Gastric Epithelial Neoplasms with Fundic Gland Mucosa Lineage - Size and Morphology Correlate Well with Tumor Depth.

Aim Gastric adenocarcinoma of the fundic gland type (GA-FG) without submucosal invasion is classified as an oxyntic gland adenoma (OGA). This study aimed to investigate differences in characteristics between OGAs and GA-FGs with submucosal invasion. Methods A retrospective analysis of 15 OGAs and 14 GA-FGs diagnosed between April 2016 and March 2025 was conducted. Patient clinical characteristics as well as tumor size, location, and endoscopic features (shape, surface redness, dilated vessels on surface) were compared between the two groups. Results There were no significant differences regarding patient sex, age, or Helicobacter pylori infection status. OGAs were significantly smaller than GA-FGs. Additionally, flat type and the absence of dilated vessels were identified as characteristic endoscopic features of OGAs. Location and surface redness did not differ between these two types. Conclusions Among gastric fundic gland type tumors, OGAs are characterized by small size, flat morphology, and the absence of dilated vessels.