Another type of choledochal cyst beyond the Todani classification

The classification of choledochal cyst has changed from 3 types described by Alonso-Lej to 5 types described by Todani, but these classifications do not include dilatation of the cystic duct. The sixth type of choledochal cyst has been described by some authors for the cystic dilatation of the cystic duct. It is so rare that accurate diagnosis is difficult before operation. We present a 15-month-old girl with a type VI choledochal cyst that was misidentified preoperatively as a type I choledochal cyst. Besides the gall bladder and the cystic duct cyst, we also excised the distal part of the common bile duct and performed reconstruction with Roux-en-Y hepaticojejunostomy. From a review of the literature, we have determined that there is a more direct route to adequate diagnosis and management of the sixth type of choledochal cyst.