Hemorrhagic polyps formed like fundic gland polyps during long-term proton pump inhibitor administration

We report a rare case of hemorrhagic gastric polyps resulting in anemia during long-term proton pump inhibitor (PPI) administration that endoscopically looked like a fundic gland polyp (FGP). A 44-year-old man presented complaining of anemia and tarry stools. Esophagogastroduodenoscopy (EGD) demonstrated multiple white edematous polyps in the corpus and antrum, which were considered to be FGPs. We attempted endoscopic hemostasis but hemorrhaging increased because of hemorrhagic polyps and vulnerable gastric mucosa. Re-bleeding occurred several times. Polyp resection was performed at 24 polyp sites. We also ceased the administration of PPI. Microscopically, polyps showed characteristics of hyperplasia in the foveolar epithelium, extensions of fundic glands, and edema of the stroma. The proliferation of parietal and chief cells was also observed. Immunohistochemically, aquaporin-4 (AQP4) and KCNQ1-positive parietal cells and dilated mucous glands were found from the basal side to the apical side of the mucosa. These findings were compatible with the development of lesions associated with the long-term administration of PPI. EGD revealed an improvement in the vulnerability of gastric mucosa and the development of polyps, with no further gastric polyps observed 1 year after discharge. Bleeding from polyps resembling FGPs is generally rare, with indications that long-term PPI administration may induce such bleeding.