Ectopic ACTH syndrome due to salivary gland adenoid cystic carcinoma.

A 68-year-old woman developed Cushing syndrome associated with a submaxillary salivary gland adenoid cystic carcinoma. High levels of immunoreactive adrenocorticotrophic hormone (ACTH) were found in the tumor and peripheral blood. Urinary 17-hydroxycorticosteroid levels decreased following administration of dexamethasone, suggesting possible suppression of ectopic ACTH production. however, there was no specific in vitro binding of dexamethasone by tumor cytosol. A trial of metyrapone therapy resulted in control of hypokalemia and hyperglycemia. Both plasma cortisol and 11-deoxycortisol levels decreased with metyrapone administration, suggesting that this agent may inhibit not only 11-beta-hydroxylation, but also possibly earlier steps in glucocorticoid synthesis.