Gastrinomas are rare neuroendocrine tumours. A 9-year-old boy who initially presented with recurrent upper abdominal pain and was managed as hyperacidity syndrome was later diagnosed to have a primary, retroperitoneal, extra pancreatic gastrinoma after an asymptomatic period of 6 years is presented. At the second presentation, the contrast-enhanced CT revealed an epigastric mass and serum gastrin was grossly elevated. A complete excision of the mass was done; histopathological evaluation showed a well-differentiated neuroendocrine tumour. At a year follow up, the child is asymptomatic and the review imaging and serum gastrin levels are normal.