Malignant fibrous histiocytoma metastatic to the thyroid gland.

Despite frequent cancer metastases to the thyroid gland demonstrated at autopsy, finding of thyroid metastasis in clinical practice is rare. Malignancies most commonly metastasizing to the thyroid are malignant melanoma and carcinoma of the breast, kidney, and lung. Very little is known about thyroid metastases caused by sarcomas. Of these, malignant fibrous histiocytoma (MFH) is one of the most common in adults, with a high rate of metastases. A case of clinically significant thyroid metastasis from primary MFH involving the thigh visualized on I-123 thyroid imaging is reported.