A well differentiated, low grade neuroendocrine tumor (carcinoid tumor) that arises from the stomach. The vast majority of cases arise from the corpus-fundus region. The mitotic count is less than 2 per 10 HPF and/or the Ki67 index is equal to or less than 2 percent. It may be associated with autoimmune chronic atrophic gastritis, multiple endocrine neoplasia type 1, or it may be sporadic. The disease is Monarch Disease Ontology id MONDO_0006227 (gastric neuroendocrine tumor G1). Also known as: gastric ECL cell NET, gastric ECL cell NET G1, gastric ECL cell, histamine-producing NET, gastric ECL-cell carcinoid tumor, gastric ECL-cell carcinoid tumour, gastric NET G1, gastric carcinoid tumor, gastric carcinoid tumour.