Bile duct cancer begins when normal cells in the bile duct change and grow uncontrollably, forming a mass called a tumor. A tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can spread to other parts of the body. A benign tumor means the tumor will not spread.
About the bile duct
The bile duct is a 4-inch to 5-inch long tube that connects the liver and gallbladder to the small intestine. The bile duct allows bile, which is made in the liver and stored in the gallbladder, to flow into the small intestine. Bile is a liquid that helps to break down fats found in foods and helps the body get rid of the waste material that is filtered out of the bloodstream by the liver.
The bile duct starts in the liver. Within the liver, smaller tubes, similar to small blood vessels, drain bile from the cells in the liver into larger and larger branches, ending in a tube called the common bile duct. The end of the bile duct empties into the small intestine.
The gallbladder is a reservoir that holds bile until food reaches the intestines. It is attached by a small duct, called the cystic duct, to the common bile duct. This attachment occurs about one-third of the way down the bile duct from the liver.
Types of bile duct cancer
Cancer can occur in any part of the bile duct. For bile duct cancer, doctors look at the exact location of the tumor:
Extrahepatic. The part of the bile duct that is located outside of the liver is called extrahepatic. Cancer usually begins in this part of the bile duct. A common site for bile duct cancer is the point where the right and left hepatic ducts join. A tumor that starts in this area is also sometimes called a Klatskin’s tumor. The rest of the bile duct cancers that begin outside the liver occur between the place where the right and left hepatic ducts meet and the place where the bile duct empties into the small intestine.
Intrahepatic. About 5% to 10% of bile duct cancers are intrahepatic, meaning they are located inside the liver.
This section is about primary bile duct cancer, which is cancer that starts in the bile duct. For information about cancer that began in another part of the body and spread to the bile duct, please see Cancer.Net’s guide for that type of cancer.