Gastric Outlet Obstruction Secondary to Cholecystoduodenal Fistula With Gallstone-Induced Extrinsic Duodenal Compression

ABSTRACT Gastric outlet obstruction (GOO) caused by gallstone disease is rare and typically results from the Bouveret syndrome, with intraluminal gallstone impaction following cholecystoenteric fistula formation. We report a 69-year-old woman with GOO caused by extrinsic duodenal compression from a gallstone retained within a contracted gallbladder adjacent to a cholecystoduodenal fistula, without intraluminal migration or biliary obstruction. Computed tomography, magnetic resonance cholangiopancreatography, endoscopy, and endoscopic ultrasound (EUS) established the diagnosis, with EUS guiding fistula dilation, drainage, and stent placement. Symptoms improved without definitive stone extraction, although malnutrition persisted. This case represents an atypical intermediate phenotype between the Bouveret and Mirizzi syndromes and highlights the therapeutic value of EUS.