The patient presented to the emergency department complaining of dull diffuse abdominal pain, distension and vomiting which raised clinical suspicion for bowel obstruction. By clinical examination, abdominal distension and a left inguinal hernia were detected. 

CT abdomen showed mechanical obstruction with the transitional zone at the distal jejunal bowel loops causing partial intestinal obstruction, the causative mechanical element is a large oval intra-luminal hyperdense stone measuring 7 cm. Also noted, normal mural enhancement of all bowel loops, no pneumoperitoneum, a left inguinal hernia containing portions of the sigmoid colon. Also evident was a tiny fistula tract connecting the gallbladder neck with the 1^st part duodenum representing a cholecystoduodenal fistula.

All the CT signs suggest gallstone ileus causing mechanical obstruction. The stone reached the bowel lumen through the cholecystoduodenal fistula.

The patient entered the operating room 24 hours after the CT study; the operative data confirmed the radiological diagnosis of gallstone ileus. The surgeon removed the stone and performed a gastrojejunostomy.