Cholangiocarcinoma is a diverse group of rare but highly fatal malignancies arising from the biliary tract epithelium. According to their anatomical origin in the biliary tract, cholangiocarcinomas can be subdivided into three distinct categories, namely intrahepatic, perihilar, and distal cholangiocarcinoma. Besides definitional purposes, considering each category of different biologic characteristics and clinical course, such a classification is useful in diagnostic approach and clinical management.
In this chapter, epidemiology, clinical presentation, available diagnostic modalities, and finally staging and clinical management of perihilar cholangiocarcinoma are discussed. Intrahepatic cholangiocarcinoma and distal cholangiocarcinoma are discussed separately.
ANATOMIC CLASSIFICATION AND HISTOPATHOLOGY
Cholangiocarcinoma was first reported by Durand-Fardel in 1840 and originally referred only to primary tumors of the intrahepatic bile ducts.1-3 More recently, the term "cholangiocarcinoma" has been used to refer to all primary tumors arising from the malignant proliferation of the epithelial cells lining the biliary tract, including both intrahepatic and extrahepatic ducts.4
Cholangiocarcinomas are classified according to their anatomical origin as intrahepatic (located proximally to the second-degree branches of left and right bile ducts within the liver), perihilar (confined to the area between the second-degree bile ducts and the insertion of cystic duct into the common bile duct), or distal cholangiocarcinoma (localized within the pancreatic portion of the common bile duct, distal to the insertion of the cystic duct).4,5 Perihilar cholangiocarcinoma, first described by Klatskin in 1965,6 can be further subdivided into four types (Bismuth–Corlette classification) based on the distribution of the bile duct involvement7,8 (Fig. 133-1). The term “Klatskin tumor” or hilar cholangiocarcinoma (HC) typically refers to tumor involving the common hepatic duct bifurcation.
Classification of cholangiocarcinoma. A. The classification of cholangiocarcinoma can be based on anatomic location: intrahepatic, hilar, or extrahepatic. B. Lesions can be further characterized as mass-like, periductal, or intraductal. C. Bismuth classification for hilar lesions.8 Type I, involvement of hepatic duct below the bifurcation; Type II, involvement of bifurcation without invasion of second-order ducts; Type IIIa, involvement of right-sided ducts into second order, but with sparing of left second-order ducts; Type IIIb, involvement of left-sided ducts into second order, but with sparing of right second-order ducts; Type IV, involvement of bilateral second-order ducts (IVa) and/or skip lesions (IVb).
Most cholangiocarcinomas are adenocarcinomas (>90%), with rare occurrence of other histologic subtypes (i.e., squamous cell carcinoma, signet-ring carcinoma, papillary adenocarcinoma, etc.), and can be graded as well-, moderately, or poorly differentiated tumors (more commonly well- and moderately differentiated).9-12 Macroscopically, the three distinct subtypes of cholangiocarcinoma include sclerosing, nodular, and papillary.13,14 The majority of perihilar cholangiocarcinomas are sclerosing tumors that are characterized by annular thickening of the bile duct, extensive fibrosis of periductal tissues, and a dense desmoplastic reaction....