Central Nervous System Methotrexate-associated Lymphoproliferative Disorder in a Patient with Rheumatoid Arthritis : Two Case Reports

Abstract

  Methotrexate-associated lymphoproliferative disorder (MTX-LPD) is an iatrogenic disorder that develops during low-dose methotrexate (MTX) therapy. Two patients who had been treated with MTX for rheumatoid arthritis showed multiple lesions with ring contrast enhancement in the cerebrum on head magnetic resonance imaging. We performed an open biopsy, and histopathological examination showed the presence of Epstein-Barr virus-positive diffuse large B-cell lymphoma. The patients were diagnosed with MTX-LPD induced by low-dose MTX therapy. The lesions regressed after MTX discontinuation. Although MTX-LPD is mainly composed of extra-nodal lesions, MTX-LPD in the central nervous system is rare. Since this disease is likely to be improved simply by discontinuing MTX, it is important to recognize this disease and to make a diagnosis by biopsy as promptly as possible.