Pls see below. Cushing's disease is different than cushing's syndrome. Cushing's disease is caused by a tumor or enlargement (hyperplasia) of the pituitary gland. The best treatment is to take it out through surgery. If the surgery is incomplete, radiation treatment can then be used. Lastly, if these treatments are not successful, the adrenal glands may need to be removed to stop the production of cortisol.
Surgery. Best treatment option is to remove the pituitary adenoma (tumor) by resection trough the nose (transphenoidal resection) in the case of incomplete cure or relapse, another surgery or other treatments may need to be used. Currently, medical therapies are being looked at: pasireotide, Cabergoline to help to manage persistently elevated cortisol levels after surgery.