Differentiated thyroid carcinoma in a girl with resistance to thyroid hormone management with triiodothyroacetic acid.

Thyroid hormone resistance syndrome is characterized by a reduced target tissue response to the action of thyroid hormone, which leads to high levels of free thyroxine and free triiodothyronine with non-suppressed levels of thyrotropin (TSH). Recently, three cases of papillary thyroid carcinoma associated with thyroid hormone resistance syndrome were published. The main challenge in this situation is the difficulty of maintaining the suppression of TSH levels without producing symptoms of hyperthyroidism. We present another case of an association of thyroid hormone resistance syndrome and papillary thyroid carcinoma, and we share our experience with 3,5,3'-triiodothyroacetic acid, which made possible an easier management of the carcinoma after surgery, maintaining the TSH levels suppressed despite the resistance to thyroid hormones.