Fig. 2

a Intraoperative findings suggesting no tumor invasion outside the gallbladder serosa. Arrowheads show the location of the tumor palpated at the peritoneal side of the gallbladder fundus. b Intraoperative ultrasonography showing the dilated cystic duct (CD) joining into the extrahepatic bile duct (EHBD) in the pancreas. c Intraoperative finding just the dissection at just above the confluence of main pancreatic duct and EHBD