Abstract: 【Abstract】 Rosai-Dorfman disease （RDD） is a rare histiocytic proliferative disorder. The etiology and pathogenesis of RDD are still unclear, and may be associated with the activation of signal transduction pathways and inflammatory reactions induced by infection and immune dysfunction. CRDD is defined as the RDD involving only the skin. Histopathological examination of CRDD lesions shows that a large amount of histiocytes, lymphocytes and plasma cells infiltrate the dermis, and intact endocytosed lymphocytes can be observed in the cytoplasm of histiocytes, which is called emperipolesis. Immunohistochemical study shows that histiocytes are stained positive for S-100 and CD68, but negative for CD1a. The treatment of CRDD includes surgical excision, local therapy and systemic therapy. Lesions can subside spontaneously in some patients, and it usually has a favorable prognosis.

Key words: Histiocytosis, sinus, Cutaneous Rosai-Dorfman disease