Obstructive and inflammatory gastric heterotopic pancreatic tissue

Heterotopic pancreas is defined as pancreatic tissue arising ectopically with no vascular or anatomic contiguity with the pancreas proper and is believed to arise embryologically during rotation of the foregut and fusion of the dorsal and ventral pancreatic buds. We report a case of gastric heterotopic pancreas presenting as an obstructive inflammatory mass with the clinical differential diagnosis of gastric carcinoma. A 54 year-old woman presented with a history of four days of severe, acute-onset abdominal pain. Abdominal ultrasound showed a gastric antral mass. This was confirmed on computerized tomography, which revealed a hypo-dense mass with heterogeneous enhancement in the gastric antrum and multiple ill-defined hypo-dense areas in the liver suspicious for metastases. A preoperative diagnosis of malignant neoplasm was strongly favored, and a subtotal gastrectomy was performed. Microscopic examination of the specimen revealed submucosal and deeply seated intra-muscular and mural heterotopic pancreatic tissue, comprised of both ductal and acinar structures, surrounded by exuberant acute and chronic inflammation. The ducts were inflamed and showed marked cytologic atypia, favored to be of reactive nature. There was overlying mucosal ulceration with marked acute and chronic full-thickness gastric mural inflammatory response with abscess formation. This is the second reported case of obstructive gastric heterotopic pancreas, presenting as an inflammatory mural gastric mass.