Bouveret Syndrome Mimicking Gallbladder Malignancy: A Diagnostic Challenge in an 85-Year-Old Woman.

Bouveret syndrome is a rare complication of cholelithiasis in which a gallstone enters the duodenum via a cholecystoenteric fistula, causing gastric outlet obstruction. Because of chronic inflammation and nonspecific symptoms, the condition can easily be misdiagnosed as a gastrointestinal malignancy. An 85-year-old woman presented with severe weight loss (10 kg), night sweats, and non-bloody vomiting. CT imaging revealed massive aerobilia, a thickened gallbladder wall, and an ill-defined mass at the gastroduodenal junction. These findings raised strong suspicion for a malignant process in the gallbladder or pancreatic head with gastroduodenal infiltration. However, subsequent upper endoscopy revealed the mass to be a huge impacted gallstone obstructing the duodenal bulb. The calculus was successfully fragmented and removed using intracorporeal electrohydraulic lithotripsy, which generates shock waves, resulting in complete resolution of the obstruction without high-risk surgery. Bouveret syndrome can closely mimic the clinical and radiological presentation of gastrointestinal malignancies. Physicians must maintain a high index of suspicion for this syndrome in elderly patients presenting with gastric outlet obstruction with features suggestive of malignancy and aerobilia, as prompt endoscopic evaluation can spare them from unnecessary oncologic interventions.