Oral and maxillofacial manifestations of methotrexate-associated lymphoproliferative disorder in a patient with rheumatoid arthritis: Report of a case

Abstract Methotrexate (MTX) is a commonly used medicine treating rheumatoid arthritis (RA), and occasional patients receiving MTX are known to have lymphoproliferative disorders(MTX–LPDs). MTX–LPDs involving widely the maxillofacial region have been rarely documented, though those limited in the oral cavity are not so rare. We herein report a 63-year-old Japanese woman with RA, who had received MTX and developed maxillofacial lesions with lymph-node swelling as MTX–LPD. She had subcutaneous masses around her nasolabial sulcus in addition to a submucosal mass of the right side of the palate, which were similarly and homogeneously enhanced with contrastive media together with cervical, inguinal, and axillary lymph nodesin computed tomography. In biopsy, the palatal mass showed a nodular proliferation of CD20-positive large atypical lymphocytes without Epstein-Barr viral infection signals replacing the mucous gland, which resembled that seen in diffuse large B-cell lymphoma. Under the diagnosis of MTX–LPD, MTX was discontinued for four months, and those mass lesions and the swollen lymph nodessimultaneously disappeared. These findings suggest that observation after MTX withdrawal should be tried in the treatment of patients with MTX–LPD arising in the background of RA, even if the clinicopathological findings are suggestive of malignant lymphoma. This is a report describing comprehensive clinicopathological data of an oromaxillofacial MTX–LPD case with simultaneous lymphadenopathy.