Endoscopic diagnosis and management of type I neuroendocrine tumors.

Type I gastric neuroendocrine tumors (TI-GNETs) are related to chronic atrophic gastritis with hypergastrinemia and enterochromaffin-like cell hyperplasia. The incidence of TI-GNETs has significantly increased, with the great majority being TI-GNETs. TI-GNETs present as small (< 10 mm) and multiple lesions endoscopically and are generally limited to the mucosa or submucosa. Narrow band imaging and high resolution magnification endoscopy may be helpful for the endoscopic diagnosis of TI-GNETs. TI-GNETs are usually histologically classified by World Health Organization criteria as G1 tumors. Therefore, TI-GNETs tend to display nearly benign behavior with a low risk of progression or metastasis. Several treatment options are currently available for these tumors, including surgical resection, endoscopic resection, and endoscopic surveillance. However, debate persists about the best management technique for TI-GNETs.