Vasopressin-Responsive ACTH-Independent Macronodular Adrenal Hyperplasia Causing Cushing's Syndrome

ACTH-independent macronodular adrenal hyperplasia (AIMAH) is a rare cause of endogenous Cushing's syndrome (CS). The diagnosis is suggested by bilateral adrenal nodular enlargement on conventional imaging and the demonstration of ACTH-independent hypercortisolism. Cortisol secretion in AIMAH can be regulated by the aberrant adrenal expression of receptors for gastric inhibitory polypeptide, vasopressin, catecholamines, luteinizing hormone/human chorionic gonadotropin and serotonin. We report on a 47-year-old man with CS due to AIMAH. The cortisol levels were increased after vasopressin stimulation, suggesting aberrant expression of vaso-pressin receptor in the adrenal glands. Total adrenalectomy is considered a standard therapy for AIMAH.