Methotrexate (MTX) is a first-line systemic medication used to treat rheumatoid arthritis because of its immunomodulatory effects. However, MTX has also been linked to the development of lymphoproliferative disorders (LPD) in patients with rheumatoid arthritis. We describe a patient with long-standing rheumatoid arthritis treated with MTX who developed cutaneous Epstein-Barr virus (EBV)-positive B cell lymphoproliferative disease resembling grade III lymphomatoid granulomatosis localized to the right leg. The lymphomatoid process resolved with withdrawal of the MTX. The pathogenesis of iatrogenic lymphoproliferative disorder was most likely triggered by the rheumatoid inflammation and the immunosuppressing effects of MTX, which led to EBV reactivation. We recommend a trial of MTX discontinuation prior to considering chemotherapy in patients with rheumatoid arthritis treated with MTX who develop EBV-positive B cell lymphoproliferative disease resembling a high grade B-cell lymphoma.