Choledochal Cyst

A choledochal cyst is a congenital anomaly of the duct (tube) that transports bile from the liver to the gall bladder and small intestine. The liver produces bile to help digest food. When a child has a choledochal cyst, a swelling of that duct, bile may back up in the liver. This can cause liver problems or inflammation of the pancreas (pancreatitis) because it blocks the main duct from the pancreas gland to the intestine. Children with choledochal cysts have a higher rate of cancer of the bile duct in adulthood. Early treatment can reduce these risks.

Choledochal cysts are rare: one in every 100,000 to 150,000 children in Western countries is born with choledochal cysts. Girls are four times more likely to be affected than boys. The condition is more common in East Asian countries, especially Japan, though researchers do not know why.

Choledochal cysts can form in the part of the bile duct inside of the liver (intrahepatic) or outside the liver (extrahepatic).

There are four basic types of choledochal cysts based on where they appear:

• Type 1 — a cyst of the extrahepatic bile duct, accounting for up to 90% of all choledochal cysts
• Type 2 — an abnormal pouch or sac opening from the duct
• Type 3 — a cyst inside the wall of the duodenum
• Type 4 — cysts on both the intrahepatic and extrahepatic bile ducts