Fig. 1.

Schematic representation of the anatomic subgroups of biliary tract cancer. The classification of the carcinomas is based on the anatomical localization of the primary tumor. Intrahepatic cholangiocarinomas (iCCA) originate from the intrahepatic bile tracts proximal to the left or right hepatic duct. Extrahepatic tumors (eCCA) are divided into perihilar (pCCA) and distal (dCCA) carcinoma. pCCA—also called Klatskin tumors—compromise tumors of the left and right hepatic ducts and the common hepatic duct. dCCA are localized distal to the estuary of the common hepatic duct into the common bile duct. Carcinoma of the gallbladder (GBC) and of the cystic duct are subentities