Hilar/Perihilar Cholangiocarcinoma (Klatskin Tumor)

Abstract

Carcinoma of the extrahepatic bile ducts is defined as an adenocarcinoma arising in proximal, middle third, and distal (lower third) parts of extrahepatic ducts. As anatomically a division of the duct system into thirds is artificial, novel classifications distinguish perihilar/hilar cholangiocarcinomas from those of the mid-region and the distal part of the common bile duct. For the definition of perihilar cancers, the separation point between intrahepatic and extrahepatic tumors is defined by the level of second-order bile ducts. Bile ducts located to the hepatic plate of the hilum correspond to extrahepatic bile ducts. The growth patterns and associated clinical sequelae vary as a function of anatomical location. Perihilar/hilar tumor forms concentrically stenosing lesions (Klatskin tumors). Tumors in the mid-region more commonly present as tubular lesion with thickening of the duct wall, whereas distal tumor more often shows an exophytic growth pattern. Histologically, the neoplasms are adenocarcinomas of the cholangiocyte lineage, usually associated with abundant stroma (desmoplasia). The cancers have a strong tendency for perineural and intraneural invasion, extension along bile ducts, and lymphatic spread.