Choledochal Cyst

A choledochal cyst is congenital cystic or fusiform dilatation of the biliary tree. Abnormal pancreaticobiliary junction with reflux of pancreatic secretions into the bile duct is an important mechanism.

Complications include recurrent cholangitis, pancreatitis, choledocholithiasis, biliary stricture and progressive liver injury. Chronic epithelial inflammation also creates a significant lifetime risk of cholangiocarcinoma, which persists even after cyst excision.

The Todani classification is clinically useful:

• Type I: fusiform or cystic extrahepatic bile duct dilatation
• Type II: true diverticulum of the extrahepatic bile duct
• Type III: intraduodenal choledochocele
• Type IVa: combined intrahepatic and extrahepatic cystic disease
• Type IVb: multiple extrahepatic cysts
• Type V: isolated intrahepatic disease, or Caroli disease.

Children may present with jaundice, abdominal pain or an abdominal mass, although the complete classical triad is uncommon.

Adults more frequently present with complications:

• Recurrent right upper quadrant pain
• Cholangitis
• Acute pancreatitis
• Obstructive jaundice
• Biliary stones

A newly symptomatic choledochal cyst in an adult should be assessed carefully for malignant transformation.

MRCP: preferred investigation for defining the complete intrahepatic and extrahepatic anatomy, distal duct relationship and associated stones or strictures.

Check liver biochemistry and pancreatic enzymes according to presentation.

ERCP is principally therapeutic and is useful for cholangitis, obstructing stones, distal duct pathology or symptomatic choledochocele.

Treat active cholangitis or pancreatitis before definitive elective reconstruction whenever the patient is stable enough to permit staged management.

Type I

Perform complete extrahepatic cyst excision with cholecystectomy followed by Roux en Y hepaticojejunostomy. Internal drainage of the cyst without excision should not be used because retained abnormal biliary epithelium continues to cause stones, cholangitis and malignant risk.

Dissect the distal cyst into the pancreatic head sufficiently to remove abnormal duct while avoiding pancreatic duct injury.

Type II

Excise the diverticulum at its junction with the common bile duct. A small neck can usually be closed primarily. Extensive duct involvement may require biliary reconstruction.

Type III

Symptomatic choledochocele is usually treated endoscopically with endoscopic sphincterotomy with or without cyst deroofing rather than formal extrahepatic bile duct excision.

Type IV

Type IVb is treated similarly to type I with complete extrahepatic cyst excision and biliary reconstruction.

Type IVa requires extrahepatic cyst excision plus management of the intrahepatic disease. Localised severe intrahepatic involvement may require anatomical hepatectomy. Diffuse disease with recurrent cholangitis, biliary cirrhosis or progressive liver failure may require transplantation.

Type V

Localised Caroli disease can undergo segmental or lobar hepatectomy.

Diffuse bilateral disease complicated by recurrent cholangitis, portal hypertension or secondary biliary cirrhosis may require liver transplantation.

Continue long term hepatobiliary surveillance after excision because malignancy can still arise in residual intrahepatic ducts.