ABSTRACT
SUMMARY Resistance to thyroid hormone (RTH) coexisting with ectopic thyroid is rare. Here we report a case of RTH with ectopic thyroid. A ten-year-old girl had been misdiagnosed as congenital hypothyroidism and treated with levothyroxine since she was born. Ten-year follow-up showed that the elevated thyrotropin was never suppressed by levothyroxine and no signs indicating hyperthyroidism or hypothyroidism despite elevated FT3 and FT4 levels. Therefore the girl developed no defects in physical and cognitive development. Pituitary adenoma was excluded by magnetic resonance imaging. Ultrasonography did not find the thyroid gland in the normal place, while the thyroid scan found a large lingual thyroid gland. The octreotide inhibition test showed a reduction in thyrotropin by 41.98%. No mutation was detected in the thyroid hormone receptor (THR) β, THRα, thyrotropin receptor (TSHR), and GNAS1 genes. To our knowledge, it is an interesting RTH case coexisting with lingual thyroid.
Subject(s)
Humans , Female , Child , Receptors, Thyroid Hormone/genetics , Thyroid Hormone Resistance Syndrome/complications , Thyroid Dysgenesis/complications , Thyroxine/therapeutic use , Time Factors , Tongue Diseases/diagnostic imaging , DNA/isolation & purification , Thyrotropin/analysis , DNA Mutational Analysis , Follow-Up Studies , Thyroid Hormone Resistance Syndrome/genetics , Congenital Hypothyroidism/diagnosis , Diagnostic Errors , Thyroid Dysgenesis/genetics , Thyroid Dysgenesis/diagnostic imagingABSTRACT
Resistance to thyroid hormone (RTH) is a rare autosomal dominant hereditary disorder. Here in, we report two patients with RTH in whom differentiated thyroid cancer was diagnosed. Two patients were admitted to our clinic and their laboratory results were elevated thyroid hormone levels with unsuppressed TSH. We considered this situation thyroid hormone resistance in the light of laboratory and clinical datas. Thyroid nodule was palpated on physical examination. Thyroid ultrasonography showed multiple nodules in both lobes. Total thyroidectomy was performed. The pathological findings were consistent with papillary thyroid microcarcinoma. BRAFV600E mutation analysis results were negative. RTH is very rare and might be overlooked. There is no consensus on how to overcome the persistently high TSH in patients with RTH and differentiated thyroid cancer (DTC). Further studies are needed to explain the relationship between RTH and DTC which might be helpful for the treatment of these patients.
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Carcinoma, Papillary/surgery , Carcinoma, Papillary/complications , Carcinoma, Papillary/genetics , Thyroid Hormone Resistance Syndrome/complications , Thyroid Hormone Resistance Syndrome/genetics , Mutation , Thyroidectomy , Thyroid Neoplasms/surgery , Thyroid Neoplasms/complications , Thyroid Neoplasms/genetics , Thyroid Hormone Resistance Syndrome/surgeryABSTRACT
Resistance to thyroid hormone (RTH) is an autosomal dominant hereditary disorder that is difficult to diagnose because of its rarity and variable clinical features. The magnitude of RTH is caused by mutations in the thyroid hormone receptor beta (TRbeta) gene. We recently treated a 38-yr-old woman with RTH who had incidental papillary thyroid carcinoma. She presented with goiter and displayed elevated thyroid hormone levels with an unsuppressed TSH. She was determined to harbor a missense mutation of M310T in exon 9 of the TRbeta gene, and diagnosed with generalized RTH. This mutation has not yet been reported in Korea. RTH is very rare and easily overlooked, but should be considered in patients who present with goiter and elevated thyroid hormone levels with an unsuppressed TSH. The association between thyroid cancer and RTH needs further study.
Subject(s)
Adult , Female , Humans , Diagnosis, Differential , Exons , Mutation, Missense , Thyroid Gland/diagnostic imaging , Thyroid Hormone Receptors beta/genetics , Thyroid Hormone Resistance Syndrome/complications , Thyroid Hormones/blood , Thyroid Neoplasms/complicationsABSTRACT
Thyroid hormone resistance syndrome is a genetic disease determined by a mutation that modifies the configuration of the beta thyroid hormone receptor, affecting its T3 binding capacity. Increased T3 and T4, determined by a compensatory TSH elevation secondary to pituitary resistance, allows an euthyroid functional state in most of the cases. The coexistence of pregnancy and thyroid hormone resistance is uncommon. Therefore, the optimal diagnosis and treatment strategy has not been determined. We report a 32 years old woman with thyroid hormone resistance, that became pregnant. During her pregnancy, she wassupplemented with levothyroxine in doses of 50 to 60 ug/day and remained euthyroid. Fetal development and growth were normal.