Sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease): report of two cases with fine-needle aspiration cytology.

Sinus histiocytosis with massive lymphadenopathy (SHML) or Rosai-Dorfman disease is a rare but well-defined histiocytic proliferative disorder. There are only few reports or small series of cases on the fine-needle aspiration (FNA) cytologic features of this entity. Our first case was a 14-yr-old girl who presented with low-grade fever and neck swellings of 2 mo duration. FNA smears from the submandibular and cervical lymph nodes showed numerous histiocytes with evidence of lymphophagocytosis (emperipolesis) against a background of reactive lymphoid cells. The FNA cytodiagnosis was Rosai-Dorfman disease. The patient was put on steroids, with improvement. The second patient was a 3(1/2)-yr-old girl who presented with fever and left cervical lymphadenopathy. The initial FNA smear from an outside laboratory was reported as reactive hyperplasia. A repeat FNA smear showed numerous histiocytes with evidence of emperipolesis, mild nuclear enlargement and multilobation/multinucleation in a few histiocytes, and reactive lymphoid cells. The cytodiagnosis was Rosai-Dorfman disease. Review of the initial smear showed the Rosai-Dorfman (RD) cells, but in smaller number. We conclude that FNA cytology is a useful tool in the diagnosis of SHML, but the diagnosis may be missed at initial stages when characteristic cytomorphologic features are not well-developed.