A report of Epstein-Barr virus–positive primary cutaneous natural killer–/T-cell lymphoma

We describe a patient who presented with Epstein-Barr virus–positive tumor-stage primary cutaneous lymphoma. Our patient had previously been treated with oral methotrexate for long-standing rheumatoid arthritis. Tissue analysis revealed large tumor cells that were surface CD2- and CD3-positive; T-cell–restricted intracellular antigen–positive; CD56-, CD20-, and CD30-negative; and stained positively for Epstein-Barr virus. Our case is noteworthy for several reasons. Although the presence of rheumatoid arthritis and therapy with methotrexate are putative risk factors for the development of immune suppression-related and Epstein-Barr virus–related lymphomas, the vast majority of lymphomas in this setting are of B-cell origin, and rarely are these primary cutaneous in nature. In addition, our patient's tumor displayed an unusual phenotype, with immunophenotypic features suggestive of an atypical natural killer–/T-cell lymphoma. Methotrexate was withdrawn, and our patient was successfully treated with local radiotherapy. She has remained in complete remission 28 months since diagnosis.