A case of granulomatous myositis in a patient with rheumatoid arthritis receiving anti-TNF-α treatment.

A 66-year old woman with a 14-year history of rheumatoid arthritis (RA) and uveitis was admitted to our department for evaluation of a mass in the left neck. Fourteen months prior to this admission the patient was started on golimumab. Serum creatine kinase (CK) level was elevated and myositis-specific and -associated antibodies were negative. Manual muscle test showed weakness in the neck flexor, sternocleidomastoid and deltoid muscles. Magnetic resonance imaging (MRI) of the neck, erector muscle of spine, breech, thigh and lower thigh demonstrated high-intensity lesions in the muscles in short-tau inversion recovery images. Electromyography in the right deltoid detected fibrillation potentials. Muscle biopsy from the left neck mass showed granulomatous myositis. Muscle weakness improved and CK levels normalized after discontinuation of golimumab. We report a case of granulomatous myositis under anti-TNF-α treatment for RA.