Cutaneous Rosai-Dorfman disease: a case report.

Rosai-Dorfman disease, otherwise known as sinus histiocytosis with massive lymphadenopathy, is a non-Langerhans cell histiocytosis with a benign course and unknown etiology. It was described in 1969 as a painless cervical lymph node enlargement in association with fever, weight loss and sweating. Extranodal disease has been reported in 43% of cases, with involvement of multiple organs. Purely extranodal Rosai-Dorfman disease has been already reported, including forms restricted to the skin. This paper reports a case of purely cutaneous Rosai-Dorfman disease, which is of interest in view of the rarity of this condition.