Case Report
Ifegwu Ibe*, Behdokht Nowroozi
Abstract
Sinus histocytosis with massive lymphadenopathy, aka Rosai-Dorfman disease (RDD) is a rare, non-hereditary, histiocytic proliferative disorder, usually involving lymph nodes but occasionally occurring in extranodal sites. Extranodal involvement can be seen prior to,concurrently with, or post-nodal disease. We report two cases of extranodal sinonasal Rosai-Dorfman disease with initial mass morphology resembling high-grade sarcomas, on intraoperative consultation. Histopathology revealed large atypical spindly histiocytes with scattered emperipolesis. Immunohistochemistry was useful to determine the nature of the masses as the large atypical cells were positive for S100 and histiocytic markers CD68 and CD163. Recognition of sinonasal presentation of extranodal Rosai-Dorfman disease and its ability to histologically mimic other spindle cell neoplasms ensures accurate diagnosis for treatment.