According to Bismuth classification, type IV cholangiocarcinoma involves:
Bismuth-Corlette Classification of Hilar Cholangiocarcinoma Type Criteria I Tumor confined to hepatic duct, not involving the main biliary confluence II Tumor involving the main biliary confluence but not extending to the right or left ducts IIIa Tumor extending upto the right secondary biliary confluence IIIb Tumor extending upto the left secondary biliary confluence IV Tumor extending bilaterally to the secondary biliary confluence Most common site of cholangiocarcinoma is Hilum
Common hepatic duct
Bifurcation only
Bifurcation and bilateral secondary intrahepatic duct
Bifurcation and unilateral secondary intrahepatic ducts
Bile duct