Cushing's syndrome is caused by elevated levels of cortisol, a key glucocorticoid hormone, over an extended period of time. The growth of a tumor on one of the two adrenal glands causes about 15% of all cases of Cushing's syndrome.

Adrenal tumors secrete cortisol and may be benign (noncancerous) or malignant (cancerous). Benign tumors that may cause Cushing's syndrme include adrenal adenomas or micronodular hyperplasia. Adrenal carcinomas are malignant tumors that may cause Cushing's syndrome.

Other causes of Cushing's syndrome are secretion of ACTH by a pituitary tumor, by another organ (ectopic Cushing's syndrome), and regular use of corticosteroids such as prednisone, commonly used to treat chronic conditions such as rheumatoid arthritis and asthma.

Although they may develop in anyone at any age, adrenal tumors are more common in adults -- 70% of all adrenal tumors occur in adults. They are found in women more often than men and are relatively rare, occuring in 6 out of every 1,000,000 people.

• Moon face (round, red, and full)
• Weight gain
  • Buffalo hump (a collection of fat between the shoulders)
  • Central obesity with protruding abdomen and thin extremities
• Skin changes
  • Thinning of the skin
  • Easy bruising
  • Acne or superficial skin infections
  • Purple striations on the skin of the abdomen, thighs, and breasts
• High blood pressure
• Weakness (often noticed when trying to stand up or to raise hand above head)
• Backache
• Headache
• Thirst
• Increased urination
• Mental changes, including euphoria not linked to a life event
• Cessation of menses in women

Other symptoms seen in men include the following:

• Breast development
• Impotence

Patients with adrenal carcinoma may also have symptoms of excess androgen, including excessive hair in unusual parts of the body (in women), acne, and scalp hair loss.

Tests to confirm Cushing's syndrome:

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

Tests to determine cause:

• ACTH (low normal or undetectable)
• High-dose dexamethasone suppression test
• Abdominal CT (may show adrenal mass)

Other findings may include:

• Elevated fasting glucose
• Low serum potassium
• Low bone density by dual X-ray absorptiometry (DEXA)
• Elevated cholesterol

Cushing's syndrome due to an adrenal tumor is treated by surgical removal of the tumor (which often includes removal of the gland as well). Glucocorticoid replacement therapy is usually required until the other adrenal gland recovers from surgery. Nine to 12 months of glucocorticoid therapy may be required.

If surgery is not possible, particularly with cases of adrenal carcinoma, medications can suppress the secretion of cortisol:

• Mitotane
• Ketoconazole
• Aminoglutethimide
• Metyrapone

Radiation therapy is rarely effective in patients with adrenal carcinoma and is usually not appropriate for adrenal adenoma.

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

For adrenal carcinoma, surgery is sometimes not possible. When surgery is performed, it does not always cure the cancer. Survival time ranges from 14 to 36 months after diagnosis of adrenal carcinoma.

Adrenal carcinoma can result in metastasis (spread) of the tumor to the liver or lungs.

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

Use caution when taking corticosteroid medications.

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