1. Endonasal Endoscopic Surgery: Surgical removal is the primary means to achieve long term remission in Cushing's disease: at experienced pituitary tumor centers remission rates range from 80-90% for and 30-70% for invasive adenomas or macroadenomas. Because of improved visualization, the endonasal endoscopic approach is rapidly becoming the preferred method for removal of most pituitary adenomas, including ACTH secreting adenomas. Long-term follow-up with 24 hour urinary free cortisol levels every 6 months is essential to monitor for tumor recurrence which can occur in 5 10% of patien