Depending on the cause, treatment can include surgery, irradiation, or pharmacologic interventions to reduce plasma cortisol levels without causing permanent damage to the anterior pituitary or adrenal glands.3 Surgery to remove a pituitary or adrenal tumor is performed with the goal of leaving the remaining endocrine tissue for continued function. Following surgery, the patient is placed on cortisol replacement therapy for 6 months to a year, or until adrenal function returns. If the entire pituitary gland or both adrenal glands are removed, the patient requires lifelong hormonal replacement.