Cutaneous Rosai-Dorfman disease: an uncommon cause of granulomatous inflammation

Rosai-Dorfman disease (RDD) is a benign idiopathic proliferative disorder. It commonly affects lymph nodes, but other organs can be involved. RDD limited to skin is rare. We report a 45-yearold Chinese man suffering from RDD. The first three skin biopsies revealed granulomatous inflammation. The diagnosis was made by the fourth skin biopsy, which showed a characteristic histology of large pale-staining histiocytes that exhibited emperipolesis and stained positive for S-100 protein. 45 S100