Gallbladder & extrahepatic bile ducts

Extrahepatic bile duct nonneoplastic and tumors

Choledochal cyst

Last author update: 1 September 2012
Last staff update: 14 September 2021

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PubMed Search: Choledochal cyst[TIAB] "extrahepatic bile ducts"

Hanni Gulwani, M.B.B.S.
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Cite this page: Gulwani H. Choledochal cyst. website. Accessed September 30th, 2023.
Definition / general
  • Associated with other hepatobiliary tract abnormalities
  • May rupture spontaneously, be associated with reflux of pancreatic enzymes into bile duct
  • Associated with stones in 1 - 30% of cases
  • Not actually a cyst but a dilation of common bile duct which may secondarily obstruct other biliary ducts or the duodenum
  • 2 - 8% develop biliary tract carcinoma (20x normal risk) at mean age 34 years, lower risk if surgery earlier in life (age 10 years or less), carcinoma may develop within wall of cyst, within gallbladder or bile ducts
  • In Korea, usually type I or IVa (Arch Surg 2011;146:1178)

  • Type 1: segmental or diffuse fusiform dilation of common bile duct (50 - 90%)
  • Type 2: diverticulum of common bile duct
  • Type 3: dilation of intraduodenal common bile duct (choledochocele)
  • Type 4: multiple cysts of extrahepatic bile ducts with (4A) or without (4B) cysts of intrahepatic ducts
  • Type 5: one or more cysts of intrahepatic ducts (Caroli disease)
  • 1 per 13,000 live births in U.S. vs. 1 per 1,000 in Japan
  • 75% girls
  • Most common cause of obstructive jaundice in infants beyond infancy but may be found at any age
Case reports
  • Complete cyst removal with biliary reconstruction, usually with Roux-en-Y hepaticojejunostomy
Gross description
  • Contain 1 - 2 liters of bile, up to 15 cm in diameter
  • Wall is fibrous, variable calcification, 2 - 10 mm thick
Microscopic (histologic) description
  • Focal columnar epithelium (more intact in infants)
  • Walls composed of dense fibrous tissue, scattered smooth muscle and elastic fibers
  • Variable chronic inflammatory infiltrate (increases with age)
  • Variable hyperplasia, metaplasia, dysplasia
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