Methotrexate-induced cutaneous B-cell lymphoma masquerading as facial cellulitis

Abstract Objective To describe a case of methotrexate-induced cutaneous B-cell lymphoma presenting as facial cellulitis to focus on the importance of considering a wide differential and expediting biopsy. Method Case Report and Literature Review. Case report We report a case of an 89 year old gentleman who presented with central facial skin involvement of what appeared to be an extensive cellulitis of infectious etiology which was not responsive to treatment. After much investigation, a link was made between his long-term methotrexate use and the risk for cutaneous lymphomas. A cutaneous biopsy was able to confirm thdis diagnosis. Literature review Over the past 20 years, a rising trend has been noted in the incidence of lymphoma, including cutaneous forms, in patients who have rheumatoid arthritis treated with long-term methotrexate. This rare but serious complication has been hypothesized to be secondary to both increased immunosuppression with genetic predisposition and increased frequency of latent infections such as Epstein-Barr Virus (EBV). Most of the reported cases describe complete regression of these malignancies with cessation of methotrexate use. However, the diagnosis can be difficult to ascertain due to the rarity and infectious appearing nature of the disease. Conclusion Methotrexate-associated cutaneous B-cell lymphoma is an entity that should be considered in patients who present with the appearance of facial cellulitis and are on long-term methotrexate therapy.