We report a patient with common variable hypogammaglobulinemia and diffuse nodular lymphoid hyperplasia of the small intestine complicated by a jejunal malignant lymphoma. Immunopathological and histological studies showed a polymorphous centroblastic lymphoma with intracytoplasmatic IgM immunoglobulin and lambda light chains. Some mucosal nodules separate from the tumor mass showed atypical lymphoid cell populations similar to lymphoma cells, suggesting a transition between hyperplastic nodules and lymphoma nodules. Four similar cases, and six other patients with malignant lymphoma of the small intestine, associated with diffuse nodular lymphoid hyperplasia, but without immunodeficiency, have already been described. All these cases suggest that nodular lymphoid hyperplasia increases the risk of small intestine lymphoma.