A case of Rosai-Dorfman disease presenting as nasal polyp

Background: Rosai-Dorfman disease (RDD ; sinus histiocytosis histiocytosis with massive lymphadenopathy) is a rare histiocytic disorder of unknown etiology characterized by enlarged cervical lymph nodes, fever, leukocytosis, and hypergammaglobulinemia. We describe a case of RDD presenting as a nasal polyp. Case: A 50-year-old woman presented with a nasal obstruction for a year. Biopsy of the nasal polyp revealed massive histiocytic infiltration suggesting RDD, as confirmed by subsequent biopsies of the laryngeal polyp and swollen lymph nodes of the neck. Touch smear cytology of the cervical node distinctly showed emperipolesis of lymphocytes by histiocytes surrounded by small lymphocytes and plasma cells. They showed no cytologic atypia. Immunohistochemically, cells engulfing lymphocytes were positive for S 100 protein and CD 68. Engulfed lymphocytes include T and B cells. Conclusion: RDD is indicated by cytology showing emperipolesissurrounded by lymphocytes and plasma cells.