How does pituitary adenoma cause Cushing's syndrome (Hypercortisolism)?

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From the Guidelines

Pituitary adenomas cause Cushing syndrome by producing excessive amounts of adrenocorticotropic hormone (ACTH), leading to overproduction of cortisol by the adrenal glands, and the optimal treatment is surgical resection by selective removal of the adenoma, as recommended by the consensus guideline for the diagnosis and management of pituitary adenomas in childhood and adolescence 1. The excess ACTH produced by the pituitary adenoma stimulates the adrenal glands to overproduce cortisol, leading to the characteristic symptoms of Cushing syndrome, such as central obesity, moon face, buffalo hump, purple striae, muscle weakness, hypertension, glucose intolerance, and mood disturbances. Key factors that influence the success of surgical treatment include:

  • Identification of the adenoma at surgery
  • Younger age of the patient
  • Smaller size of the adenoma
  • Absence of cavernous sinus or dural invasion
  • Morning serum cortisol level of <1 μg/dl (<28 nmol/l) after surgery, as reported in the study 1. Selective adenomectomy is considered the first-line treatment of choice for Cushing disease, with a strong recommendation and moderate-quality evidence 1. Additionally, repeat surgery for persistent or recurrent disease may be considered, with a moderate recommendation and low-quality evidence, as stated in the guideline 1. It is essential to note that lifelong follow-up is crucial for children treated for Cushing disease, as recurrence can occur even after apparent surgical cure, as reported in the study 1.

From the Research

Cushing's Syndrome Caused by Pituitary Adenoma

  • Cushing's syndrome can be caused by a pituitary adenoma, which is a type of tumor that secretes excess adrenocorticotropic hormone (ACTH) 2, 3, 4.
  • This excess ACTH stimulates the adrenal glands to produce excess cortisol, leading to the symptoms of Cushing's syndrome 2, 4.
  • Pituitary adenomas are the most common cause of endogenous Cushing's syndrome, accounting for approximately 70% of cases 3, 4, 5.

Mechanism of Cushing's Syndrome

  • The pituitary adenoma secretes excess ACTH, which binds to receptors in the adrenal glands, stimulating them to produce excess cortisol 2, 4.
  • The excess cortisol then acts on various tissues in the body, leading to the symptoms of Cushing's syndrome, such as weight gain, hypertension, and glucose intolerance 2, 4.
  • The diagnosis of Cushing's syndrome caused by a pituitary adenoma involves a combination of clinical evaluation, laboratory tests, and imaging studies 2, 3, 4.

Treatment Options

  • The primary treatment for Cushing's disease caused by a pituitary adenoma is transsphenoidal surgery to remove the tumor 2, 3, 4.
  • Medical therapy, such as steroidogenesis inhibitors, may also be used to control the symptoms of Cushing's syndrome, especially in cases where surgery is not possible or has failed 3, 5.
  • Other treatment options, such as radiation therapy and bilateral adrenalectomy, may also be considered in certain cases 2, 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Cushing's disease.

Handbook of clinical neurology, 2014

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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