choledochal cyst; biliary cyst (includes: choledochocele, Caroli's disease)

Classification

• type I:
  • most common (80-90%)
  • saccular or fusiform dilatation of a portion or entire common bile duct with normal intrahepatic duct
• type II:
  • isolated diverticulum protruding from the common bile duct
• type III: (choledochocele)
  • dilatation of duodenal portion of common bile duct
• type IVa:
  • multiple dilatations of the intrahepatic & extrahepatic biliary tree
• type IVb:
  • multiple dilatations involving only the extrahepatic bile ducts
• type V: (Caroli's disease)
  • cystic dilatation of intrahepatic biliary ducts

Etiology

• cystic dilation of the bile ducts

Epidemiology

• uncomnon
• less uncommon in East Asians

Clinical manifestations

• most present in 1st year of life; adult presentation is rare
• classic triad in a minority of patients
  • intermittent abdominal pain
  • jaundice
  • right upper quadrant abdominal mass

Diagnostic procedures

• endoscopic retrograde cholangiopancreatography (ERCP)
  • dilation of the common bile duct without evidence of obstructing lesion

Radiology

• ultrasonography
• computed tomography
• magnetic resonance imaging

Complications

• cholangitis
• biliary cancer (2%)

Management

• surgical excision with formation of a roux-en-Y anastomosis to the biliary duct

More general terms

• cyst
• biliary disease
• congenital anomaly (birth defect)