Heterotopic pancreas is a silent gastrointestinal malformation that may become clinically evident when complicated by inflammation and pseudocyst formation. We report a 26 year-old male presenting with vomiting, pain and abdominal distention. An abdominal CT scan showed an important gastric distention secondary to a 4-cm cystic lesion located in the antrum wall. An endosonography showed that the lesion obstructed the gastric outlet and was compatible with a pseudocyst. A cysto-gastrostomy was performed draining the cyst. Its high lipase and amylase content confirmed that it was a pancreatic pseudocyst. Six months later, the lesion appeared again and a subtotal gastrectomy was performed Histopathology confirmed ectopic pancreatic tissue.