Multiple Gastric Neuroendocrine Tumors Associated with Long-term Use of a Proton Pump Inhibitor and a Potassium-competitive Acid Blocker.

A 52-year-old man who had been using a proton pump inhibitor (PPI) and a potassium-competitive acid blocker (P-CAB) for 14 years underwent esophagogastroduodenoscopy and was found to have three neuroendocrine tumors (NETs) in the gastric body. Following detailed examinations, parietal cell dysfunction was excluded, and the NETs did not meet the criteria for the Rindi classification types I-III. The lesions were ultimately considered to be associated with the long-term use of the PPI and P-CAB. We performed endoscopic submucosal dissection of the lesions, with no recurrence or new lesions noted after discontinuation of the PPI and P-CAB.