Very Low Dose Methotrexate-Induced Rheumatoid Nodules Localized in Buttocks and Palmar Aspects of Phalanges: Case Report

Rheumatoid nodules are the most common extra-articular lesions. They usually occur in rheumatoid factor positive patients and indicate activity and severity of the disease. These nodules characteristically occur subcutaneously on extensor surfaces over the elbows or other bony prominences. They may be overlooked if they occur in sites other than well-known areas. We present a case with rheumatoid arthritis (RA) who developed multiple subcutaneous, histologically-proven rheumatoid nodules in both buttocks as well as on palmar aspects of phalanges after 3.5 years of very low-dose weekly methotrexate (MTX) treatment. These nodules occurred abruptly while there was not active arthritis in any joint. MIX-induced large nodules may occur even with very low doses of MTX, in atypical localizations such as both buttocks.