[Pathology of cholangiocarcinoma]

Cholangiocarcinomas (CC) are tumors that arise from the epithelial cell of the biliary tract. They represent the second most frequent primitive liver malignancy after hepatocellular carcinoma. Recent epidemiological data show an increase incidence of CC independently of the increased incidence of cirrhosis. According to their location in the biliary tract, we distinguish intrahepatic, hilar (Klastkin tumors) and extrahepatic CC. In literature, confusion exists around hilar CC that are included, according series, to intrahepatic or extrahepatic CC. However, hilar CC share common clinical, morphological and therapeutic features with extrahepatic CC. So, OMS classification of digestive tumors defined two groups of CC: intrahepatic or peripheral CC which develop from small intrahepatic biliary duct beyond the second segmentation, and extrahepatic CC comprising hilar CC and tumors from common hepatic bile duct. In this chapter, we will describe the different gross features and histological characteristic of CC and will detail the major histopronostic criteria of these tumors.