Figure 2. a. A peri-ampullary adenocarcinoma (arrows) involves the duodenal wall and ampulla and extends in a polypous-exophytic fashion (arrow heads) into the distal end of the dilated common bile duct. b. The biliary adenoma presents macroscopically as a well-circumscribed exophytic polypous lesion (arrows) in the extrapancreatic portion of the dilated common bile duct (arrow heads).