INTRODUCTION: Diffuse B-Cell Lymphoma (DBCL) is an aggressive, high-grade cancer that arises from neoplastic proliferation of B cells. Primary gastrointestinal (GI) lymphoma is the most common type of extranodal lymphoma and occurs in 30-40% cases. This case report is unique in that it highlights a patient who presented with GI bleeding due to metastatic DBCL. CASE DESCRIPTION/METHODS: A 64 yearold male with a history of coronary artery disease (CAD) status and atrial fibrillation on apixaban, clopidogrel, and aspirin presented to the emergency room with a one day history of hematemesis and melena. He denied a loss of consciousness, fall, chest pain, headache, fevers, or recent weight loss. Patient had no endoscopic history. The patient was tachycardic, hypotensive, and tachypneic on presentation. Physical exam was notable for diffuse lymphadenopathy. Lab findings included an initial hemoglobin of 9.4 g/dL, a blood urea nitrogen (BUN) of 62 mg/dL, and creatinine of 1.51 mg/ dL. Computed tomography (CT) abdomen and pelvis showed extensive lymphadenopathy, multiple small splenic lesions, and pulmonary nodules concerning for lymphoma (Figure 1). Esophagogastroduodenoscopy (EGD) showed a medium-sized ulcerated bleeding mass on the greater curvature of the stomach (Figure 2a). Hemostasis was achieved with epinephrine and two hemostatic clips (Figure 2b). Gastric ulcer biopsy showed diffuse large B-cell lymphoma. Excisional biopsy of a left axillary lymph node showed large B-cell lymphoma. The patient received chemotherapy with rituximab, cyclophosphamide etoposide, vincristine, and prednisone (R-CHOP) with plans for continued oncology treatment and follow-up. DISCUSSION: Cases of gastric DBCL are rare.This case report highlights a patient who presented with gastrointestinal bleeding due to metastasis of DBCL to the stomach. DBCL is aggressive and first line treatment is with R-CHOP. Surgery is second-line treatment for cases with perforation and severe bleeding. Clinicians should consider metastatic DBCL as a rare cause of GI bleeding with other supportive findings such as lymphadenopathy. Earlier diagnosis and treatment of DBCL will lead to improved prognosis.Figure 1.: CT abdomen and pelvis shows extensive adenopathy.Figure 2.: Figure 2a. Bleeding ulcer on greater curvature of stomach.Figure 3.: Figure 2b. Hemostasis of ulcer with clips.