Ectopic Cushing syndrome is a condition in which a tumor outside the pituitary or adrenal glands produces a hormone called adrenocorticotropic hormone (ACTH).

Cushing syndrome is the result of excess glucocorticoid hormones secreted over a long period of time. About 15% of Cushing syndrome cases are due to ectopic Cushing syndrome.

Ectopic Cushing syndrome is caused by tumors that secrete adrenocorticotropic hormone (ACTH). Other causes of Cushing syndrome are oversecretion of ACTH by the pituitary gland, a tumor of the adrenal gland, or long-term administration of corticosteroid drugs commonly used to treat conditions such as rheumatoid arthritis and asthma.

Small cell tumors of the lung, tumors of the thymus gland, islet cell tumors of the pancreas, and medullary carcinoma of the thyroid are tumors that can secrete ACTH, although this occurs rarely.

Ectopic Cushing syndrome tends to present with less dramatic features than classic Cushing syndrome, but with higher blood pressure and a lower potassium level. Weight loss may be present due to underlying cancer.

Classic features of Cushing syndrome are:

• Acne or minor skin infections
• Buffalo hump
• Central obesity (abdomen sticks out; arms and legs are thin)
• Headache
• Increased urination
• Impotence (in men)
• Menstrual cycle stops (in women)
• Mental changes
• Moon face (round, red, and full)
• Purple marks (striations) on the skin of the abdomen, thighs, and breasts
• Thirst
• Weakness

Tests that may be done include:

• 24-hour urine for cortisol and creatinine
• Blood tests to check ACTH, cortisol, and potassium levels
• Dexamethasone suppression test
• Fasting glucose
• MRI and CT scans to locate tumors

The best treatment for ectopic Cushing syndrome is surgical removal of the tumor. This is usually possible when the tumor is benign (noncancerous).

But many times, the tumor is cancerous and has spread to other areas of the body before the problem with cortisol production has been discovered. Surgery may not be possible in these situations. In this case, drugs to block cortisol production may be given.

Surgery to remove the tumor may lead to full recovery, but there is a chance that the the tumor will come back.

The tumor may spread or return after surgery. High cortisol levels may continue.

Call your health care provider if symptoms of Cushing syndrome appear.

Prompt treatment of tumors may reduce the risk in some cases. Many cases are not preventable.

Arnaldi G, Angeli A, Atkinson AB, et al. Diagnosis and complications of Cushing's syndrome: A consensus statement. J Clin Endocrinol Metab. 2003;88-5595-5602.