Transsphenoidal surgery is performed to remove pituitary tumors, which are abnormal growths that develop in the pituitary gland. Pituitary tumors cause a variety of hormone problems and can grow large enough to compress important nerves and arteries of the brain. Most pituitary tumors are noncancerous and usually remain confined to the gland and surrounding tissues rather than spreading to other parts of the body as cancerous tumors might. Surgery may not be the first option for pituitary tumors and your doctor will focus on controlling its growth and managing your hormone levels with medication.