-month follow up].

We report a rare case of hepatic cholangiolocellular carcinoma (CoCC) with long-term observation. A 73-year-old woman was found to have a solitary hepatic tumor with a diameter of 10mm on dynamic computed tomography (CT), which showed peripheral enhancement in the arterial phase and enhancement retention in the delayed phase. Although it was initially diagnosed as hepatic hemangioma, the follow up examination conducted 16 months later revealed that the tumor had grown to 18mm. Doubling time of the tumor was calculated to be 177 days. Because magnetic resonance imaging results were not typical for hepatic hemangioma, hepatocellular carcinoma was suspected and partial hepatectomy was performed. Histologically, the tumor was comprised dense proliferation of small irregular tubules with fibrous stroma. Immunohistochemistry revealed that the carcinoma cells were positive for cytokeratin (CK) 7, CK19, and neurnal cell adhesion molecule. Cells were negative for hepatocyte paraffin 1. Periodic acid-Schiff and Alcian blue staining showed an absence of mucin in the tumor cells, and epithelial membrane antigen was strongly positive on the luminal surface of tubules. These findings were typical of CoCC;therefore, CoCC should be ruled out when dynamic CT images suggest hepatic hemangioma.