Anaplastic large cell lymphoma in a patient with rheumatoid arthritis.

It is known that patients with rheumatoid arthritis (RA) have an increased risk for non-Hodgkin's lymphomas in comparison with the general population. Although increased risk of lymphoma is attributed to the disease activity, the drugs used in the therapy of RA may also cause increased risk of malignancy. Herein, we report on an RA patient who developed non-Hodgkin's lymphoma after methotrexate therapy and review the literature about it. A 74-year-old man with RA had been treated with low-dose methotrexate and subsequently developed anaplastic large cell lymphoma of the T-cell phenotype. Anaplastic large cell lymphoma has been reported rarely in rheumatoid arthritis.