Thyroid hormone resistance syndrom: difficulties in differential diagnosis

Abstract

Thyroid hormone resistance syndrome (RTH) is a rare disorder characterized by reduced peripheral tissue responses to thyroid hormones (TH) and elevated levels of circulating free thyroid hormones. Resistance to thyroid hormone is caused by mutations of the thyroid hormone receptor beta (THRB) gene. In this article, we present case of 26-years-old women who presented with unclear signs and symptoms. Thyroid morphology and function were evaluated with standard ultrasound of the thyroid, scintigraphy and cytological specimen obtained by FNAB. The features of the basic assessment of thyroid status with an emphasis on the concept of “±feedback” of thyroid-stimulating hormone (TSH) and TH. A differential diagnosis of TSH-secreting pituitary adenoma and RTH was discussed. Heterozygous mutation p.P453T in the THRB gene was detected. Thus, the given clinical case demonstrates the necessity of the thorough examination of patients in identifying disorders of the principle of “±feedback”. The observation in dynamics is recommended.