Interstitial Granulomatous Dermatitis -A Case Report Associated with Rheumatoid Arthritis

Interstitial granulomatous dermatitis is a rare entity first described by Ackerman et al. in 1993. We described a 57-year-old female, with a long-standing history of rheumatoid arthritis, presenting with symmetric violaceous to erythematous indurated papules and nodules on her buttock and medial thighs arranging in an arciform fashion for more than three months. Pathologically, it showed palisaded granulomas containing degenerated collagen, predominantly lymphohistiocytic infiltration with scattered eosinophils leading to dermal fibrosis. Some atypical histiocytes were also present. Combining the clinical and pathological pictures, interstitial granulomatous dermatitis was diagnosed.(Dermatol Sinica 23: 91-95, 2005)