Rosai-Dorfman disease: two case reports and diagnostic role of fine-needle aspiration cytology.

Rosai-Dorfman disease, or sinus histiocytosis with massive lymphadenopathy (SHML), is a rare and self-limiting benign disorder that most commonly involves the cervical lymph nodes. The authors describe two cases of SHML. Fine-needle aspiration of the lymphadenopathy was performed in both patients. Immunocytochemical and histologic features, as the evidence of emperipolesis and S100 protein positivity on immunostaining, were typical of SHML. Fine-needle aspiration cytology plays an important diagnostic role in SHML and may be conclusive in a typical clinical setting. The diagnosis of SHML should be considered in the differential diagnosis of massive, painless cervical lymphadenopathy. Long-term follow-up is necessary to observe the complete regression of the massive lymphadenopathy. However, specific therapy is available and should be limited to patients with compressive symptoms or extranodal disease.