Digestive and Gastrointestinal Conditions

Choledochal Cyst

What Is Choledochal Cyst?

Choledochal cyst is a problem with the tubes (ducts) that carry bile from your child's liver to their gallbladder and intestine. The tubes get bigger than normal (dilate), or pouches form on the tubes. This keeps bile from flowing well, which can cause liver problems.

Bile is a liquid that helps the body break down (digest) fats. Normally, bile flows through tiny bile ducts within the liver into larger ducts. Then bile leaves the liver through two main ducts. Outside the liver, these ducts join to form the common bile duct.

The common bile duct connects the liver to the gallbladder and the gallbladder to the small intestine. The gallbladder stores bile until the body needs it to digest food. Food triggers the gallbladder to contract and squeeze bile out into the intestine.

Cysts can block the flow of bile. When bile doesn't flow well, the bile ducts can get swollen and irritated (inflamed) or infected. This is called cholangitis. Over time, it can cause scars in the liver (cirrhosis). Then the liver cannot work well. Children with choledochal cysts may also get an inflamed pancreas (pancreatitis).

Choledochal Cyst in Children

Choledochal cyst is present at birth (congenital). It happens while a baby is forming, before they are born.

Doctors aren't sure why cysts form. One reason may have to do with the pancreas. Normally, a duct from the pancreas joins with the common bile duct right before it goes into the small intestine. Muscle in the wall of the intestine keeps pancreas juices from flowing up into the bile duct. In some babies, the duct from the pancreas joins with the common bile duct higher up. So the muscle cannot keep the pancreas juices out of the bile duct. Instead, the juices flow up the common bile duct. They damage and weaken the wall of the duct as it forms.

There are five main types of choledochal cysts. The type is based on where the cyst is in the ducts and what shape the cyst has.

  • In type I, the common bile duct dilates, or expands. It looks more like a small balloon than a tube. About 9 out of 10 cysts are type I.
  • In type II, a pouch (diverticulum) forms off of the common bile duct.
  • In type III, the bottom end of the duct dilates inside the small intestine. This is sometimes called choledochocele.
  • In type IV, the bile ducts inside the liver and outside the liver dilate.
  • In type V, the large ducts inside the liver dilate, and the ducts outside the liver are normal. This type is also called Caroli disease.

Girls are three to four times as likely as boys to have choledochal cysts. Babies of Eastern Asian descent (including Southeast Asian descent) are more likely to have cysts than babies from other family backgrounds. These two factors suggest that genes passed from parents to babies (especially genes passed to girls) might be one cause of cysts. But having one baby with a cyst does not mean you will have another baby with the same problem. Other factors besides genes must play a part too.

People who have had choledochal cysts have a higher chance of getting cancer of their bile ducts (cholangiocarcinoma). This mainly affects adults with cysts, because they have had their cysts for many years. The chance of getting cancer is much lower if cysts are removed early in life.

Choledochal Cyst at Seattle Children's

We have treated many babies as well as older children with choledochal cysts at Seattle Children's. Our surgeons are experienced at performing the surgeries these children need to remove their cyst and create good bile flow.

When you come to Seattle Children's, you have a team of people to care for your child. Along with your child's surgeon, you are connected with nurses, dietitians, child life specialists and others. We work together to meet all of your child's health needs and help your family through this experience.

Since 1907, Seattle Children's has been treating children only. Our team members are trained in their fields and also in meeting the unique needs of children. For example, the doctors who give your child anesthesia are board certified in pediatric anesthesiology. This means they have extra years of training in how to take care of kids. Our child life specialists know how to help children understand their illnesses and treatments in ways that make sense for their age. Our expertise in pediatrics truly makes a difference for our patients and families.