Cholangiolocellular carcinoma containing hepatocellular carcinoma and cholangiocellular carcinoma, extremely rare tumor of the liver:a case report.

Cholangiolocellular carcinoma (CLC) is an extremely rare malignant liver tumor which was first defined by Steiner, et al. in 1957 (1). CLC is thought to be derived from Hering's canal because tumor glands of CLC are morphologically similar to cholangioles. Recently, Theise, et al. reported that Hering's canal might be composed of hepatic stem cells (3). In addition, CLC sometimes contains a hepatocellular carcinoma (HCC) or cholangiocellular carcinoma (CCC) component within the tumor. Those findings suggest that CLC might originate from hepatic stem cells. On the other hand, because of its low frequency, clinicopatholigical features of CLC have not been fully clarified yet. We herein report a case of a 71-year old man with CLC. Based on preoperative imagings, the hepatic tumor was diagnosed as HCC, and he underwent a partial hepatectomy. The tumor contained both a HCC and CCC-like area. In immunohistochemistry, cytokeratin (CK) 7, CK20, CAM5.2 was positive, and CK19 was negative, therefore the tumor was diagnosed as CLC. The diagnostic criteria have not been described clearly, so CLC is difficult to diagnose preoperatively. Further studies are needed to clarify the clinical and clinicopatholigical features of CLC.