LAUSR

Abstract Rationale: Phlegmonous gastritis is a rare bacterial infection of the gastric wall with high mortality. However, diagnosis of phlegmonous gastritis is difficult and standard treatment remains unestablished. Patient concerns: We report a 33-year-old male patient with mixed-phenotype acute leukemia who developed acute phlegmonous gastritis during the neutropenia phase on induction chemotherapy and was successfully treated. Diagnoses: The patient was diagnosed with phlegmonous gastritis, which might be caused by Stenotrophomonas maltophilia on the basis of clinical manifestation, physical examination, enhanced computed tomography scan, histological finding, and microorganism culture of biopsied specimen in endoscopy. Interventions: The patient was treated with gastrointestinal decompression and broad-spectrum antibiotics. Outcomes: He recovered from phlegmonous gastritis and received the 2nd cycle of chemotherapy with no complaint of abdominal discomfort. Lessons: Early recognition and proper management including broad-spectrum antibiotics are key approaches to phlegmonous gastritis.