Ectopic Cushing's syndrome

Alternative names:

Cushing's syndrome - ectopic

Definition:

A condition caused by an adrenocorticotropic hormone (ACTH)-secreting tumor outside the pituitary or adrenal glands.

Causes, incidence, and risk factors:

Cushing's syndrome is due to excess glucocorticoid hormones being secreted over a long period of time. 15% of Cushing's syndrome cases are ectopic Cushing's syndrome. Ectopic Cushing's syndrome is caused by tumors that secrete adrenocorticotropic hormone (ACTH). Other causes of Cushing's syndrome are oversecretion by the pituitary gland of ACTH, a tumor of the adrenal gland, or by chronic administration of corticosteroid drugs commonly used to treat conditions such as rheumatoid arthritis and asthma. Oat cell tumors of the lung, thymomas (tumors of the thymus), islet cell tumors of the pancreas, medullary carcinoma of the thyroid, and pheochromocytoma are tumors that can secrete ACTH, although this occurs rarely. The incidence of ectopic Cushing's syndrome is 1 out of 100,000 people, but is very rare in children.