A case of gastric neuroendocrine tumor with an unusual morphology

Gastric neuroendocrine tumors (NETs), derived from enterochromaffin-like cells, commonly exhibit submucosal extension and manifest as submucosal tumor (SMT)-like lesions during endoscopy. We report a rare case of a gastric NET with endoscopical unusual pedunculated and reddish morphology. A 15-mm lesion in the gastric body showed histologically proved to be a grade G2 NET. Endoscopic submucosal dissection was performed, followed by surgery due to lymphatic invasion. Histological examination of the background gastric mucosa in the resected specimen revealed features of autoimmune gastritis, consistent with a type 1 gastric NET according to the Rindi classification. Recognition of such atypical morphology may aid diagnosis.