Extranodal manifestation of Rosai-Dorfman disease without involvement of lymph nodes

BACKGROUND: Rosai-Dorfman disease is an uncommon sinus histiocytosis with massive lymphadenopathy. Rosai-Dorfman disease without lymphadenopathy is extremely rare. Extranodal pseudotumoral masses can occur--and have been identified and described--in the orbit, skin, bone, and upper respiratory tract. Because of its rareness, Rosai-Dorfman is seldom considered in the clinical differential diagnosis, particularly if extranodal manifestations predominate. METHODS AND RESULTS: We present herein a patient with extranodal manifestation of Rosai-Dorfman disease in the orbit and parotid without typical initial lymph node involvement that reacted on steroid therapy. CONCLUSIONS: The correct diagnosis of this entity with the knowledge that it can occur without lymphadenopathy is important. For these patients, diagnosis must be based on histologic and immunohistopathologic findings after surgical biopsy. Steroid therapy can be used for treatment.