Pancreatic heterotopia: An overview of a lesion often mimicking neuroendocrine tumour

Pancreatic tissue that has no direct or vascular connection to the main body of the pancreas constitutes ectopic pancreas or heterotopic pancreas (HP). Majority are located in the upper gastrointestinal tract (GIT). HP may be mistaken for neoplasms like neuroendocrine tumour (NET) and adenocarcinoma on endoscopy as well as on histopathology. We report six cases of HP along with review of literature; three of them were misdiagnosed as NET. To the best of our knowledge, this is the first case series of HP from India, rest being case reports. Histopathological features of six cases of HP were analyzed. Variables examined were clinical presentation, age at diagnosis, location, histopathologic type and immunohistochemical profile. Two cases each were seen in duodenum and Meckel’s diverticulum while one case each was seen in stomach and an atretic segment of ileum, a site never reported previously. There were five males and one female with age ranging from one day to 48 years. Patients with gastric and duodenal HP were symptomatic. On histopathology, four cases were intramuscular and two were submucosal. Four cases were of Type I and two cases were of type II. HP should be considered in the differential diagnosis of submucosal upper GI lesions. Awareness, high degree of suspicion and thorough histopathological examination are necessary to arrive at a correct diagnosis. Immunohistochemistry for chromogranin and synaptophysin is useful for confirming the islets especially on small endoscopic biopsies. HP must be considered in the differential diagnosis of submucosal upper GI lesions. Knowledge about this entity, high degree of suspicion and thorough histopathological examination help in arriving at a correct diagnosis and excluding mimics.