Gastroduodenal Intussusception With Gastric Outlet Obstruction and Periampullary Compression Due to a Gastrointestinal Stromal Tumor in the Stomach.

BACKGROUND Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. Their presentation varies from bleeding to perforation, but they rarely manifest as gastroduodenal intussusception or obstructive jaundice. We report a rare case of a gastric GIST that caused intussusception leading to gastric outlet obstruction with biliary obstruction and acute pancreatitis. CASE REPORT A 71-year-old woman presented with melena, vomiting, and generalized weakness. Evaluation revealed severe anemia and elevated liver and pancreatic enzymes. Imaging and endoscopy identified a large polypoid mass in the gastric antrum prolapsing into the duodenum. Magnetic resonance cholangiopancreatography showed a dilated common bile duct but no choledocholithiasis. She was advised to undergo surgery, during which a gastroduodenal intussusception compressing the ampulla was identified. The mass was excised via gastrotomy with wide margins. Postoperative recovery was uneventful. Histopathology confirmed a low-grade (G1) gastric GIST (pT3, CD117/Discovered On GIST-1 [DOG1]-positive, Ki-67 ~3%) with clear margins. CONCLUSIONS Gastroduodenal intussusception is a rare condition in adults. Fewer than 50 cases have been reported, and more than half were attributed to GISTs. Obstructive jaundice or pancreatitis due to external ampullary compression is uncommon. Imaging modalities such as computed tomography and magnetic resonance imaging are essential for diagnosis. Surgical excision remains the mainstay of management. This case highlights a rare, complex presentation of gastroduodenal intussusception with biliary obstruction due to a gastric GIST.