Methotrexate-related lymphoproliferative disorder arising in the gingiva of a patient with rheumatoid arthritis.

Methotrexate (MTX) is the primary drug used in the management of rheumatoid arthritis (RA) and other immune-mediated inflammatory diseases. MTX is a strong immunosuppressive agent and has been reported to cause iatrogenic immunodeficiency-associated lymphoproliferative disorders (LPDs). Stomatitis caused by MTX-related cytotoxicity may occur, but gingival MTX-related LPDs are rare. In this article we present a case of gingival MTX-related LPD in a 60-year-old male with RA. The local findings of the gingival ulceration and alveolar bone exposure were similar to those of bisphosphonate-related osteonecrosis of the jaw. However, he had never received bisphosphonate therapy. The biopsy specimen of the gingival lesion was diagnosed as diffuse large B-cell lymphoma with Epstein-Barr virus positivity. Immediate withdrawal of MTX resulted in marked remission of the LPD.