Cutaneous nodules in patients with rheumatoid arthritis: a case report and review of literatures.

We report a case of 57-year-old Japanese woman with an overlap syndrome of both rheumatoid arthritis (RA) and autoimmune hepatitis, who developed multiple skin nodules. An extensive biopsies of the nodules revealed rheumatoid neutrophilic dermatitis, showing panniculitis without vasculitis, combining with granulomatous formation histopathologically. Since cutaneous nodules in patients with RA are very complex, differential diagnosis should be done according to disease activities, medications used, and pathological findings. We suggest that the differences in histopathological findings of cutaneous nodules in patients with RA depend on their immunological conditions based on disease activities including therapeutic effects.