Bile duct cysts: Todani classification

I – Cystic (Ia)/saccular (Ib)/fusiform (Ic) dilatation of the extrahepatic bile duct (accounts for 80-90% of cases)

II – Extrahepatic, supraduodenal bile duct diverticulum

III – Intraduodenal diverticulum (choledochocele)

IV – Intra and extrahepatic duct dilatation

IVa – Multiple intra and extrahepatic cysts

IVb – Multiple extrahepatic cysts only

V – Multiple intrahepatic cysts (Caroli’s disease)

References:

Congenital bile duct cysts: Classification, operative procedures, and review of thirty-seven cases including cancer arising from choledochal cyst