Gastric Adenocarcinoma Arising from Heterotopic Pancreas Presenting as Gastric Outlet Obstruction 10 Years after the First Diagnosis

Gastric heterotopic pancreas is a relatively uncommon incidental finding. On the other hand, the presentation of gastric adenocarcinoma arising from a heterotopic pancreas is rare. This paper reports a case of gastric adenocarcinoma arising from a heterotopic pancreas that presented as a gastric outlet obstruction 10 years after the initial diagnosis of a suspicious submucosal tumor. Endoscopy revealed a pyloric stricture with prepyloric wall thickening and a complete gastric outlet obstruction. Abdominal and pelvic computed tomography exposed a severely distended gastric lumen at the antrum with heterogeneously enhancing circumferential wall thickening in the prepyloric antrum and pylorus. Because conservative treatment was ineffective and a malignancy could not be excluded, laparoscopic subtotal gastrectomy with a gastrojejunostomy was performed for histological confirmation and treatment. The histopathology diagnosis was advanced gastric carcinoma arising from heterotopic pancreatic tissue.