Primary schwannoma of the thyroid gland involving the isthmus: report of a case.

Primary thyroid schwannomas are extremely rare tumors and there are very few reports of such tumors in the literature. This report presents a rare case of schwannoma involving the isthmus of the thyroid in a 47-year-old male, presenting as a symptomatic predominating cold nodule within a multinodular goiter. The patient underwent total thyroidectomy. The histological examination indicated an Antoni A-type schwannoma. The clinical, radiological and pathological findings of the tumor are discussed, emphasizing the difficulty in reaching a correct preoperative diagnosis. Only 18 cases of primary schwannoma of the thyroid gland have so far been described in the literature and, this is only the second report of thyroid schwannoma localized in the isthmus.