Early cystic duct carcinoma of new classification

Classically defined cystic duct carcinoma is extremely rare owing to its strict diagnostic criteria, which are not suitable in actual clinical settings. Recently, several new classifications of cystic duct carcinoma were reported, which defined it as a tumor with its center located in the cystic duct. On the other hand, the incidence of cystic duct carcinoma, based on the new classifications, is not rare, but all reported cases are advanced.A 77-year-old man with dilatation of the common bile duct, a stricture at the level of the cystic duct junction, and a filling defect of contrast medium into cystic duct in endoscopic retrograde cholangiopancreatography was diagnosed with cystic duct carcinoma. Radical cholecystectomy with bile duct resection was performed. In the resected specimen, we found that a 2 cm tumor whose center was located in the cystic duct and vertically limited to the mucosal layer. Horizontally, the tumor was superficially spread in the gallbladder, which were also limited to the mucosal layer.Here we report a first case of early cystic duct carcinoma diagnosed according to a new classification that had spread superficially into the gallbladder. When treating an early cystic duct carcinoma, it is important to note that even localized carcinoma can potentially invade into adjacent organs or metastasize to regional lymph nodes due to the location of cystic duct.It is suggested that perform radical resection such as cholecystectomy with gallbladder fossa resection, extrahepatic bile duct resection and regional lymphadenectomy is the treatment of choice.