Cushing's syndrome is a debilitating endocrine disorder characterized by excessive cortisol levels in the blood which may be the result of a tumor of the pituitary gland, adrenal glands (located above the kidneys) or from tumors or cancer arising elsewhere in the body (ectopic ACTH producing tumors). Cushing's disease refers specifically to excessive ACTH secretion by a pituitary tumor (also called pituitary adenoma). The cause of Cushings Syndrome is a pituitary adenoma in over 70% of adults and in approximately 60-70% of children and adolescents. Most pituitary ACTH-secreting adenomas are small in size (microadenomas). Overall, Cushings Disease is relatively rare, affecting 10 to 15 of every million people each year, and most commonly affects adults aged 20 to 50 years. Women account for over 70% of cases.