Pituitary Tumors

What Is It?

The pituitary gland is a pea-sized structure that is attached to the undersurface of the brain by a thin stalk. It is protected by a cradle of bone called the sella turcica, which is located above the nasal passages, almost directly behind the eyes. The pituitary gland sometimes is called the master gland because it produces hormones that regulate many bodily functions, including the production of:

  • Thyroid hormone

  • Sex hormones, such as estrogen and testosterone

  • Adrenalin

  • Growth hormone

  • Breast milk

  • Anti-diuretic hormone that helps control water balance

When tumors develop in the pituitary gland, they are usually small, localized, slow-growing masses that start in one type of hormone-producing pituitary cells. Although these tumors almost always are benign (noncancerous), they have the potential to cause significant symptoms by:

  • Producing too much of one of the pituitary hormones

  • Suppressing the normal function of other cells in the pituitary gland

  • Growing large enough to press on the nearby optic nerves (nerves that carry vision impulses from the eyes to the brain) or on parts of the brain itself

A pituitary tumor is classified as one of four main types, based on whether it overproduces pituitary hormones and the specific type of hormone produced:

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