Diagnosis of sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease) by fine needle aspiration cytology.

Sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease) is a rare benign disease of unknown etiology presenting with massive lymphadenopathy. We report four cases of this disease retrieved from the archives of cytopathology laboratory, BPKIHS, Dharan, Nepal, during the period of January 2002 to October 2007. The cytologic morphology revealed lymphocytes, plasma cells, and single to multinucleated histiocytes with well preserved lymphocytes in their cytoplasm (emperipolesis or lymphophagocytosis). It is concluded that FNAC is a useful and reliable tool for the diagnosis of sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease) and biopsy can be avoided in these patients, thereby reducing patient inconvenience and health care cost.