Abstract
Introduction: Gastric neuroendocrine tumors (gNETs) are cancers that arise from the enterochromaffin-like cells (ECL cells) of the stomach mucosa. They are considered rare cancers with a benign course and neuroendocrine differentiation. Though they are not common, the diagnosis is becoming higher, because of the high usage of endoscopy and the technical enhancement of endoscopies and physicians. The ECL cells bind to silver salts avidly and have a major role in the regulation and maintenance of the acid secretion. After eating, the G cells of the antrum produce gastrin and secret it which will stimulate the ECL cells and the histamine-producing parietal cells to produce hydrochloric acid (HCL). The negative feed-back is very important, it comes from the D cells, which are stimulated by the HCL and produce somatostatin which will reduce the secretion of gastrin. It is critical to understand the mechanisms in order to categorize and classify gastric gNETs in 4 clinical types, with distinct proper management plan and prognosis. It is also essential to emphasize that this classification system is different from the three histological grades recommended by the World Health Organization (WHO). Moreover, the WHO terminology for gNETs underwent changes in recent years, which amplified the difficulty to understand this complex disease.
Aim of work: In this review, we will discuss neuroendocrine tumors. Methodology: We did a systematic search for Neuroendocrine tumors using PubMed search engine (http://www.ncbi.nlm.nih.gov/) and Google Scholar search engine (https://scholar.google.com). All relevant studies were retrieved and discussed. We only included full articles. Conclusions: Gastric neuroendocrine tumors (gNETs) are cancers that arise from the enterochromaffin-like cells (ECL cells) of the stomach mucosa. They are considered rare cancers with a benign course and neuroendocrine differentiation. Though they are not common, the diagnosis is becoming higher, because of the high usage of endoscopy and the technical enhancement of endoscopies and physicians. Gastric NETs consist of a complex disease that includes different subtypes with distinct management and prognosis. The management of gNETs is based on the clinical type, disease extent, the differentiation of the lesion and the presence or absence of poor prognostic factors. According to the WHO, these cancers are categorized into 3 histologic degrees with distinct prognosis Correct identification of the clinical type and histological grade allows for a tailored management. Further studies will clarify the diseases biology and improve its treatment.