2025 Volume 67 Issue 12 Pages 2416-2421
A 52-year-old woman underwent EGD due to epigastric discomfort. Multiple elevated lesions, approximately 5 mm in size, were detected from the upper gastric body to the fornix. Among the clustered polyps, a 10 mm polyp with a surface texture that was distinctly different from the others was identified. Magnified narrow-band imaging (NBI) revealed an uneven surface with papillary-to-nodular features. Based on the biopsy findings, which suggested a gastric-type adenoma, the patient underwent endoscopic mucosal resection (EMR). Histopathological analysis of the resected specimen confirmed a gastric-type adenoma with prominent nucleoli. Immunostaining was positive for MUC6 and MUC5AC and negative for MUC2 and CD10, supporting the diagnosis of gastric-type adenoma. However, the distinguishing features between gastric-type adenomas and adenocarcinomas remain unclear. It has been reported that gastric-type adenomas typically exhibit a papillary, granular surface microstructure surrounded by a white zone when observed under magnified NBI. To the best of our knowledge, this is a rare case of gastric-type adenoma arising from sporadic fundic gland polyposis in a patient who was not infected with Helicobacter pylori and had no genetic predisposition
