Breaking the Size Barrier: Endoscopic Submucosal Dissection of a Massive Flat Gastric Neuroendocrine Tumor

Type I gastric neuroendocrine tumors, arising in chronic atrophic gastritis, are usually small, mucosal, or submucosal elevated lesions. Current guidelines recommend endoscopic resection of lesions ≤20 mm and surgical treatment for those >20 mm. We report an unusual case of a 56-year-old woman with a completely flat (Paris 0-IIb) gastric body neuroendocrine tumor (NET) measuring 140 × 35 mm, detected by virtual chromoendoscopy and successfully resected by endoscopic submucosal dissection without complications. Histology revealed about 40 well-differentiated low-grade NET foci. After 6 months, no recurrence occurred, confirming endoscopic submucosal dissections curative potential in this exceptional giant but flat NET case.