Figure 1: Bismuth-Corlette classification of Klatskin tumor (type I, tumor involves the common hepatic duct distal to the biliary confluence; type II, tumor involves the biliary confluence; type IIIa, tumor involves the biliary confluence plus the right hepatic duct; type IIIb tumor involves the biliary confluence plus the left hepatic duct; type IV, multifocal or tumor involves the confluence and both the right and left hepatic ducts).