Recognizing Gastric Oxyntic Gland Neoplasms: Characteristic Endoscopic Appearance for Improved Detection

Background: Gastric oxyntic gland neoplasms (GOGNs)—including oxyntic gland adenoma (OGA), gastric adenocarcinoma of fundic gland type (GA-FG), and gastric adenocarcinoma of fundic gland mucosa type (GA-FGM)—are rare epithelial neoplasms that often lack overt malignant appearance on endoscopy. This study aimed to characterize the endoscopic features of GOGNs that may facilitate their recognition. Methods: We retrospectively analyzed consecutive, histologically confirmed GOGNs diagnosed at a tertiary center between January 2019 and July 2025. Endoscopic features on white-light endoscopy (WLE), magnifying narrow-band imaging (NBI), and endoscopic ultrasonography (EUS) were evaluated. Results: Among 156,240 upper endoscopic examinations, 35 patients were diagnosed with GOGNs (0.028%). Lesions were mostly small (median 6 mm) and located in the fundus/upper body (52%), predominantly Paris type 0-Ⅱa (57%) or subepithelial-like elevations (60%). Color was similar to the surrounding mucosa (49%) or mildly reddish (37%), occasionally showing branching vessels (31%) or focal pigmentation (14%). On NBI, OGA and GA-FG lesions (n = 12) frequently showed regularly enlarged crypt openings (92%) and branching vessels (83%) with ill-defined margins (75%), whereas GA-FGM (n = 4) more often showed a distinct demarcation line (75%) with irregular microvascular/microsurface patterns (50%). EUS demonstrated localization mainly within the middle-to-deep mucosal layer and occasional submucosal extension, with intact muscularis propria. Conclusions: GOGNs typically present as small, inconspicuous elevated lesions in the fundus or upper stomach, often with near-normal or slightly reddish mucosal color and characteristic surface vascular and magnifying features. Awareness of these endoscopic patterns may improve recognition of GOGNs during routine endoscopy. Larger studies are needed to validate these findings.