Cholangiocarcinoma is a malignant tumor that develops from the epithelial cells of the bile ducts. It can occur anywhere along the biliary system and is classified as intrahepatic, perihilar (at the junction of the right and left hepatic ducts, also called a Klatskin tumor), or distal, depending on its location. On ultrasound, cholangiocarcinoma may appear as a mass within or adjacent to the bile ducts, or it may present indirectly through its effects, such as dilated intrahepatic bile ducts without a visible gallstone to explain the obstruction. Identifying unexplained biliary dilation on ultrasound is an important finding that prompts further investigation with CT, MRI, or endoscopic procedures to locate the cause.
Sonography Term