In west Africa, splenic lymphoma with villous lymphocytes and hyper-reactive malarial splenomegaly have many clinical and immunological features in common suggesting an aetiopathological link. We hypothesize that in hyper-reactive malarial splenomegaly the dysregulated immune response to repeated malaria infections results in a stimulated, proliferating pool of B cells in which perturbation of cell growth and apoptosis by environmental and other factors promotes the development of SLVL. In Africa these factors are likely to include infectious agents several of which have already been associated with B-cell non-Hodgkin's lymphomas.