Malignant thyroid teratoma: report of an aggressive tumor in a 64-year-old man.

Malignant teratoma of the thyroid is a rare and aggressive tumor, frequent in children than in adults. Histologically, thyroid teratomas usually show a predominance of a neuroectodermal component. Mature cartilage and bone may be present. We present the case of primary malignant teratoma of the thyroid in a 64-year-old man. Histologically, the tumor displayed a predominant neuroectodermal component. The diagnosis was confirmed by immunohistochemistry. The patient underwent a radical thyroidectomy with central neck dissection as primary treatment and radioiodine treatment afterwards. The patient had local and distant recurrence. A second surgery was performed with poor results and the patient died 3 months afterwards.