Introduction: We present the case of a 78-year-old woman with a history of hypertension and colonic diverticulosis, admitted for diffuse abdominal pain, distension, and constipation lasting five days. Physical examination revealed a distended abdomen with reduced bowel sounds and diffuse tenderness, without signs of peritoneal irritation. Laboratory tests were unremarkable. Abdominal X-ray showed dilated bowel loops. CT scan revealed extensive intrahepatic and choledochal pneumobilia, a contracted gallbladder in continuity with the right colon, and inflammatory changes with diffuse thickening of the sigmoid colon. A transition point was noted at the rectosigmoid junction, where an impacted stone was suspected, without evidence of neoplasia.

Endoscopic Findings and Management: Colonoscopy revealed large diverticula in the sigmoid colon and a round, dark-pigmented lesion occupying nearly the entire lumen, consistent with an impacted biliary stone. Due to its location and size, complete extraction was not feasible initially. Using a Dormia basket, the stone was fragmented and removed. Following the procedure, a significant release of fecal content was observed, and the patient’s intestinal transit normalized, with resolution of the presenting symptoms.

Conclusions : The primary therapeutic goal in biliary ileus is to relieve the intestinal obstruction. Although colonic impaction of ectopic gallstones is uncommon, the presence of luminal narrowing—such as in areas of diverticulosis, as seen in our patient—can favor stone lodging at that level.

Abdominal CT findings of pneumobilia, cholecysto-colonic fistula, and ectopic gallstone provided the definitive diagnostic evidence in this case.

Endoscopic treatment represents a first-line, non-surgical strategy. Therefore, it is essential to be familiar with the specialized instruments—often infrequently used—that are available in our endoscopy units, as they can be crucial in resolving complex scenarios such as the one presented here.