The ectopic ACTH syndrome.

Abstract

Summary The clinicopathological entity to which we have attached the name of the “ectopic ACTH syndrome” can no longer be considered a rarity. With increasing frequency it is recognized that certain tumors (arising in such diverse sites as the lung, liver, parotid, and even neural tissue) can sometimes produce a hormone that is biologically, physically, chemically, and immunologically indistinguishable from human pituitary adrenocorticotropic hormone (ACTH).2 Through its action on the adrenal glands this ectopic hormone can cause all of the chemical and clinical abnormalities of Cushing9s syndrome. Unlike pituitary ACTH, ectopic ACTH is not suppressible with dexamethasone. Ectopic ACTH is usually associated with a separate ectopic MSH, and occasionally it is produced in association with other ectopic hormones similar to gastrin, parathyroid hormone, or anti-diuretic hormone. It is tempting to speculate that many of the now obscure manifestations of malignancy might someday be understood in terms of the noxious effects of tumor products which are carried like hormones to other parts of the body where they exert unwanted effects.