RESUMO
Rheumatoid arthritis (RA)is a multisystemic inflammatory disease with a prevalance of approximately 1%of the population.The use of disease modifying anti-rheumatic drug (DMARD)is an essential regimen for the treatment of RA. Among DMARDs,methotrexate (MTX)is used worldwide with confirmed effectiveness.However,cytopenia,pulmonary injury,and hepatic toxicity are a few side effects limiting its use.In addition,although the oncogenic potential of MTX is low,several cases have been reported.Recently an increased risk of developing lymphoproliferative disorders has been reported in patients with RA. The incidence is higher in elderly individuals with severe longstanding seropositive RA,those with Sjogren's or Felty's syndrome,and in patients with RA treated with prolonged low dose MTX.We describe a case of RA who developed non-Hodgkin's lymphoma during low dose MTX therapy.