Causes

Cushing syndrome is caused by constant, high levels of the steroid hormone cortisol. A tumor on one of the adrenal glands causes about 15% of all cases of Cushing syndrome. Adrenal tumors release cortisol.

Adrenal tumors may be noncancerous (benign) or cancerous (malignant).

Noncancerous tumors that may cause Cushing syndrome include:

• Adrenal adenomas
• Micronodular hyperplasia

Cancerous tumors that may cause Cushing syndrome include:

• Adrenal carcinomas

Adrenal tumors are rare. In children with high cortisol levels, adrenal tumors are more common than pituitary tumors or ectopic ACTH secretion. In adults, adrenal tumors are less likely to be the cause of high cortisol levels. Pituitary tumors (Cushing's disease) are more often seen in adults. Adrenal tumors are found in women more often than in men.

See also:

• Cushing's disease
• Cushing syndrome
• Ectopic Cushing syndrome
• Exogenous Cushing syndrome

Symptoms

Symptoms usually include:

• Upper body obesity (above the waist) and thin arms and legs
• Round, red, full face (moon face)
• Slow growth rate in children

Skin changes that are often seen:

• Acne or skin infections
• Purple marks (1/2 inch or more wide), called striae, on the skin of the abdomen, thighs, and breasts
• Thin skin with easy bruising

Muscle and bone changes include:

• Backache, which occurs with routine activities
• Bone pain or tenderness
• Collection of fat between the shoulders (buffalo hump)
• Rib and spine fractures (caused by thinning of the bones)
• Weak muscles

Women often have:

• Excess hair growth on the face, neck, chest, abdomen, and thighs
• Menstrual cycle that becomes irregular or stops

Men may have:

• Decreased or no desire for sex
• Impotence

Other symptoms that may occur include:

• Mental changes, such as depression, anxiety, or changes in behavior
• Fatigue
• Headache
• Increased thirst and urination

Exams and Tests

Tests to confirm Cushing syndrome:

• 24-hour urine sample to measure the following:
  • Urine cortisol
  • Urine creatinine
• Dexamethasone suppression test
• Serum cortisol levels

Tests to determine cause:

• Abdominal CT
• ACTH
• High-dose dexamethasone suppression test

Other findings may include:

• High cholesterol
• High fasting glucose
• Low bone density, seen by dual x-ray absorptiometry (DEXA)
• Low serum potassium

Treatment

Cushing syndrome due to an adrenal tumor is treated with surgery to remove the tumor and often the entire adrenal gland.

Glucocorticoid replacement treatment is usually needed until the other adrenal gland recovers from surgery. You may need this treatment for 9 - 12 months.

If surgery is not possible (such as in cases of adrenal cancer), medicines can be used to stop the release of cortisol. These include:

• Aminoglutethimide
• Ketoconazole
• Mifepristone
• Mitotane

Radiation therapy usually does not work for cancerous adrenal tumors and is not appropriate for noncancerous tumors.

Outlook (Prognosis)

Patients with an adrenal tumor who have surgery have an excellent outlook. Surgery success rates are very high with this type of tumor.

For adrenal cancer, surgery is sometimes not possible. When surgery is performed, it does not always cure the cancer.

Possible Complications

Cancerous adrenal tumors can spread to the liver or lungs.

When to Contact a Medical Professional

Call your health care provider if you develop any symptoms of Cushing syndrome.

Prevention

Appropriate treatment of adrenal tumors may reduce the risk of complications in some patients with tumor-related Cushing syndrome.

Alternative Names

Adrenal tumor - Cushing syndrome

References

Stewart PM, Krone NP. The adrenal cortex. In: Kronenberg HM, Melmed S, Polonsky KS, Larsen PR. Williams Textbook of Endocrinology. 12th ed. Philadelphia, PA: Elsevier; 2011:chap 15.

Updated: 4/11/2012

Reviewed by: Nancy J. Rennert, MD, Chief of Endocrinology & Diabetes, Norwalk Hospital, Associate Clinical Professor of Medicine, Yale University School of Medicine, New Haven, CT. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.