Necrobiosis lipoidica-like skin lesions in systemic sarcoidosis

A 62-year-old woman with systemic sarcoidosis developed erythematous plaques on her lower legs. Clinically, two kinds of skin lesions were distinguished; one type formed brownish-red plaques with induration suggesting plaque-type skin sarcoid, and the other formed purplish erythematous plaques with atrophic centers resembling necrobiosis lipoidica. In spite of this clinical appearance, a biopsy specimen from one of the latter lesions revealed typical skin sarcoid histology composed of discrete non-caseating granulomas, while that from one of the other lesions showed necrobiotic changes of collagen bundles surrounded by epitheloid histiocytes and foreign-body giant cells. Because cutaneous involvement of sarcoidosis may mimic necrobiosis lipoidica clinically and/or histologically, we diagnosed her skin lesions as necrobiosis-like skin sarcoid.