Ectopic Cushing syndrome

Ectopic Cushing syndrome is a condition in which a tumor outside the pituitary or adrenal glands produces the 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 lower potassium. Weight loss may be present due to underlying cancer.

Classic features of Cushing syndrome are:

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

Tests that may be done include:

• 24-hour urine for cortisol and creatinine
• Dexamethasone suppression test
• Serum cortisol
• Serum ACTH
• Fasting glucose
• Serum potassium

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.