What Is Bile Duct Cancer?
Bile duct cancer (also known as cholangiocarcinoma) is a type of cancer that starts in a bile duct. It can start in any part of the bile duct system.
About the bile ducts
To understand bile duct cancer, it helps to know about the bile ducts and what they normally do.
Bile is a fluid made in your liver and stored in your gallbladder. Your bile ducts are a series of thin tubes that carry bile from your liver and gallbladder into your small intestine, where the bile helps digest the fats in food. Bile also helps your body get rid of waste material that is filtered out of the bloodstream by your liver.
Different parts of the bile duct system have different names. In the liver, the bile duct system begins as many tiny tubes (called ductules). The ductules come together to form small tubes called ducts. These small ducts merge into larger ducts and then merge again to form the left and right hepatic ducts. All of these ducts within the liver are called intrahepatic bile ducts.
The left and right hepatic ducts exit the liver and join to form the common hepatic duct. Bile ducts located outside the liver are called extrahepatic bile ducts.
The gallbladder is a small organ that stores bile. It is located below the liver. It is connected to the common hepatic duct via the cystic duct. These come together to form the common bile duct. The common bile duct passes through part of the pancreas before it joins with the pancreatic duct and empties into the duodenum (first part of the small intestine) at the Ampulla of Vater.
Types of bile duct cancers by location
Bile duct cancer (cholangiocarcinoma) can start in any part of the bile duct system. Depending on where the cancer starts, it is either an intrahepatic cholangiocarcinoma or an extrahepatic cholangiocarcinoma.
Intrahepatic cholangiocarcinoma
Intrahepatic bile duct cancers start in the smaller bile duct branches within the liver. They make up about 10% of all bile duct cancers. Sometimes, intrahepatic bile duct cancers are confused with hepatocellular carcinoma, a cancer that starts in the liver cells. But these are two different types of cancer, and they are treated differently.
Extrahepatic cholangiocarcinoma
There are two types of extrahepatic cholangiocarcinoma: perihilar duct cancer and distal duct cancer.
Perihilar bile duct cancers are found in the hilar region of the bile duct system. The hilar region is where the left and right hepatic ducts leave the liver and join to form the common hepatic duct. Perihilar duct cancers are also called Klatskin tumors.
Distal duct cancers are found along the common bile duct. The common bile duct starts where the common hepatic duct joins with the cystic duct (from the gallbladder) and extends through the pancreas and into the small intestine at the Ampulla of Vater.
Cancers that start in different parts of the bile ducts can cause different symptoms.
Types of bile duct cancer by cell type
Bile duct cancers can also be divided into types based on how the cancer cells look under the microscope.
Nearly all bile duct cancers are cholangiocarcinomas (a type of adenocarcinoma, which is a cancer that starts in gland cells). Cholangiocarcinomas start in the gland cells that line the inside of the ducts.
Other types of bile duct cancers are much less common. These include sarcomas, lymphomas, and small cell cancers. Our information does not cover these rare types of bile duct cancer.
Benign bile duct tumors
Not all bile duct tumors are cancer. For example, bile duct hamartomas and bile duct adenomas are types of benign (non-cancer) tumors.
Other cancers in the liver
The most common type of cancer that starts in the liver is hepatocellular carcinoma. This type of cancer starts in the main cells that make up the liver. It is more common than cholangiocarcinoma.
Cancers that start in other organs, such as the colon or rectum, can sometimes spread (metastasize) to the liver. These metastatic cancers are not true liver cancers. For example, colorectal cancer that has spread to the liver is still colorectal cancer, not liver cancer.
The treatment and outlook for cancer that metastasizes to the liver is not the same as for a cancer that starts in the liver. For this reason, it’s important to know whether a tumor in the liver started in bile ducts (cholangiocarcinoma), if it started in the liver tissue itself (hepatocellular carcinoma), or if it started in another organ and has spread to the liver.
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The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.
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National Cancer Institute. Bile Duct Cancer (Cholangiocarcinoma) Symptoms, Tests, Prognosis, and Stages (PDQ?)–Patient Version. May 24, 2024. Accessed at www.cancer.gov/types/liver/patient/about-bile-duct-cancer-pdq on August 19, 2024.
Patel T, Borad MJ. Carcinoma of the biliary tree. In: DeVita VT, Lawrence TS, Rosenberg SA, eds. DeVita, Hellman, and Rosenberg’s Cancer: Principles and Practice of Oncology. 10th ed. Philadelphia, PA. Lippincott Williams & Wilkins; 2015:715-735.
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Last Revised: October 11, 2024
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