Ectopic Cushing syndrome

Definition

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

Alternative Names

Causes

Cushing syndrome is the result of too much glucocorticoid hormones being released 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 release adrenocorticotropic hormone (ACTH). Other causes of Cushing syndrome are:

• Excess release of ACTH by the pituitary gland
• Long-term use of corticosteroid drugs (commonly used to treat conditions such as rheumatoid arthritis and asthma)
• Tumor of the adrenal gland

Tumors that can, in rare cases, release ACTH include:

• Islet cell tumors of the pancreas
• Medullary carcinoma of the thyroid
• Small cell tumors of the lung
• Tumors of the thymus gland

References

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.

Stewart PM. The Adrenal Cortex. In: Kronenberg HM, Melmed S, Polonsky KS, Larsen PR. Kronenberg: Williams Textbook of Endocrinology. 11th ed. Philadelphia, PA: Saunders Elsevier; 2008:chap 14.