There are two primary types of Biliary (Hepatobiliary) cancer: hepatocellular carcinoma, which refers to cancer than develops within the liver, and cholangiocarcinoma, which refers to cancer that develops within the liver's biliary ducts. Of these cancers, hepatocellular carcinoma is the most common.
Cholangiocarcinoma can be further categorized as either intrahepatic biliary duct cancer if the cancer develops within the ducts of the liver, or as extrahepatic biliary duct cancer if cancer occurs outside the liver, in the area that attaches the liver to the gallbladder.
In the United States, the most common cause of cholangiocarcinoma is primary sclerosing cholangitis (PSC), an inflammatory condition of either the intrahepatic or extrahepatic bile ducts. PSC is thought to be an autoimmune disease, which causes blockages within bile ducts within the liver. It may also cause cancer in the ducts as well as liver failure. (In Asia, cholangiocarcinoma most often develops in individuals after certain parasitic infections.)