Choledochal cyst of the proximal cystic duct: a taxonomical and therapeutic conundrum.

Isolated choledochal cysts involving the cystic duct are rare. We present a case of a choledochal cyst involving only the proximal cystic duct, and discuss the taxonomic and therapeutic challenges. There is a need for a clearly defined classification system for these cysts as they may be categorised as either type II or type VI cysts. The optimal treatment remains debatable, with some authors recommending a bilioenteric reconstruction owing to the wide cystic duct-bile duct junction. However, we suggest that a cholecystectomy should be performed with examination of the specimen and frozen section in case of any abnormality rather than upfront bile duct excision. In addition, given the rarity of this condition and the paucity of long-term data, we recommend meticulous follow-up for development of any malignancy.