Classic and Recent Etiologies of Cushing’s Syndrome

Endogenous Cushing’s syndrome can result from excess adrenocorticotropic hormone (ACTH; corticotropin) production by a pituitary adenoma (Cushing’s disease) or by ectopic tumors secreting ACTH or corticotropin-releasing hormone (CRH). ACTH-independent Cushing’s syndrome is caused by adrenocortical tumors or hyperplasias.