[Cutaneous Rosai-Dorfman disease]

To investigate the clinicopathologic feature, immunophenotype and differential diagnosis of cutaneous Rosai-Dorfman disease (CRDD).

Clinical manifestation, morphologic features and immunohistochemical staining were studied in 8 cases of CRDD.

All 8 patients presented with multiple papules, nodules and/or coalescent patches or plaques distributing over the extremities or trunk, without lymphadenopathy or other systemic abnormalities. Microscopically, the lesions were located intradermally and/or subcutaneously. CRDD was characterized by the presence of S-100 positive histiocytic cells exhibiting emperipolesis, accompanying with infiltration of mixed inflammatory cells. Fibrosis, somewhere in vague storiform pattern due to stromal responses, with distribution of individual neutrophil microabscess was seen in cases with a long course of illness. Dilated vascular spaces in dermis containing numerous large typical histiocytes were seen in 2 cases.

CRDD is a benign, persistent proliferative disease of histiocytes. Systemic involvement is rare, outcome favorable. It should be differentiated from other types of histiocytosis, dermatofibrosarcoma protuberans, xanthoma and lymphoproliferative disorders. Immunohistochemical staining for S-100 protein and CD68 is helpful in making a correct diagnosis.