Destructive Thyrotoxicosis in a Patient with Anaplastic Thyroid Cancer

Abstract

A 55-year-old man was admitted to our hospital with an anterior neck tumor, hoarseness, and dysphagia that had continued for a few weeks. He was diagnosed as anaplastic thyroid cancer by fine-needle aspiration cytology. He was treated by external radiation and chemotherapy, but left hemothorax developed and he died of respiratory failure on the 76th day in hospital. On admission, the levels of serum free triiodothyronine (FT3), free thyroxine (FT4), and TSH were 12.8 pg/ml, 4.2 ng/dl, and 0 μU/ml, respectively. The simultaneous thyroidal I-131 uptake rate was 1.2% at 24 hours. The levels of free thyroid hormones fell gradually without antithyroid drugs to result in hypothyroidism (FT3 0.8 pg/ml, FT4 0 ng/dl, and TSH 36 μU/ml). The rapid growth of anaplastic thyroid cancer seemed to be responsible for destructive thyrotoxicosis followed by hypothyroidism in this patient. © 1989, The Japan Endocrine Society. All rights reserved.