Choledochal cyst

What is a choledochal cyst?

This term refers to congenital dilation of the main bile duct (which brings bile from the liver to the intestine) and/or of the intrahepatic bile ducts (in the liver).

The cyst can develop when the junction between the main bile duct and the pancreatic duct is too far from the intestine.

Pancreatic juices (which are irritating) then flow back to the liver through the common bile duct.

This phenomenon causes irritation and promotes the development of a cyst. Its occurrence is very rare, with an incidence in Europe of 1 case in 100,000 births, but the tendency is for it to occur more frequently.

What are the symptoms?

In a small child a choledochal cyst can cause painful abdominal crises or pancreatitis (inflammation of the pancreas), or yellowing of the skin (jaundice), or even the formation of a mass in the right side of the abdomen.
Consequences over the very long term may be biliary cirrhosis (shrinkage of the liver with deterioration of its functionality) or, in 30% of cases in adulthood, progression towards cancer of the bile duct.

How is it diagnosed?

Diagnosis before birth is possible if choledochal dilation is significant and visible in prenatal ultrasounds.
The main risk is to confuse it with bile duct atresia (see the section on bile duct atresia) in cystic form, which would require urgent treatment, while a choledochal cyst can be removed later, at around the age of 3-6 months.
After birth, the diagnosis is made through an ultrasound scan and a magnetic resonance cholangiopancreatography (cholangio-MRI) allows for a definition of the exact morphology of the cyst. 

What are the treatments?

Treatment is always through surgery. It should be performed on a non-emergency basis, but rather quickly after the diagnosis, in order to limit the development of liver fibrosis/cirrhosis or cyst complications.

The surgery includes:

• ablation of all major bile ducts (extra –hepatic) that could develop into cancer (including the gall bladder)
• reconstruction of the bile duct by an intestinal loop that is mounted to the liver and sutured to the intrahepatic bile duct

What is the prognosis?

Postoperative results are excellent and there are usually no consequences during recovery.
However, prolonged monitoring with an annual ultrasound scan is required to detect the possible development of a residual millimetric bile duct cancer outside the liver, an extremely rare event.