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 RosaiDorfman 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. Keywords: Histiocytosis; Non-Langerhans-cell histiocytosis; Sinus histiocytosis Resumo: A doença de Rosai-Dorfman, também denominada histiocitose sinusal com linfadenopatia maciça, é histiocitose de células não Langerhans, idiopática e de curso benigno. Descrita em 1969, caracteriza-se por linfadenomegalia não dolorosa, sendo a cadeia cervical a mais envolvida, além de febre, perda de peso e sudorese. O envolvimento extranodal ocorre em 43% dos casos, em que múltiplos sítios podem ser acometidos. Já foram descritos casos exclusivamente extranodais, inclusive formas limitadas à pele. Relata-se um caso de doença de Rosai-Dorfman extranodal cutânea pura, devido à raridade dessa apresentação clínica.