Rheumatoid nodule.

Rheumatoid nodules are the most common extra-articular manifestation of rheumatoid arthritis. Dermatologist may be concerned with the diagnosis and management of rheumatoid nodules, although most patients will probably be under the care of a rheumatologist. This article focuses in clinical, pathogenic, diagnostic, and therapeutic aspects of rheumatoid nodules. Classic rheumatoid nodules commonly occur in genetically predisposed patients with severe, seropositive arthritis. However, they may appear in other clinical settings. Accelerated rheumatoid nodulosis, especially involving the hands, has been reported in patients receiving methotrexate, antitumor necrosis factor alpha biologic drugs or leflunomide therapy for rheumatoid arthritis. Rheumatoid nodulosis is characterized by multiple rheumatoid nodules, recurrent joint symptoms with minimal clinical or radiologic involvement, and a benign clinical course. Pseudorheumatoid nodules have been reported in healthy children. Although histologically almost indistinguishable from true rheumatoid nodules, some consider these lesions to be a form of deep granuloma annulare.