Are rheumatoid nodules specific for rheumatoid arthritis?

No. They are not pathognomonic for rheumatoid arthritis. They are seen in 5% to 7% of patients with systemic lupus erythematosus and in a rare condition in children called benign pseudorheumatoid nodules, in which the nodules grow rapidly and then spontaneously involute. These children are usually rheumatoid factor–negative, and some authorities feel that many of these cases represent deep GA. Another rare presentation is rheumatoid nodulosis, in which patients present with multiple rheumatoid nodules about the hands. They are rheumatoid factor-–positive but have a remarkably benign course.

McGrath MH, Fleischer A: The subcutaneous rheumatoid nodule, Hand Clin 5:127–135, 1989.