The authors present the case of a 64 years woman with a choledochal cyst along with a complex malformation of both intra and extrahepatic bile ducts. The patient was admitted with a diagnosis of acute and underestimated cholecystitis, which was in fact a real acute severe suppurated angiocolitis located at the cystic cavity level along with severe hepato-renal failure. As long as the choledochal cyst evolves as a stand-alone entity, it can frequently be associated with other malformations of the bile ducts--such as choledochal duct stenosis or abnormal connection of the common hepatic duct with pancreatic ducts. The main dilatation was engulfing the whole common bile duct with a fusiform aspect, and the cranial end is opening into a long hepatic duct from which were emerging several biliary segments branches, for both hepatic lobes. This aspect of a multistage convergence with four branches which is opening into a long hepatic bile duct and then in the choledochal cyst, represents an unusual malformation which does not respect the rules described by former published authors.