[Isolated Rosai-Dorfman disease]

A case of extranodal sinus histiocytosis with massive lymphadenopathy (ENSHML; Rosai-Dorfman disease) is reported. The patient presented with a history of intracranial tumour and exophthalmus. Clinical examination found a large mass in the left orbit and paranasal sinuses. Excisional biopsy showed a dense fibrous tissue with an infiltrate rich in macrophages. Further evaluation revealed a retroperitoneal mass with consecutive ureteral stenosis. Further histological and immunohistochemical investigation of the orbital mass, now in suspicion of a systemic disease showed an infiltrate of S-100-positive histiocytes and emperipolesis allowing the diagnosis of extranodal sinus histiocytosis. The correct histologic diagnosis was delayed due to the unusual and isolated extranodal localisation of the disease. The literature concerning extranodal manifestations of Rosai-Dorfman disease is reviewed. We suggest the additional evaluation of such rare and unusual cases in experienced reference centers.