Pathophysiology
Cholangiocarcinoma is a tumor that arises from the intrahepatic or extrahepatic biliary epithelium. More than 90% are adenocarcinomas, and the remainder are squamous cell tumors. The etiology of most bile duct cancers remains undetermined. Long-standing inflammation, as with primary sclerosing cholangitis (PSC) or chronic parasitic infection, has been suggested to play a role by inducing hyperplasia, cellular proliferation, and, ultimately, malignant transformation. Intrahepatic cholangiocarcinoma may be associated with chronic ulcerative colitis and chronic cholecystitis.
Cholangiocarcinomas tend to grow slowly and to infiltrate the walls of the ducts, dissecting along tissue planes. Local extension occurs into the liver, porta hepatis, and regional lymph nodes of the celiac and pancreaticoduodenal chains. Life-threatening infection (cholangitis) may occur that requires immediate antibiotic intervention and aggressive biliary drainage.