What are choledochal cysts?
Choledochal cysts are also known as bile duct cysts. They are rare, congenital cysts, which means a child is born with them. The majority appear before age 10. They occur in girls more often than boys.
Symptoms usually include jaundice, abdominal pain and a palpable (able to be felt from the outside) mass in the abdomen. However, these three symptoms are only present in about 40 percent of cases, with palpable mass being the least common symptom.
There are five main types of choledochal cysts.
- Type I: These are the most common, accounting for 80 to 90 percent of cases. They can appear in babies before birth.
- Type II: A diverticulum (a pouch or sac that appears inside a canal) from the extrahepatic (outside the liver) bile duct
- Type III: An opening of the extrahepatic bile duct within the duodenal wall
- Type IV: This is the second most common type of choledochal cyst. They are like the other three types, but involve ducts inside and outside the liver, and multiple kinds of duct dilatation.
What causes choledochal cysts?
Experts aren't sure exactly what causes these cysts. Some possible reasons are:
- An infection after birth
- An immune system problem, such as when the immune system attacks the liver or bile ducts for unknown reasons
- A genetic mutation. This is a long-lasting change in a gene’s structure.
- A problem during liver and bile duct development in the fetus
- Contact with toxic substances
How are they diagnosed?
In most cases, congenital liver defects that affect the flow of bile are diagnosed at birth or soon after. Your child’s healthcare provider will take a full health history and do a physical exam. Your child may also have tests, which may include ultrasound, CT, ERCP or MRI.
How we treat choledochal cysts
If your child has a choledochal cyst, he or she must have surgery to remove the cyst and allow normal bile flow. The type of surgery will depend on where the cyst is located, as well as other factors.