Other iatrogenic immunodeficiency-associated lymphoproliferative disorders of the oral floor induced by methotrexate and tofacitinib: A case report

Other iatrogenic immunodeficiency-associated lymphoproliferative disorders (0IIA-LPDs), which are uncontrolled lymphoid proliferation or lymphoma induced by immunosuppressive medication, arise mainly in patients with rheumatoid arthritis (RA). The vast majority of OIIA-LPDs are caused by methotrexate (MTX), and the reported incidence rates in the oral and maxillofacial regions are similar to those in other organs. In addition, tofacitinib (TFC), which is a Janus kinase inhibitor, has been clinically applied for the immunosuppressive treatment of RA in recent years. Herein, we present a case of OIIA-LPD of the oral floor in a patient with RA who had been treated with TFC and MTX. Clinical and pathological findings suggested that inflammatory stomatitis and/or infective response by oral bacteria promoted lymphoid activation in the oral mucosa, which could potentially become malignant. This case report indicates that OIIA-LPD might result from the combined usage of MTX and TFC, and a synergistic influence between MTX and TFC on immunosuppression may lead to diversification of OIIA-LPDs. The findings suggest the difficulty in controlling complications of RA and the importance of understanding the mechanisms of immunosuppressive treatments. (C) 2020 Asian AOMS, ASOMP, JSOP, JSOMS, JSOM, and JAMI. Published by Elsevier Ltd. All rights reserved.