Pancreatic Intraductal Papillary Mucinous Neoplasm Arising Within Heterotopic Pancreas Tissue of the Stomach

Heterotopic pancreas is a pancreatic tissue outside of its normal location. It is usually benign and asymptomatic but rarely can develop neoplasms such as intraductal papillary mucinous neoplasms (IPMNs). A 73-year-old woman undergoing evaluation for chronic reflux was found to have a gastric submucosal lesion on esophagogastroduodenoscopy. Endoscopic ultrasound findings were inconclusive, leading to endoscopic submucosal dissection performed with a complete resection. Histopathology confirmed pancreatic heterotopia with IPMN changes and focal high-grade dysplasia. This case highlights that IPMNs with high-grade dysplasia can rarely arise in gastrointestinal heterotopic pancreas. Careful management and ongoing surveillance are essential due to potential malignant transformation.