A 20-year-old woman was admitted to our hospital for consolidation therapy for acute leukemia. Seventeen days after her treatment, she developed abdominal pain, vomiting, and hematemesis. Laboratory data showed a decrease in neutrophils and a high inflammatory response. Contrast-enhanced computed tomography (CT) showed diffuse edematous thickening of the gastric wall and a small amount of ascites. Esophagogastroduodenoscopy showed hemorrhagic inflammatory findings with prominent white moss adherence from the gastric body to the fornix. No mucosal changes in the gastric antrum were noted. We suspected that an opportunistic infection developed in this immunosuppressed patient. Under fasting control, meropenem, micafungin, proton pump inhibitors, and vancomycin, were administered. Her abdominal symptoms improved on the sixth day after treatment, and the thickening of the gastric wall was noted on the CT scan. Bacteriological examination of the gastric mucosa showed Bacillus cereus, and the diagnosis of infectious gastritis due to myelosuppression was made.
