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Pituitary tumor

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Pituitary tumor

Definition:

A pituitary tumor is an abnormal growth in the pituitary gland, the part of the brain that regulates the body's balance of hormones.

Alternative Names:

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Tumor - pituitary

Causes, incidence, and risk factors:

The pituitary gland is a pea-sized endocrine gland located at the base of the brain. The pituitary regulates and controls the secretion of hormones from other endocrine glands, which in turn regulate many body processes. These hormones include the following:

• Growth hormone (GH)
• Thyroid-stimulating hormone (TSH)
• Adrenocorticotrophic hormone (ACTH)
• Prolactin

About 75% of pituitary tumors secrete hormones. When a tumor produces excessive amounts of one or more hormones, the following conditions may occur:

• Giantism or acromegaly (excess growth hormone)
• Hyperthyroidism (excess thyroid stimulating hormone)
• Cushing's syndrome (excess adrenocorticotropic hormone)
• Prolactinoma (excess prolactin)

As the tumor grows, destruction of some of the hormone-secreting cells of the pituitary may take place, causing symptoms related to the underproduction of the hormone that is suppressed (hypopituitarism).

The causes of pituitary tumors are unknown, although some are a part of a hereditary disorder called multiple endocrine neoplasia I (MEN I).

There are other types of tumors that can be found in the same area of the head as a pituitary tumor:

• Craniopharyngiomas
• Germinomas
• Cysts
• Metastatic tumors (tumors that have spread from cancer in another part of the body)

About 15% of tumors located within the skull are pituitary tumors. Most pituitary tumors are located in the anterior pituitary lobe and are usually beningn (noncancerous). Pituitary tumors develop in 1 in 10,000 people.

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