The pituitary gland is involved in the production of several essential hormones. Tumors arising from the pituitary gland itself are called adenomas or carcinomas. Pituitary adenomas are benign, slow-growing masses that represent about 10% of primary brain tumors. Pituitary carcinoma is the rare malignant form of pituitary adenoma. It is diagnosed only when there is proven spread (metastases) inside or outside the nervous system.
Most pituitary adenomas grow in the front two-thirds of the pituitary gland. These tumors are classified as “secreting” and “non-secreting.” A “secreting tumor” produces excessive amounts of hormones. Most pituitary tumors fall into this category; they are further classified by the type(s) of hormone they produce.
Symptoms are caused when the growing tumor pushes on surrounding structures. This pressure can result in headache, visual impairment, and behavioral changes.
Tumors can also either produce excessive amounts of hormone or limit how much hormone is produced. The hormones most commonly affected include: growth hormone (regulates body height and structure), prolactin (controls lactation, or milk production), sex hormones (control the menstrual cycle and other sexual functions), thyroid gland hormones (control the thyroid gland), adrenal gland hormones, and vasopressin (a hormone involved in water and electrolyte balance).
Symptoms of pituitary adenoma and pituitary carcinoma are identical.
Because the pituitary gland impacts so many of the body’s functions, a multi-disciplinary approach to tumor treatment is needed to ensure the best possible outcome.
Treatment of pituitary adenoma or carcinoma usually includes surgery to remove it. In some cases, however drug therapy may be used to reduce the size of the tumor without surgery. Radiation can be used to treat a persistent and/or recurring tumor that does not respond to medication, as long as the tumor is secreting hormone. For tumors that do not secrete hormone, radiation may be used following partial removal, or if the tumor was invasive. Replacement hormone therapy is often prescribed following surgery and/or radiation.
Pituitary tumors account for 9% to 12% of all primary brain tumors. They can occur at any age, but they are more common in older people. Women are more affected than men, particularly during the childbearing years.