Cutaneous sarcoidosis clinically mimicking necrobiosis lipoidica in a patient with systemic sarcoidosis.

A 70-year-old woman with an 8-year history of systemic sarcoidosis developed round, red-brown eruptions, with central atrophic lesions on her lower legs. The features of the biopsy specimen resembled those of necrobiosis lipoidica (NL), but although necrobiosis was present there were well-formed non-necrotizing granulomas in the dermis. The histological diagnosis was cutaneous sarcoidosis. Systemic sarcoidosis presenting with NL has rarely been reported. The histological features of cutaneous sarcoidosis sometimes mimic those of other granulomatous diseases, including NL and granuloma annulare, which are difficult to distinguish. We discuss the novel association between sarcoidosis and other granulomatous diseases.