Non-Functioning Adenoma (Endocrine-Inactive Adenoma): ): Pituitary adenomas that do not produce excess hormones. Instead they typically cause symptoms due to pressure on the normal pituitary gland and/or structures around the pituitary such as the optic nerves and optic chiasm, leading to headaches, visual loss and pituitary failure. Primary treatment of symptomatic non-functioning adenomas is endonasal endoscopic removal. Learn more.