[Acute obstruction of the colon secondary to biliary lithiasis].

Gallstone ileus is an unusual cause of mechanical obstruction of the gastrointestinal tract; but obstruction of the colon by a gallstone is an even more rare event, and there are few references in the literature. We describe the cases of two elderly women who were admitted to the Emergency Service with a mechanical obstruction of the colon and air in the biliary tract. A barium-enema examination showed the presence of a foreign body in the sigmoid colon; this was found to be a gallstone in a subsequent colonoscopy in one of the patients; a precise preoperative diagnosis was not possible in the other. In both cases the obstruction was caused by a gallstone impacted in the sigmoid colon and a cholecystocolonic fistula was evident in a postoperative barium enema examination. Correction of the obstruction is the main objective of initial treatment. The repair of the fistula can be performed at the same time or at a later date.