Choledochal cysts are rare cystic dilatations of the bile ducts, which are commonly found in children. Choledochal cysts in adults are uncommon, and cystic dilatation of the cystic duct (type VI choledochal cyst) is a unique occurrence. To date, specific pathogenic and diagnostic criteria for describing type VI cysts have been lacking. This report attempts to lay down the specific diagnostic and management criteria of this uncommon entity, with reviews of all available cases reported in the literature.