Aplastic anemia: possible associations with lymphoproliferative neoplasms

Aplastic anemia (AA) may precede, co-occur, or follow a lymphoproliferative neoplasm. The best molecularly clarified scenario is that of concurrent AA and unsuspected (occult) T-cell large granular lymphocyte leukemia. Several reported cases of AA and concurrent small B-cell lymphomas/leukemias and Hodgkin lymphomas suggest also a possible link to simultaneous or preceding AA that might be sought in an antineoplastic immunological attempt to 'eradicate' the underlying malignant clone. The 'immuno-deregulatory' potential and the direct cytotoxicity of regimens used for lymphoma therapy might be able to trigger AA in cases evolving after lymphoma treatment too. Alternative explanations of AA associated with lymphoproliferative disorders might be particular (immuno-)genetic patient backgrounds predisposing to both AA and lymphoid neoplasms or exposures to environmental factors, increasing the risk for both diseases. Finally, the most common causal relationship of AA and lymphoma is that of immunosuppression- or allogeneous hematopoietic stem cell transplantation-associated posttransplantational lymphoproliferative disorders in AA patients, who are treated in the respective manner. As all above scenarios are differently (specifically) therapeutically approachable and accompanied by diverse outcomes, they should be actively sought for and diagnosed as precisely as possible. This review summarizes the current knowledge on associations between AA and lymphoproliferative neoplasms.