Pituitary tumor

Also known as: Tumor - pituitary

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.

Causes, incidence, and risk factors

Most pituitary tumors are noncancerous (benign). Up to 20% of people have pituitary tumors. However, many of these tumors do not cause symptoms and are never diagnosed during the person's lifetime.

The pituitary gland is a pea-sized endocrine gland located at the base of the brain. The pituitary helps control the release of hormones from other endocrine glands, such as the thyroid and adrenal glands. The pituitary also releases hormones that directly affect body tissues, such as bones and the breast's milk glands. These hormones include:

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

As the tumor grows, hormone-releasing cells of the pituitary may be damaged, causing hypopituitarism.

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

Other types of tumors that can be found in the same part of the head as a pituitary tumor:

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

Symptoms

Most pituitary tumors produce too much of one or more hormones. As a result, symptoms of one or more of the following conditions can occur:

• Hyperthyroidism
• Cushing syndrome
• Gigantism or acromegaly
• Nipple discharge

Symptoms caused by pressure from a larger pituitary tumor may include:

• Headache
• Lethargy
• Nasal drainage
• Nausea and vomiting
• Problems with the sense of smell
• Visual changes
  • Double vision
  • Drooping eyelids
  • Visual field loss

Rarely, these symptoms may occur suddenly and can be severe.

Signs and tests

Your health care provider will perform a physical examination. The provider will note any problems with double vision and visual field, such as a loss of peripheral vision or the ability to see in certain areas.

Endocrine function tests include:

• Cortisol levels:
  • Dexamethasone suppression test
  • Urine cortisol test
• Follicle-stimulating hormone (FSH) levels
• Insulin growth factor-1 (IGF-1) levels
• Luteinizing hormone (LH) levels
• Serum prolactin levels
• Testosterone/estradiol levels
• Thyroid hormone levels:
  • Free T4 test
  • TSH test

Tests that help confirm the diagnosis include the following:

• Formal visual field testing
• MRI of head

Treatment

Pituitary tumors are usually not cancerous and therefore won't spread to other areas of the body. However, as they grow, they may place pressure on important nerves and blood vessels.

Surgery to remove the tumor is often necessary, especially if the tumor is pressing on the optic nerves, which could cause blindness.

Most of the time, pituitary tumors can be removed through the nose and sinuses. However, some tumors cannot be removed this way and will need to be removed through the skull (transcranial).

Radiation therapy may be used to shrink the tumor, either in combination with surgery or for people who cannot have surgery.

The following medications may shrink certain types of tumors:

• Bromocriptine or cabergoline are the first-line therapy for tumors that release prolactin. These drugs decrease prolactin levels and shrink the tumor.
• Octreotide or pegvisomant is sometimes used for tumors that release growth hormone, especially when surgery is unlikely to result in a cure.

Support Groups

The Pituitary Network Association --

Expectations (prognosis)

If the tumor can be surgically removed, the outlook is fair to good, depending upon whether the entire tumor is removed.

Complications

The most serious complication is blindness. This can occur if the optic nerve is seriously damaged.

The tumor or its removal may cause permanent hormone imbalances. The affected hormones may need to be replaced.

Calling your health care provider

Call your health care provider if you develop any symptoms of a pituitary tumor.

References

Melmed S, Kleinberg D. Anterior pituitary. In: Kronenberg HM, Melmed S, Polonsky KS, Larsen PR. Williams Textbook of Endocrinology. 11th ed. Philadelphia, PA: Saunders Elsevier; 2008:chap 8.

See also:

• Disease

  Cancer

  Cancer is the uncontrolled growth of abnormal cells in the body. Cancerous cells are also called malignant cells.

• Disease

  Hyperthyroidism

  

  Hyperthyroidism is a condition in which the thyroid gland makes too much thyroid hormone. The condition is often referred to as an “overactive thyroid.”

• Test

  TSH test

  

  A TSH test measures the amount of thyroid stimulating hormone (TSH) in your blood. TSH is produced by the pituitary gland and tells the thyroid gland to make and release the hormones thyroxine (T4) and triiodothyronine (T3). See also:

• Special Topic

  Endocrine glands

  

  Endocrine glands release hormones into the bloodstream. Endocrine glands include the: Adrenal Islets of Langerhans in the pancreas Ovaries Parathyroid Pineal Pituitary Thyroid

• Disease

  Acromegaly

  

  Acromegaly is a metabolic disorder in which there is too much growth hormone and the body tissues gradually enlarge.

• Disease

  Hypopituitarism

  

  Hypopituitarism is a condition in which the pituitary gland does not produce normal amounts of some or all of its hormones.

• Test

  Prolactin

  Prolactin is a hormone released by the pituitary gland. The prolactin test measures the amount of prolactin in the blood.

• Disease

  Gigantism

  

  Gigantism is abnormally large growth due to an excess of during childhood, before the bone growth plates have closed.

• Disease

  Prolactinoma

  

  A prolactinoma is a noncancerous that produces a hormone called prolactin. This results in too much prolactin in the blood.

• Symptoms

  Cyst

  A cyst is a closed pocket or pouch of tissue. It can be filled with air, fluid, pus, or other material.

• Disease

  Multiple endocrine neoplasia (MEN) I

  

  Multiple endocrine neoplasia (MEN) type I is an inherited disorder in which one or more of the endocrine glands are overactive or form a tumor. Endocrine glands most commonly involved include: Pancreas Parathyroid Pituitary

• Disease

  Cushing syndrome

  

  Cushing syndrome is a disorder that occurs when your body is exposed to high levels of the hormone cortisol. It may also occur if you take too much cortisol or other steroid hormones. See also:

• Test

  ACTH

  

  An ACTH test measures ACTH, a hormone released from the anterior pituitary gland in the brain.

• Test

  Growth hormone test

  The growth hormone test measures the amount of growth hormone in the blood.

• Disease

  Craniopharyngioma

  

  A craniopharyngioma is a benign that develops near the pituitary gland (a small at the base of the brain).

Review date:

November 23, 2009

Reviewed by:

Ari S. Eckman, MD, Division of Endocrinology and Metabolism, Johns Hopkins School of Medicine, Baltimore, MD. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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