Wada Y, Kushima R, Kodama M, et al. - Mainly in chronic gastritis caused by Helicobacter pylori (H. pylori) infection, occurrence of pyloric-type glands in the gastric oxyntic mucosa is observed which results from metaplastic changes including pyloric metaplasia (PM) and pseudopyloric metaplasia (PPM). Researchers here used 314 biopsy specimens of gastric greater curvature of the middle body before H. pylori eradication (HPE) to perform classification of the histological changes in gastric mucosa according to the Updated Sydney System focusing on PM and PPM. Then, they counted the numbers of PM and PPM glands in 47 specimens, and followed up individuals over 10 years after HPE. Identification of PPM was done jointly with inflammation, activity, atrophy, and intestinal metaplasia, but PM was identified more frequently than PPM as atrophy and intestinal metaplasia progressed. Significant regression was observed of both PM and PPM within 6 years after HPE. Based on these findings, PM and PPM are identified as distinct modulations of the same line of differentiation, which are both reversible, with PM potentially emerging from PPM upon progression.