Endoscopic features of gastric neuroendocrine tumors

The endoscopic features of gastric neuroendocrine tumors (G-NETs) remain unclarified. The present study investigated the endoscopic features of G-NETs in relation to the clinicopathological findings.

This retrospective study analyzed consecutive patients with G-NETs who received endoscopic or surgical treatment between January 2005 and December 2023. The endoscopic and clinicopathological findings of the lesions were analyzed to provide diagnostic information.

Among 29 patients, the characteristic endoscopic findings of G-NETs on white-light images were reddish color (66%), dilated vessels (83%), submucosal tumor-like marginal elevation (59%), and central depression (48%). The gross appearance of G-NETs was classified into two macroscopic subtypes: reddish polypoid lesions (n = 17) and submucosal tumor-like lesions (n = 9). Magnifying narrow-band imaging endoscopy revealed an absent microsurface pattern plus an irregular microvascular pattern in all cases of reddish polypoid lesions with central depressions (100%, 9/9). The findings of a reddish polypoid lesion and an absent microsurface pattern plus an irregular microvascular pattern corresponded to the subepithelial NET component close to the non-neoplastic surface epithelium. Additionally, reddish polypoid lesions were significantly more frequent in type 1 G-NETs than in type 3 G-NETs (80% vs. 11%, p < 0.001), while submucosal tumor-like lesions were significantly more frequent in type 3 G-NETs than in type 1 G-NETs (78% vs. 10%, p < 0.001).

These endoscopic features should increase the index of suspicion and help clinicians to correctly diagnose G-NETs through the pathological examination of biopsy specimens.