Definition

Bile duct cancer, or cholangiocarcinoma, is a malignant
tumor of the bile ducts within the liver (intrahepatic),
or leading from the liver to the small intestine (extrahepatic).
It is a rare tumor with poor outcome for most patients.

Description

Bile is a substance manufactured by the liver that
aids in the digestion of food. Bile ducts are channels that
carry the bile from the liver to the small intestine. Like
the tributaries of a river, the small bile ducts in the liver
converge into two large bile ducts called the left and right
hepatic ducts. These exit the liver and join to form the
common hepatic duct. The gallbladder, which concentrates
and stores the bile, empties into the common
hepatic duct to form the common bile duct. Finally, this
large duct connects to the small intestine where the bile
can help digest food. Collectively, this network of bile
ducts is called the biliary tract.

Bile duct cancer originates from the cells that line
the inner surface of the bile ducts. A tumor may arise
anywhere along the biliary tract, either within or outside
of the liver. Bile duct tumors are typically slow-growing
tumors that spread by local invasion of neighboring
structures and by way of lymphatic channels.

Bile duct cancer is an uncommon malignancy. In the
United States, approximately one case arises per 100,000
people per year, but it is more common in Southeast
Asia. It occurs in men only slightly more often than in
women, and it is most commonly diagnosed in people in
their 50s and 60s.

Causes and symptoms

A number of risk factors are associated with the
development of bile duct cancer: