Internal biliary fistulas may arise from peptic ulceration, operative trauma or, most commonly, as a result of biliary disease with associated calculi. Of the latter group the most frequently seen is the communication between the gallbladder and the upper small bowel through ulceration of a gallstone into the duodenum; this may result in gallstone ileus. Less commonly fistulas develop between the common bile duct and the duodenum from stones in the duct eroding into the bowel or from the penetration of a peptic ulcer into the common duct.
Uncommon too are the fistulas between the biliary tract and the colon. In 1925 Judd and Burden4 reported 26 cholecystocolic fistulas as part of a series of 153 cases of internal biliary fistula seen at the Mayo Clinic. In one of the 26 the diagnosis had been made preoperatively by barium enema. Bernhard1 reported 36 of 109 internal biliary fistulas