Cushing's syndrome.

Cushing's syndrome (CS) results from prolonged exposure to elevated endogenous cortisol. Majority of cases are caused by ACTH, pituitary, or ectopic origin. Primary adrenal hypersecretion is 15-20% caused by adenomas, carcinomas (ACC), and rarely by nodular adrenocortical disease. CS presents with all typical features. Commonly recommended initial testing are urinary free cortisol, late-night salivary cortisol, and 1-mg overnight dexamethasone suppression test (DST). Imaging is the key to diagnosis. CS continues to pose diagnostic and therapeutic challenges; life-long follow-up is mandatory.