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Challenging diagnosis of resistance to thyroid hormone in a patient with pituitary adenoma
  1. Nelson Carvalho Cunha1,2,
  2. Leonor Gomes1,2 and
  3. Margarida Bastos1,2
  1. 1 Serviço de Endocrinologia, Diabetes e Metabolismo, Centro Hospitalar e Universitario de Coimbra EPE, Coimbra, Portugal
  2. 2 Faculdade de Medicina da Universidade de Coimbra, Coimbra, Portugal
  1. Correspondence to Dr Nelson Carvalho Cunha, nelsoncarvalhocunha{at}


The elevation of thyroid hormone with a normal or elevated thyroid-stimulation hormone (TSH) occurs uncommonly. This set a diagnosis challenge between TSH-secreting pituitary adenoma and resistance to thyroid hormone (RTH). We report a case of a young female patient with palpitations, with elevated thyroid hormone and non-suppressed TSH. TSH receptor antibody was undetectable. Thyroid ultrasound revealed mild heterogeneous goitre, and MRI revealed a microadenoma with 7.5 mm length in pituitary’s left lobe. Pituitary hormones were within normal ranges. The thyrotropin-releasing hormone stimulation test showed normal TSH elevation, consistent with RTH. The genetic test revealed a mutation in heterozygosity in THRB gene (G344R) confirming RTH-beta. No pituitary surgery or thyroidectomy was performed nor were prescribed any antithyroid drugs. Inappropriate secretion of TSH requires a high level of clinical suspicion and the proper laboratory, genetic and radiological studies to conduct a correct diagnosis and prevent unnecessary and potential harmful therapies.

  • pituitary disorders
  • thyroid disease
  • genetics
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  • Contributors NCC helped in planning, conception, reporting, conduct, design, acquisition and interpretation of data. LG helped in planning, conception, acquisition and interpretation of data and review. MB reviewed the article.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Patient consent for publication Obtained.

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