Thyroid hormone resistance and pituitary enlargement after thyroid ablation in a woman on levothyroxine treatment.
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Marazuela M, Nattero L, Moure D, Garcia-Polo I, Figueroa-Vega N, Guijarro C
Thyroid hormone resistance and pituitary enlargement after thyroid ablation in a woman on levothyroxine treatment.
Thyroid. 2008 Oct;18(10):1119-23. doi: 10.1089/thy.2007.0375.
- PubMed ID
- 18816177 [ View in PubMed]
- Abstract
We report a patient with inappropriate secretion of thyrotropin (TSH) and a pituitary mass. Although she had been treated for biochemical hyperthyroidism with thyroid surgery and radioiodine ablation, she had never complained of specific symptoms or demonstrated signs of overt thyroid dysfunction. On evaluation, she had increased free thyroxine and TSH levels, normal serum glycoprotein alpha-subunit levels, and a significant TSH over-response to exogenous thyrotropin-releasing hormone stimulation. Magnetic resonance imaging with gadolinium enhancement showed a pituitary enlargement with suprasellar extension. An indium In 111 pentetreotide scan showed an abnormal focus of radionuclide accumulation in the pituitary area. Sequencing of the TRbeta gene showed that the patient was heterozygous for a new single nucleotide substitution resulting in the replacement of the normal arginine with a serine at amino acid 320 (R320S). We review the difficulties encountered in establishing a correct diagnosis in patients with inappropriate secretion of TSH in combination with pituitary enlargement. Due to its possible false-negative results, we do not recommend the use of indium In 111 pentetreotide as a tool in the differential diagnosis of inappropriate secretion of TSH.
DrugBank Data that Cites this Article
- Drug Targets
Drug Target Kind Organism Pharmacological Action Actions Levothyroxine Thyroid hormone receptor beta Protein Humans YesAgonistDetails Liotrix Thyroid hormone receptor beta Protein Humans YesAgonistDetails