Primary spleen lymphoma is a rare condition. It is a neoplasm of the non-Hodgkin subtype, involving the spleen and its hilar nodes, with a disease-free period of at least six months after surgical removal of the spleen. We present the case of a 55-year-old woman with a history of obesity and type 2 diabetes mellitus in treatment, who came to the consultation for presenting a mass in the abdominal region, of four months of evolution, associated with general syndrome, weight loss and abdominal discomfort. On the physical examination the patient was afebrile, with slight pain at palpation in hypochondrium and left flank, palpable spleen tip, no peripheral adenopathies and mucosal skin pallor. Analytical and imaging studies were performed. She was admitted to hospital with a presumptive diagnosis of lymphoproliferative syndrome (splenic lymphoma). Splenectomy was performed with the use of general orotracheal anesthesia. Pathology report was positive for diffuse large B-cell lymphoma. Adjuvant treatment with chemotherapy was applied. Five months after surgery, she had no evidence of lymphoma spread.