extrahepatic bile duct cancer (EK-struh-heh-PA-tik bile dukt KAN-ser)
A rare cancer that forms in the bile ducts outside the liver. A bile duct is a tube that carries bile (fluid made by the liver) between the liver and gallbladder and the small intestine. Cancer that forms in the area where the right and left bile ducts meet outside the liver is called Klatskin tumor. It is the most common type of bile duct cancer.