Choledochal cysts are classified into five main types based on the Todani classification:
Type I: Cystic dilatation of the common bile duct Type II: Diverticulum of the bile duct Type III: Choledochocele, dilatation of the distal common bile duct Type IV: Multiple cysts in the intrahepatic and extrahepatic bile ducts Type V: Caroli disease, cystic dilatation of the intrahepatic bile ducts