A carcinoma that arises from the intrahepatic biliary tree (intrahepatic cholangiocarcinoma) or from the junction, or adjacent to the junction, of the right and left hepatic ducts (hilar cholangiocarcinoma). Grossly, the malignant lesions are solid, nodular, and grayish. Morphologically, the vast majority of cases are adenocarcinomas. Signs and symptoms include malaise, weight loss, right upper quadrant abdominal pain, and night sweats. Early detection is difficult and the prognosis is generally poor.