Treatment: Cushing’s syndrome of exogenous origin requires removal of the responsible agent. In most cases, this is difficult, because these patients often require the life-saving exogenous corticosteroids (e.g., after transplantation). In such cases, the practitioner should decrease the dose to the minimum possible or try to change to a different immunosuppressant. Cushing’s syndrome caused by adrenal adenoma or bilateral adrenal hyperplasia requires surgical removal. After removal of both adrenal glands, the patient will need replacement therapy. If the syndrome is caused by abnormal secretion of ACTH from a malignant tumor such as a small cell carcinoma of the lung, the patient is best served by treating the underlying tumor. Cushing’s disease is best treated by neurosurgical removal of the tumor, with consideration of postoperative radiotherapy.