RESUMO
Choledochal cysts involving the cystic duct are extremely rare, and are usually associated with cystic dilatations of the extrahepatic biliary tract. We describe a patient who presented with jaundice and was found to have a dilatation of the common bile duct on computed tomographic imaging, consistent with a choledochal cyst. He underwent a laparoscopic-converted-to-open cholecystectomy with excision of the choledochal cyst which was found to involve the cystic duct. Choledochal cysts involving the cystic duct are notably missing from the Todani classification. Although exceedingly rare, new cases of these types of cysts are being reported, in part due to advancement of diagnostic imaging modalities. We discuss the current classification scheme for choledochal cysts and we propose an expansion of this scheme.