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
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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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