Anaplastic carcinoma of the thyroid: a clinicopathologic study of 82 cases.

Anaplastic carcinoma of the thyroid accounts for about 10% to 15% of all thyroid carcinomas in the United States. Its lethality is evidenced by a 5-year survival rate of 3.6% and a median survival of 4 months. Rapid growth of a thyroid mass, frequently in a preexisting goiter, is the most common manifestation; the diagnosis should be considered and expeditiously pursued in all patients who present with this finding. Relatively favorable prognostic features seem to be unilateral tumors, a tumor diameter of less than 5 cm, no invasion of adjacent tissue, and absence of nodal involvement. For resectable lesions, thyroid lobectomy with wide margins of adjacent soft tissue on the side of the tumor seems to constitute a safe, appropriately aggressive surgical approach. Total thyroidectomy and radical neck dissection results in an increased complication rate and has no advantage over a more conservative approach. Radiotherapy, chemotherapy, immunotherapy, and combination radiotherapy and chemotherapy need further evaluation.