What is Bile Duct Cancer?

The bile ducts are thin tubes that carry bile from the liver and gallbladder to the small intestine. Bile is a substance that helps the body digest food. Bile is made in the liver and stored in the gallbladder. As food is being digested, bile is released from the gallbladder and travels through the bile duct to the small intestine, where it helps the body break down food.

The bile duct begins inside the liver as many small tubes called ductules, which collect bile from the liver. These ductules merge together inside the liver and eventually exit the liver as two larger ducts, the left and right hepatic ducts.

Outside of the liver, the left and right hepatic ducts merge together to form the common hepatic duct. The gallbladder is connected to the common hepatic duct by the cystic duct. The common hepatic duct and the cystic duct merge to form the common bile duct. The common bile duct runs through the pancreas and empties bile into the small intestine through the ampulla of Vater.

Bile duct cancer is also known as Cholangiocarcinoma. Gallbladder cancer, on the other hand, is a separate cancer type. The vast majority of bile duct cancers on pathologic exams are found to be adenocarcinomas based upon their structure.The bile duct is a thin tube that carries bile from the liver and gallbladder to the small intestine. Bile is a substance that helps the body digest food. Bile is made in the liver and stored in the gallbladder. As food is being digested, bile is released from the gallbladder and travels through the bile duct to the small intestine, where it helps the body break down food.

Types of Bile Duct Cancer

There are different types of bile duct cancer, depending on where the cancer is located relative to the liver:

Extrahepatic

Extrahepatic bile duct cancer is cancer that begins in the portion of the bile ducts outside of the liver. This is the most common type of bile duct cancer, accounting for about 60% of all cases. There are two main types of extrahepatic bile duct cancer:

• Perihilar: Perihilar bile duct cancers develop at the hilum of the liver, or the area just outside of the liver where the left and right hepatic ducts merge together to form the common hepatic duct. These tumors are sometimes referred to as Klatskin tumors. They are the most common type of extrahepatic bile duct cancer and make up about 60-70% of all diagnoses.
• Distal: Distal bile duct tumors form in the common bile duct, closer to the pancreas and small intestine. These tumors account for about 20-30% of all extrahepatic bile duct cancer diagnoses.

Intrahepatic

Intrahepatic bile duct cancer begins in the small bile duct branches (ductules) inside the liver. These tumors account for about 40% of all bile duct cancers. Although rare, these tumors are becoming more and more common.