Anaplastic thyroid cancer and hyperthyroidism.

We report a rare case of thyrotoxicosis in a patient with anaplastic thyroid cancer. A 65-yr-old male presented with a 2-d history of rapidly enlarging neck mass and back pain. Physical examination revealed a large, hard thyroid mass and resting tachycardia. He did not have any symptoms suggestive of airway compression at presentation. Thyroid hormone levels were consistent with a hyperthyroid state. CT scan of the neck and thorax showed a heterogeneous mass replacing the thyroid, bilateral pulmonary nodules, and a metastasis with pathological fracture at the level of T-8. Technetium-pertechnetate scan failed to show any uptake in the region of the thyroid. Fine needle aspiration of the thyroid revealed anaplastic thyroid cancer. The patient was started on steroids and radiation therapy of his spine lesion. Brief surgical exploration of the thyroid revealed extensive local infiltration of adjacent neck tissues and marked tumor necrosis. Immunohistochemical stains of the tumor were positive for p53, thyroglobulin, and thyroid transcription factor-1. The tumor had an extremely aggressive course and the patient died of asphyxiation from severe airway compromise 11 d after his initial presentation.