Sinus histiocytosis of the thyroid with massive lymphadenopathy (Rosai-Dorfman disease).

A 63-year-old woman presented with a midline neck swelling which clinically appeared as goitre with bilateral cervical lymphadenopathy. Pre-operative investigations were suggestive of malignancy with lymph node metastasis for which a subtotal thyroidectomy with lymph node excision was done. But the histopathological examination of the operative specimen was reported as sinus histiocytosis of the thyroid and the cervical lymph nodes.