Case Report: A giant gallstone causing cholecystoduodenal fistula with Bouveret syndrome and acute pancreatitis

Introduction and importanceBouveret syndrome is a rare form of gallstone ileus characterized by gastric outlet obstruction secondary to impaction of a gallstone that has migrated into the gastrointestinal tract through a cholecystoduodenal fistula. It predominantly occurs in elderly patients with multiple comorbidities. Cases involving giant gallstones complicated by acute pancreatitis are exceedingly uncommon and pose significant therapeutic challenges.Case presentationA 72-year-old woman was admitted with a 6-day history of persistent right upper quadrant abdominal pain and distension, accompanied by nausea, vomiting, and constipation. Her medical history was notable for diabetes mellitus, hypertension, prior cerebral infarction, and chronic renal insufficiency.Clinical findings and investigationsPhysical examination revealed marked tenderness in the right upper quadrant with a positive Murphy’s sign. Laboratory evaluation demonstrated leukocytosis and markedly elevated serum amylase levels, consistent with acute pancreatitis. Abdominal computed tomography (CT) showed cholelithiasis, cholecystitis, pneumobilia, and findings suggestive of a cholecystoduodenal fistula. Endoscopy revealed a giant gallstone measuring approximately 3.5 × 6.0 cm impacted in the descending portion of the duodenum, resulting in complete obstruction.Intervention and outcomesUnder general anesthesia, the stone was successfully fragmented and removed in a single endoscopy session using electrohydraulic lithotripsy combined with a retrieval basket and snare under C-arm fluoroscopic guidance. The procedure was completed under a single session of general anesthesia, restoring duodenal patency. Postoperatively, the patient received broad-spectrum intravenous antibiotics and supportive therapy, with significant symptom relief. She recovered uneventfully and was discharged on postoperative day 6, with no recurrence observed during three-month follow-up.Relevance and impactThis case highlights that, in elderly high-risk patients, endoscopic lithotripsy and stone extraction may serve as a safe, effective, and minimally invasive first-line treatment option for Bouveret syndrome caused by giant gallstones, particularly when complicated by acute pancreatitis, offering valuable clinical insight.