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Updated: Dec 13, 2025

Endoscopic Endonasal Trans-sphenoidal Approach: Minimally Invasive Surgery for Pituitary Adenomas
Published on: January 17, 2018
Pituitary hyperplasia mimicking thyrotropin-producing pituitary adenoma in the patient with resistance to thyroid
Onnicha Suntornlohanakul1, Chutintorn Sriphrapradang2
1Endocrinology and Metabolism Unit, Division of Internal Medicine, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
Abstract:
The syndrome of inappropriate thyroid-stimulating hormone (TSH) secretion is characterized by high circulating thyroid hormone concentrations in the presence of non-suppressed TSH. After exclusion of the laboratory interference, TSH-secreting pituitary adenoma (TSHoma) or resistance to thyroid hormone-beta (RTH-β) should be suspected. The presence of a pituitary adenoma on the hypothalamic-pituitary imaging supports the diagnosis of TSHoma. However, the incidental findings of non-functioning pituitary adenomas may appear in patients with RTH-β. Abnormal MRI finding in the RTH-β patient also includes pituitary enlargement from thyrotroph hyperplasia. We herein reported a patient with inappropriate TSH secretion who has pituitary hyperplasia mimicking TSHoma. This case illustrates the diagnostic tests to distinguish an RTH-β from TSHoma.
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