Cytomegalovirus (CMV) is an opportunistic pathogen causing different diseases in immunocompromised patients and leading to death in a high percentage of cases. CMV infection is also relatively frequent among patients with hematological malignancies, especially when treated with immunosuppressive agents. We describe the clinical history of a patient with stage IV diffuse large B-cell lymphoma (DLBCL) treated with eight courses of R-CHOP every two weeks, who presented clinical remission of the disease at the end of therapy. However, two months later he developed neurological symptoms due to cerebellar involvement and a subcutaneous dorsal lymphomatous infiltration. He had a partial response after chemotherapy and brain radiotherapy, but his clinical course was complicated by fever and hypotension. Although the fever resolved with broad-spectrum antibiotics, he presented progressive endocrine failure and died three weeks later. Autopsy confirmed disseminated multiorgan involvement by DLBCL associated with an unexpected CMV infection of the lungs and several endocrine organs including the pituitary gland, pancreatic islets and adrenals, a clinical association not previously reported in the English literature.