General Information About Extrahepatic Bile Duct Cancer
Extrahepatic bile duct cancer is a rare disease in which malignant (cancer) cells form in the part of bile duct that is outside the liver.
A network of bile ducts (tubes) connects the liver and the gallbladder to the small intestine. This network begins in the liver where many small ducts collect bile, a fluid made by the liver to break down fats during digestion. The small ducts come together to form the right and left hepatic bile ducts, which lead out of the liver. The two ducts join outside the liver to become the common hepatic duct. The part of the common hepatic duct that is outside the liver is called the extrahepatic bile duct. The extrahepatic bile duct is joined by a duct from the gallbladder (which stores bile) to form the common bile duct. Bile is released from the gallbladder through the common bile duct into the small intestine when food is being digested.
Anatomy of the extrahepatic bile duct. The extrahepatic bile duct is part of a network of small ducts in the liver that collects bile. Bile flows into the right and left hepatic ducts which join together to form the common hepatic duct. The extrahepatic bile duct is the part of the common hepatic duct that is outside the liver. Bile flows through the extrahepatic bile duct and into the cystic duct to the gallbladder where it is stored. When food is being digested, bile flows back through the cystic duct and into the common bile duct where it is released into the small intestine.
Having colitis or certain liver diseases can increase the risk of developing extrahepatic bile duct cancer.
Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. People who think they may be at risk should discuss this with their doctor. Risk factors include having any of the following disorders:
- Primary sclerosing cholangitis.
- Chroniculcerative colitis.
- Choledochal cysts.
- Infection with a Chinese liver fluke parasite.
Possible signs of extrahepatic bile duct cancer include jaundice and pain.
These and other symptoms may be caused by extrahepatic bile duct cancer or by other conditions. A doctor should be consulted if any of the following problems occur:
- Jaundice (yellowing of the skin or whites of the eyes).
- Pain in the abdomen.
- Itchy skin.
Tests that examine the bile duct and liver are used to detect (find) and diagnose extrahepatic bile duct cancer.
The following tests and procedures may be used:
- Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments will also be taken.
- Ultrasound exam: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. The picture can be printed to be looked at later.
- CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography. A spiral or helical CT scan makes detailed pictures of areas inside the body using an x-ray machine that scans the body in a spiral path.
- MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
- ERCP (endoscopic retrograde cholangiopancreatography): A procedure used to x-ray the ducts (tubes) that carry bile from the liver to the gallbladder and from the gallbladder to the small intestine. Sometimes bile duct cancer causes these ducts to narrow and block or slow the flow of bile, causing jaundice. An endoscope is passed through the mouth, esophagus, and stomach into the first part of the small intestine. An endoscope is a thin, tube-like instrument with a light and a lens for viewing. A catheter (a smaller tube) is then inserted through the endoscope into the pancreatic ducts. A dye is injected through the catheter into the ducts and an x-ray is taken. If the ducts are blocked by a tumor, a fine tube may be inserted into the duct to unblock it. This tube (or stent) may be left in place to keep the duct open. Tissue samples may also be taken and checked under a microscope for signs of cancer.
- PTC (percutaneous transhepatic cholangiography): A procedure used to x-ray the liver and bile ducts. A thin needle is inserted through the skin below the ribs and into the liver. Dye is injected into the liver or bile ducts and an x-ray is taken. If a blockage is found, a thin, flexible tube called a stent is sometimes left in the liver to drain bile into the small intestine or a collection bag outside the body.
- Biopsy: The removal of cells or tissues so they can be viewed under a microscope to check for signs of cancer. The sample may be taken using a thin needle inserted into the duct during an x-ray or ultrasound. This is called a fine-needle aspiration (FNA) biopsy. The biopsy is usually done during PTC or ERCP. Tissue may also be removed during surgery.
- Liver function tests: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by the liver. A higher than normal amount of a substance can be a sign of liver disease that may be caused by extrahepatic bile duct cancer.