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

Other iatrogenic immunodeficiency-associated lymphoproliferative disorders (OIIA-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.