Choledochal cyst

Rare congenital condition

• Usually develops in infancy/childhood
• Often associated with Anomalous Pancreatobiliary duct junction (APBDJ) in 80-90%
  • Defined as pancreatic duct joining CBD >15mm proximal to ampulla
  • Results in long common channel
  • Results in free reflux of pancreatic secretions into the biliary tract, increased biliary pressures, inflammatory changes in biliary epithelium
  • This may be related to formation of choledochal cysts
• Incidence around 1 in 100,000 (much higher in Asian countries)
• 4:1 more common in women

Complications

• Increased risk cholangitis
• Increased risk malignant degeneration
  • Higher than general population, but still low

Classification

Todani classification

• • Type I most common - 80-90% - dilation of extrahepatic biliary tree
    • IA - cystic
    • IB - focal
    • IC - fusiform
    • 10% risk of cancer, usually by age 40
  • Type II - saccular diverticulum of extrahepatic CBD
    • Not associated with APBDJ, low risk of malignant transformation
    • Often don't need to intervene
  • III - CBD dilatation within duodenal wall - choledochocoele
    • Rarely need to intervene
  • Type IV - cystic dilation of both intra and extrahepatic biliary tract also common 15-20% - multiple cysts
    • Hardest to deal with
    • IVA - both intra- and extra-hepatic
    • IVB - extra-hepatic only
  • V - intrahepatic cysts - Caroli's disease
    • Can be either part or all of the liver involved

Presentation

• Differentiate from just a capacious duct
  • Younger patient - probably cyst
  • Smooth taper - probably cyst
  • ABPDU - probably cyst
• Classical triad - RUQ pain, jaundice, palpable mass - but this is <10% of presentations
• Children commonly have an abdominal mass and jaundice
• 80% are resected by age 18, so less commonly seen in adults
• Adults -
  • Pain 87%
  • Jaundice 42%
  • Nausea 29%
  • Cholangitis 26%
  • Pancreatitis 23%
  • Palpable mass 13%
• Frequently associated with symptomatic gallstones/cholecystitis
• Caroli's syndrome
  • Type V choledochal cysts throughout whole intra-hepatic biliary tree, associated with portal hypertension and congenital cirrhosis
  • If sepsis develops - stone removal wherever feasible

Diagnosis

• Imaging - USS or CT
• ERCP/MRCP/PTC is required for operative planning, obviously MRCP is easiest
  • Need to look for APBDJ, consider cholangiocarcinoma
• Biopsy (brushings/FNA) doesn't help

Management

• Traditionally was cystenterostomy (internal drainage procedures) and cholecystectomy
  • Persistent biliary stasis, cholangitis, pancreatitis, recurrent strictures, liver fibrosis, and persisting risk of cholangiocarcinoma
• Mostly now cholecystectomy and complete resection of cyst with biliary-enteric anastomosis
• Type I: cholecystectomy then Kocher's maneuvre. Dissect out anterior wall, then ligate CBD below. Then take off portal vein and mobilise to level of hepatic duct bifurcation and divide just distal to bifurcation. Need to do frozen section here. Reconstruction with roux-en-Y hepaticojejunostomy.
• Type II: simple diverticulectomy and closure of CBD at cyst neck
• Type III: mostly small which can be managed with endoscopic sphincterotomy. Larger cysts may need transduodenal excision.
• Type IV: Challenging. Complete excision is not always possible. Excise the external components and reconstruct similar to type I cysts. Partial hepatectomy is recommended for any intrahepatic component likely to result in future complications.
• Type V: Treat symptoms first. Surveillance for cholangiocarcinoma with serial imaging and serum CA19-9.
  • Hepatic resection may be used for symptoms confined to one lobe of liver.
  • Complicated bilobar disease and recurrent cholangitis despite maximal medical therapy, portal hypertension, or suspicion of early cholangiocarcinoma requires liver transplant.

Prognosis

• Five-year survival in operative patients exceeds 90%
• Need to continue long-term cholangiocarcinoma surveillance?
  • Do need to keep them in clinic, but more to see complications of hep-jej