A 66-year-old woman presented with abdominal discomfort and iron-deficiency anemia (hemoglobin, 8.3 g/dL). She had been taking 10 mg vonoprazan daily for 3 years for the treatment of gastroesophageal reflux disease. Helicobacter pylori tests (serum anti-IgG antibody and histology) were negative. Abdominal computed tomography revealed polypoid lesions arising from the gastric wall in the duodenal bulb (Picture 1). Esophagogastroduodenoscopy revealed more than 30 pedunculated polyps in the gastric body (Picture 2). At the time of endoscopy, intussusception due to the gastric polyps had likely spontaneously reduced. A biopsy of the polyps revealed fundic gland mucosa with cystic glands, which was consistent with fundic gland polyps, and parietal cell protrusion. We suspected that the gastric polyps were related to proton pump inhibition, and vonoprazan was discontinued. Twelve months later, follow-up endoscopy revealed a marked decrease in the number and size of the polyps (Picture 3). The serum gastrin levels before and after the cessation of vonoprazan were 830 and 130 (pg/mL), respectively. The anemia improved with iron treatment and did not recur. Long-term proton-pump inhibitor use has been reported to induce gastric fundic grand polyp development and bleeding from polyps (1,2). This case demonstrates that vonoprazan, a novel potassium-competitive acid blocker, can also induce the development of gastric fundic gland polyps and anemia.
Picture 1.
Picture 2.
Picture 3.
The authors state that they have no Conflict of Interest (COI).
Acknowledgement
The authors thank Dr. William R. Brown (Denver, Colorado) for assistance in the preparation of the manuscript.
References
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