Lymphoma developing in a patient with rheumatoid arthritis taking low dose weekly methotrexate.

We describe the occurrence of a lymphoma in a patient with rheumatoid arthritis (RA) taking weekly oral pulse methotrexate (MTX) in low doses for 33 months. This occurrence may be coincidental. There may be an increased incidence of lymphoma in RA not treated with immunosuppressive medications. However, the increasing use of MTX warrants reporting unusual events, especially malignancy. It is possible that even the mild immunosuppression that occurs with MTX therapy places patients with RA at added risk for developing lymphoproliferative diseases.