Functioning primary thyroid carcinoma and metastases producing hyperthyroidism.

Abstract

ABSTRACT An unusual instance of hyperthyroidism due to primary and metastatic thyroid carcinoma is presented. Radioactive iodine scanning showed predominant uptake in the tumor, confirmed by radioautography, with suppression of function in the remaining normal tissue. During propylthiouracil treatment, the thyrotoxic state remitted while function of the previously suppressed normal tissue increased. These findings implicated the tumor tissue as the cause of the patient's hyperthyroidism. Though extremely rare, such cases emphasize the importance of careful observation of apparently benign hyperfunctioning nodules.