A well differentiated, low or intermediate grade tumor with neuroendocrine differentiation that arises from the stomach. The disease is gastric neuroendocrine tumor, well differentiated, low or intermediate grade (MONDO_0015062). Also known as: GNET, gastric NET, gastric NET G1/2, gastric neuroendocrine tumor, gastric neuroendocrine tumour, gastric well differentiated endocrine tumor, gastric well differentiated endocrine tumor/carcinoma, gastric well differentiated endocrine tumour.