Tumors of the biliary tract are a heterogeneous and diverse group, which includes both benign and malignant conditions that develop within the biliary tract (Boxes 46.1 and 46.2). These can occur throughout the biliary tract, from the ampulla of Vater to the intrahepatic ductules, and including the gallbladder. Biliary tract tumors vary in their presentation, natural history, and management (Box 46.3).

Benign tumors of the biliary tract are uncommon, and usually present as biliary tract strictures or masses within the lumen of the bile duct that can mimic and need to be distinguished from malignancies. Some benign tumors may have malignant potential, or they may present as polyps or strictures and resemble cancers. Benign tumors in the biliary tract with malignant potential include biliary cystadenomas and biliary papillomatosis. Benign tumors of the gallbladder may present as luminal masses that need to be distinguished from gallstones or malignancies. The most common types of benign tumors in the gallbladder can present as polyps. Most of these are benign pseudopolyps, such as cholesterol polyps, focal adenomyomatosis, or inflammatory pseudopolyps. True polyps occurring in the gallbladder can be benign adenomas or malignant adenocarcinomas.

The main types of biliary tract cancers are (1) cholangiocarcinomas, arising from the intrahepatic and extrahepatic bile ducts; (2) gallbladder cancer, arising from the gall bladder and cystic duct, and (3) ampullary cancers, arising from biliary epithelia at the ampulla of Vater (see Box 46.2). Cholangiocarcinomas are cancers of the biliary tract that are associated with the intrahepatic or extrahepatic bile ducts. They are anatomically classified into intrahepatic, perihilar, and distal cholangiocarcinoma. These three types need to be distinguished as they are distinctively different tumors that vary in their clinical presentation, molecular pathogenesis, behavior, and management. Selected features on diagnostic imaging are shown in Figures 46.1, 46.3–46.5, 46.7, 46.8, 46.10, and 46.11. Suggested approaches for the diagnosis and management of each one of these cancers are outlined in Figures 46.2, 46.6, and 46.9.

Cholangiocarcinomas arising from the intrahepatic biliary tract beyond the second‐order ducts are termed intrahepatic cholangiocarcinoma. Cholangiocarcinomas occurring in the common hepatic duct beyond the papilla, and extending up to the junction with the cystic duct are termed distal extrahepatic cholangiocarcinoma. Cancers arising between the second‐order ductal division within the liver and the large extracellular ducts up to the confluence with the cystic duct are termed perihilar cholangiocarcinoma. Even though perihilar cholangiocarcinomas are amongst the most common malignancies of the biliary tract encountered in many parts of the world, these tumors are often inconsistently categorized as extrahepatic or intrahepatic cholangiocarcinoma. A distinction between perihilar cholangiocarcinoma and nonhilar distal cholangiocarcinoma is appropriate because of their distinctive presentation, staging, and treatment.

The diagnosis of these cancers is often challenging because they may present with nonspecific symptoms. When CCA is suspected, assessment includes imaging with ultrasound, computed tomography or magnetic resonance imaging, as well as biopsy, histology or cytology for diagnosis. If a diagnosis is not confirmed pathologically, change in growth and spread to distant sites with metastases may support the presence of malignancy. Staging with ¹⁸F‐fluorodeoxyglucose positron emission tomography (¹⁸FDG‐PET) may be useful for the detection of lymph node and distant metastases or for assessment of tumor recurrence if this would impact on management and other imaging studies were equivocal.

Other cancers arising from the biliary tract epithelia are gallbladder cancer (Box 46.4) and some ampullary cancers but these are not designated as cholangiocarcinoma. Periampullary tumors can arise from pancreatic, duodenal, or ampullary tissues. In most instances, the tissue of origin is obscure or requires pathological examination after excision. Distal CCA can occasionally present as periampullary tumors. The presentation, evaluation, and management of periampullary tumors of biliary tract origin are identical to those of any of the other types of periampullary tumors, namely pancreatic, duodenal, or ampullary tumors (see Chapter 27).