Gastric neuroendocrine tumour occurring secondarily to a duodenal gastrinoma in a patient with multiple endocrine neoplasia type 1: a case example of type 2 gastric neuroendocrine tumours

Abstract

Introduction Neuroendocrine tumours (NETs) of the stomach comprise 6% of all gastrointestinal NETs. They can be divided into four subtypes based on the clinical setting in which they arise. Type 1 and 2 NETs arise on a background of hypergastrinaemia and are derived from enterochromaffin-like (ECL) cells. Type 3 and 4 arise in patients with normal serum gastrin levels. Case report A 68-year-old man with multiple endocrine neoplasia type 1 (MEN-1) underwent an endoscopy for altered bowel habit. Biopsies of a gastric ‘polyp’ were taken along with a ‘lump’ seen in Dl. On microscopy the gastric ‘polyp’ showed a 0.8 mm well-differentiated NET within the lamina propria comprised of epithelioid cells with central round nuclei and vesicular chromatin, arranged in small trabeculae and acini. The tumour showed immunoreactivity with synaptophysin and chromogranin-A. The duodenal lump was also a 2.5 mm well-differentiated NET, comprised of nests of bland epithelioid cells with granular cytoplasm, extending from the lamina propria into muscularis mucosae. Along with synaptophysin and chromogranin-A it was also positive for gastrin, indicative of a functional gastrinoma. Discussion This rare case is reported to illustrate the pathophysiology of the occurrence of type 2 gastric NETs arising in the setting of MEN-1.