2017 Volume 110 Issue 11 Pages 773-779
Methotrexate (MTX) is mainly used for the treatment of rheumatoid arthritis (RA), and is a widely used anchor drug for RA treatment. In this study, we encountered a case of methotrexate-associated lymphoproliferative disorder (MTX-LPD) in a patient who had a tumor in her upper gingiva. The patient was a 64-year-old woman, and she had been taking MTX orally for the treatment of RA. A swelling in her left cheek was her chief complaint at the time of her admitance to our medical center. We conducted a tissue biopsy as we suspected an upper jaw cancer, but the results indicated granulomatous changes because of chronic inflammation. As we could not rule out the possibility of malignancy, we conducted a second tissue biopsy, and, this time performed immunostaining. The results confirmed the presence of EBER-positive cells in addition to, CD20, CD79a and CD3 positivity. Based on these results, we diagnosed her as having MTX-LPD and suspended her intake of MTX. In the two months following the suspension of MTX, her cheek swelling improved, and an MRI examination confirmed the disappearance of the tumor. A sequestration of the jawbone persisted and was subsequently removed surgically. When a patient who has been taking MTX develops a tumor in the head or neck, careful examination and treatment, taking the possibility of MTX-LPD into consideration, is needed.
