Abstract
A 69-year-old male visited our hospital with a complaint of low abdominal pain. He was diagnosed with acute colon diverticulitis and consequently admitted and treated with antibiotics. He was subjected to screening endoscopy. The endoscopy findings revealed a gastric ulcer, and he was administered a proton pump inhibitor. Moreover, a depressed area was also observed. On follow-up endoscopy after discharge, the depressed area was obvious, and its surface was irregular. Biopsy was performed, and the lesion was diagnosed as a well-differentiated adenocarcinoma. Upon endoscopic ultrasound, the tumor was found to be restricted within the mucous. Accordingly, we speculate that the gastric cancer might have become obvious after the administration of the proton pump inhibitor, as the gastritis was cured and the mucus was clear.
