Sinus histiocytosis (Destombes-Rosai-Dorfman disease) revealed by extranodal spinal involvement

Sinus histiocytosis with massive cervical lymphadenopathy (Rosai-Dorfman disease) is a non-neoplastic lymphoproliferative disorder. Extranodal involvement, especially of the nervous system, is unusual. We report a case revealed by neurological symptoms. A 10-year-old girl presented with paraparesis due to a dural extramedullary mass on magnetic resonance imaging. Massive cervical lymphadenopathy appeared secondarily. Radiological investigations showed mediastinal, paranasal sinus and lower eyelid involvement. The diagnosis of Rosai-Dorfman disease was established histologically and by immunohistochemical studies of nodal lesions by the demonstration of characteristic sinus histiocytosis with sheets of S-100 protein and CD-68 positive large histiocytes displaying lymphocyte phagocytosis. A dramatic response occurred with complete resolution of all clinical findings after treatment with corticosteroids and etoposide, although neurological lesions were unchanged on magnetic resonance imaging. Despite its rarity, this case underlines the unknown pathogenesis of this disease (immune dysfunction?) and the difficulties of treatment (choice of chemotherapeutic agents, duration).