A case of methotrexate-associated lymphoproliferative disorder accompanied by osteonecrosis of the maxilla

Methotrexate (MTX) is widely used to treat rheumatoid arthritis (RA), but methotrexate-associated lymphoproliferative disorder (MTX-LPD) has recently been occasionally reported. We encountered an MTX-LPD patient with the complication of osteonecrosis of the maxilla perforating the maxillary sinus. The patient was a 76-year-old female being treated with MTX and anti-TNFα antibody for RA. Chemotherapy was performed for the initial development of MTX-LPD in the upper gingiva after the withdrawal of MTX and anti-TNFα antibody. MTX-LPD remitted, but osteonecrosis reaching the maxillary sinus and its perforation developed, for which sequestrectomy was performed. The postoperative course was favorable without recurrence for 30 months.