Recently, methotrexate-associated lymphoproliferative disorders (MTX-LPD) in patients with rheumatoid arthritis (RA) have frequently been reported as a lymphoproliferative disorder developing in immunosuppressed patients. Many reports have indicated a relation between MTX-LPD and Epstein-Barr virus (EBV). We report 4 cases of EBV-positive MTX-LPD arising in the oral cavity. After consulting a hematologist, methotrexate (MTX) was discontinued in three patients, and one patient moved to another medical facility. Three lesions regressed after MTX withdrawal. However, one patient who resumed treatment with MTX had a relapse of LPD. A literature search on MTX-LPD in the oral cavity revealed a high positive rate of EBV, a good response to MTX withdrawal, a higher prevalence in women, and a high frequency of maxillary gum involvement.
