Printed from Surgical Pathology Criteria: WHO 2010 has changed back to neuroendocrine cell from endocrine cell for these lesions, Endocrine cell hyperplasia and neoplasia are equivalent terms to those used below, Gastric carcinoids and neuroendocrine cell proliferations arise in three settings, Hyperplasia, dysplasia and neoplasia are not uncommon, Most carcinoids are <1 cm and are not aggressive, May not progress even if not resected, Without MEN1, generally only neuroendocrine cell hyperplasia is seen, With MEN1, may have neuroendocrine cell dysplasia and neoplasia, Such carcinoids may behave aggressively, Over half may invade deeply and metastasize, Types of neuroendocrine cell proliferations, Chromogranin and/or synaptophysin stains are necessary for evaluation of neuroendocrine cells, Scattered individually, primarily in the basal crypt epithelium, Linear or micronodular clusters of at least 5 cells, Micronodular clusters 150 microns in greatest dimension, At least 2 linear chains / mm or 1 micronodule / mm, Enlargement and fusion of five or more micronodules, >150 microns in greatest dimension, Microinfiltration of lamina propria, Nodule with formation of new stroma, Nodules 0.5 mm to 0.5 cm have been termed microcarcinoids, Gastric endocrine cell proliferations typically show features seen in other GI tract well differentiated endocrine proliferations, Occasional reports of scattered larger atypical nuclei, Trabecular, acinar, pseudo glandular architecture, Variable positivity for neuroendocrine markers, It has been proposed that type A and B hyperplasia and dysplasia may progress to carcinoid (Berna 2008, Annibale 2001), This is not universally accepted for hyperplastic lesions (Solicia 1995), It would appear that both merit followup, The behavior of carcinoids is dependent upon size, proliferation rate and the setting in which it arises (see, Well differentiated processes including carcinoids, Duodenum NOS and proximal jejunum, Ileum and distal jejunum Berna MJ, Annibale B, Marignani M, et al. Current concepts on gastric carcinoid tumors. You may be trying to access this site from a secured browser on the server. 4. Endoscopic view of antral tumor (A) showing irregular pattern on NBI (B). This .