Transition from Pituitary-Dependent to Adrenal-Dependent Cushing's Syndrome

PITUITARY-DEPENDENT bilateral adrenocortical hyperplasia (Cushing's disease) is present in 70 to 80 percent of all patients with Cushing's syndrome. In 20 to 40 percent of patients with Cushing's disease, macroscopic adrenocortical nodules, surrounded by hyperplastic cortical tissue, are found, usually in both adrenal glands (macronodular hyperplasia).1 Most probably, macronodular hyperplasia is a later stage of diffuse hyperplasia, developing under the influence of long-standing endogenous hyperadrenocorticotropinism.1 In recent years it has been shown that in some patients with pituitary-dependent Cushing's syndrome, a unilateral adrenal nodule suggestive of a cortical adenoma can develop.2 3 4 5 It has been postulated, but never conclusively demonstrated, that . . .