[A cholecysto-enteric fistula with a gallstone ileus diagnosed by CT]

Gallstone ileus is an uncommon but severe complication of cholecystitis, which can only occur following perforation of the gallbladder and formation of a cholecystoenteric fistula. The diagnosis can be established by means of abdominal plain film when the classic triad described by Rigler (small-bowel obstruction, ectopic gallstone and pneumobilia) is observed. A patient with abdominal obstruction and equivocal findings on plain film X-ray and abdominal sonography is presented, in whom the gallstone ileus was reliably diagnosed by CT.