Cholangiolocellular Carcinoma Arising in a Normal Liver

A 65-year-old woman was found to have a solitary hepatic tumor measuring 18 mm in diameter on abdominal ultrasound. It showed peripheral enhancement in the arterial phase and enhancement retention in the delayed phase in an abdominal CT. At follow-up, 9 months later, the tumor had grown to 24 mm. Serum levels of CA19-9 had increased, but results for hepatitis B and C viruses were negative. Partial hepatectomy was performed. Histologically, the tumor was composed of dense proliferation of small irregular tubules with fibrous stroma. Immuno­histochemistry revealed the carcinoma cells to be positive for CK-7, CK-19, NCAM, negative for Hep-Par1, AFP, and EMA was strongly positive on the luminal surface of tubules. These findings are typical characteristics of well-differentiated cholangiolocellular carcinoma (CoCC). No features of chronic hepatitis were present. It is common for CoCC to have an underlying chronic hepatic disease as a background factor. It is very rare that the CoCC occurred in a normal liver.