Methotrexate related B lymphoproliferative disease in a patient with rheumatoid arthritis. Role of Epstein-Barr virus infection.

A 57-year-old woman receiving low dose methotrexate (MTX) for rheumatoid arthritis (RA) developed a B lymphoproliferative disease (LPD) that was initially considered as large cell non-Hodgkin's lymphoma of B cell phenotype. Epstein-Barr virus (EBV) cytotoxic latent membrane protein-1 (LMP-1) expression was found in some large cells. The lymphoproliferative disease reversed with MTX discontinuation and without chemotherapy. These EBV-associated LPD in patients with RA receiving MTX or other immunosuppressive agents seem to be similar to those triggered by EBV in transplant patients receiving cyclosporine A. MTX withdrawal and short followup should be considered before chemotherapy since spontaneous regression is possible.