Association between thyroid function and serum cortisol in cortisol-producing adenoma patients

Area of Science:

• Endocrinology
• Internal Medicine
• Oncology

Background:

• Thyroid dysfunction is a known complication of hypercortisolism.
• Previous studies on thyroid function in cortisol-producing adenoma (CPA) patients have yielded inconsistent results.
• Excessive cortisol secretion can impact various endocrine axes, including the thyroid.

Purpose of the Study:

• To investigate the association between thyroid function and excessive cortisol secretion in patients with CPA.
• To explore the changes in pituitary function following adrenalectomy in CPA patients.
• To clarify the impact of cortisol-producing adenomas on thyroid hormone levels.

Main Methods:

• Retrospective study involving 94 CPA patients, 94 healthy controls (HC), and 94 nonfunctioning adrenal incidentaloma (NFAI) patients.
• Evaluation of serum thyroid stimulating hormone (TSH) and free thyroxine (T4) levels.
• Comparison of thyroid function parameters between CPA patients and control groups, with analysis of changes post-adrenalectomy.

Main Results:

• Serum TSH and free T4 levels were significantly lower in CPA patients compared to HC and NFAI groups.
• A positive trend was observed between serum cortisol levels and the prevalence of central hypothyroidism.
• Adrenalectomy led to the correction of decreased TSH and free T4 levels, indicating reversibility of thyroid axis dysfunction.

Conclusions:

• Patients with cortisol-producing adenoma exhibit decreased serum TSH and free T4 levels.
• The observed dysfunction of the hypothalamic-pituitary-thyroid axis in CPA patients appears to be reversible after surgical treatment.
• Adrenalectomy normalizes thyroid hormone levels, suggesting a direct impact of excess cortisol on thyroid regulation.