Gastrointestinal tract is the most common extranodal site for the development of non-Hodgkin lymphoma. The most frequently involved organ is stomach (55% to 75% of cases), followed by small bowel, large bowel, and esophagus. Infection (with H. pylori), celiac disease, inflammatory bowel disease and immunodeficiency states (congenital, HIV, iatrogenic) are the main predisposing factors. The most common type is diffuse large B-cell lymphoma (DLBCL), followed by extranodal marginal zone lymphoma (MALT lymphoma). The median age at presentation is 7th decade and clinical features include pain, anorexia, nausea, vomiting, weight loss, bleeding, diarrhea, and palpable mass. Many cases mimic gastritis or benign peptic ulcer clinically. This partial gastrectomy specimen is from an elderly male who presented with vague abdominal pain and weight loss. There is a single 5.8 cm ulcerated mass with transmural involvement. The morphologic and immunophenotypic features were diagnostic of DLBCL.