Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Sep 26, 2021; 9(27): 7973-7985
Published online Sep 26, 2021. doi: 10.12998/wjcc.v9.i27.7973
Gastric neuroendocrine neoplasms: A review
Hüseyin Köseoğlu, Tolga Duzenli, Mesut Sezikli
Hüseyin Köseoğlu, Mesut Sezikli, Department of Gastroenterology, Hitit University, Faculty of Medicine, Çorum 19200, Turkey
Tolga Duzenli, Department of Gastroenterology, Hitit University Erol Olçok Education and Research Hospital, Çorum 19200, Turkey
Author contributions: Köseoğlu H, Düzenli T and Sezikli M contributed equally to this work; Köseoğlu H and Düzenli T designed the research study; Köseoğlu H, Düzenli T and Sezikli M analyzed the recent literature and took part in writing the manuscript; All authors have read and approve the final manuscript.
Conflict-of-interest statement: The authors declare no conflict of interest.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Hüseyin Köseoğlu, MD, Associate Professor, Department of Gastroenterology, Hitit University, Faculty of Medicine, Çorum 19200, Turkey.
Received: February 20, 2021
Peer-review started: February 20, 2021
First decision: May 3, 2021
Revised: May 19, 2021
Accepted: August 18, 2021
Article in press: August 18, 2021
Published online: September 26, 2021

Gastric neuroendocrine neoplasms (g-NENs) or neuroendocrine tumors are generally slow-growing tumors with increasing incidence. They arise from enterochromaffin like cells and are divided into four types according to clinical characteristic features. Type 1 and 2 are gastrin dependent, whereas type 3 and 4 are sporadic. The reason for hypergastrinemia is atrophic gastritis in type 1, and gastrin releasing tumor (gastrinoma) in type 2 g-NEN. The diagnosis of g-NENs needs histopathological investigation taken by upper gastrointestinal endoscopy. g-NENs are positively stained with chomogranin A and synaptophysin. Grading is made with mitotic index and ki-67 proliferation index on histopathological analysis. It is crucial to discriminate between types of g-NENs, because the management, treatment and prognosis differ significantly between subtypes. Treatment options for g-NENs include endoscopic resection, surgical resection with or without antrectomy, medical treatment with somatostatin analogues, netazepide or chemotherapy regimens. Follow-up without excision is another option in appropriate cases. The prognosis of type 1 and 2 g-NENs are good, whereas the prognosis of type 3 and 4 g-NENs are close to the prognosis of gastric adenocancer.

Keywords: Gastric neuroendocrine tumors, Gastric neuroendocrine neoplasm, Gastric neuroendocrine carcinoma, Hypergastrinemia, Carcinoid, Somatostatin receptor imaging

Core Tip: Gastric neuroendocrine neoplasm is an indolent tumor, which is more commonly seen with time. It has 4 subtypes with different clinical characteristics, and diagnostic management and treatment depends on subtypes. This article reviews the history of neuroendocrine tumors, the epidemiology, pathogenesis, clinical aspects and treatment options in patients with gastric neuroendocrine neoplasms.