Abstract

Context Gastric pancreatic heterotopia is a relatively common incidental finding; however, malignancy arising in this tissue is an extremely rare occurrence, with nonspecific clinical, radiographic, and intraoperative features. We herein report the case of adenocarcinoma arising in ectopic pancreatic tissue of the gastric antrum and review the literature to summarize all recent cases of malignancy arising in gastric pancreatic heterotopia. Case report A Forty-five-year-old male presented with six-week history of gastric outlet obstruction found on endoscopy to be secondary to a submucosal mass within the gastric antrum. Pre-operative suspicion of a gastric cancer vs. gastrointestinal stromal tumor prompted a subtotal gastrectomy. Recognition of perineural invasion associated with a well-differentiated adenocarcinoma prompted further histological sections to be taken, and a gastric pancreatic heterotopia was identified associated with the malignancy through a transition zone. The diagnosis of malignancy arising in pancreatic heterotopia was made. Conclusions Accurate diagnosis of this rare diagnosis remains a challenge and is heavily reliant on histopathological evaluation. The presence of perineural invasion in a gastric adenocarcinoma should prompt suspicion of a nonprimary gastric cancer such as a gastric pancreatic heterotopia.