Mayo Clinic Health Library

Pituitary tumors

Updated: 11-14-2012

Definition

Pituitary tumors are abnormal growths that develop in your pituitary gland. Some pituitary tumors cause excessive production of hormones that regulate important functions of your body. Other pituitary tumors can restrict normal functions of your pituitary gland, causing it to produce lower levels of hormones.

The vast majority of pituitary tumors are noncancerous growths (adenomas). Adenomas remain confined to your pituitary gland or surrounding tissues and don't spread to other parts of your body.

Treatment for pituitary tumors involves various options, including removing the tumor, controlling its growth and managing your hormone levels with medications. Your doctor may recommend observation — or a ''wait and see'' approach.

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Symptoms

A pituitary tumor can cause your pituitary gland to produce too much or too few hormones, which can cause problems in your body. Large pituitary tumors — those measuring about 1 centimeter (slightly less than a half-inch) or larger — are known as macroadenomas. Smaller tumors are called microadenomas. Macroadenomas can put pressure on the rest of the pituitary gland and nearby structures.

Symptoms related to tumor pressure
Signs and symptoms of pressure from a pituitary tumor may include:

  • Headache
  • Vision loss, particularly loss of peripheral vision
  • Nausea and vomiting
  • Symptoms of pituitary hormone deficiency
  • Weakness
  • Less frequent or no menstrual periods
  • Body hair loss
  • Sexual dysfunction
  • Increased frequency and amount of urination
  • Unintended weight loss or gain

Symptoms related to hormone level changes
Some pituitary tumors, called functioning tumors, also produce hormones, generally causing an overproduction of hormones. Different types of functioning tumors can develop in your pituitary gland, each causing specific signs and symptoms and sometimes a combination of them.

Adrenocorticotropic hormone-secreting (ACTH) tumors
ACTH tumors produce the hormone adrenocorticotropin, which stimulates your adrenal glands to make the hormone cortisol. Cushing's syndrome results from your adrenal glands producing too much cortisol. Signs and symptoms of Cushing's syndrome may include:

  • Fat accumulation around your midsection and upper back
  • Exaggerated facial roundness
  • A characteristic hump on the upper part of your back
  • High blood pressure
  • High blood sugar
  • Muscle weakness
  • Bruising
  • Stretch marks
  • Thinning of your skin
  • Anxiety, irritability or depression

Growth hormone-secreting tumors
These tumors produce excess growth hormone. The effects from excess growth hormone (acromegaly) may include:

  • Coarsened facial features
  • Enlarged hands and feet
  • Excess sweating
  • High blood sugar
  • Heart problems
  • Joint pain
  • Misaligned teeth
  • Increased growth of body hair

Accelerated and excessive linear growth may occur in children and adolescents.

Prolactin-secreting tumors
Overproduction of prolactin from a pituitary tumor (prolactinoma) can cause a decrease in normal levels of sex hormones — estrogen in women and testosterone in men. Excessive prolactin in the blood can affect men and women differently.

In women, prolactinoma may cause:

  • Irregular menstrual periods
  • Lack of menstrual periods
  • Milky discharge from the breasts

In men, a prolactin-producing tumor may cause male hypogonadism. Signs and symptoms may include:

  • Erectile dysfunction (ED)
  • Infertility
  • Loss of sex drive

Thyroid-stimulating hormone-secreting tumors
When a pituitary tumor overproduces thyroid-stimulating hormone, your thyroid gland makes too much of the hormone thyroxine. This is a rare cause of hyperthyroidism or overactive thyroid disease. Hyperthyroidism can accelerate your body's metabolism, causing:

  • Sudden weight loss
  • Rapid or irregular heartbeat
  • Nervousness or irritability
  • Frequent bowel movements
  • Feeling warm or hot

When to see a doctor
If you develop signs and symptoms that may be associated with a pituitary tumor, see your doctor to determine if this is the cause of your symptoms. Pituitary tumors often can be treated effectively to return your hormone levels to normal and alleviate your signs and symptoms.

If you know that multiple endocrine neoplasia, type I (MEN I) runs in your family, talk to your doctor about periodic tests that may help detect a pituitary tumor early.

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Causes

The cause of uncontrolled cell growth in the pituitary gland, creating a tumor, remains unknown. The pituitary gland is a small, bean-shaped gland situated at the base of your brain, somewhat behind your nose and between your ears. Despite its small size, the gland influences nearly every part of your body. The hormones it produces help regulate important functions, such as growth, blood pressure and reproduction.

A small percentage of pituitary tumor cases runs in families, but most have no apparent hereditary factor. Still, scientists suspect that genetic alterations play an important role in how pituitary tumors develop.

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Risk factors

Although pituitary tumors can occur at any age, they're most likely to occur in older adults. People with a family history of certain hereditary conditions, such as multiple endocrine neoplasia, type I (MEN I), have an increased risk of pituitary tumors. In MEN I, multiple tumors occur in various glands of the endocrine system. Genetic testing is available for this disorder.

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Complications

Pituitary tumors usually don't grow or spread extensively. However, they can adversely affect your health, possibly causing:

  • Vision loss. A pituitary tumor can put pressure on the optic nerves, which are close to your pituitary gland, and cause loss of vision.
  • Permanent hormone deficiency. The presence of a pituitary tumor or the removal of one may permanently alter your hormone supply, which may need to be replaced with hormone medications.
  • Diabetes insipidus. This is a possible complication of a large pituitary tumor or of some treatments for pituitary tumors. Not to be confused with the more common diabetes mellitus, which involves high sugar levels in the blood and urine, diabetes insipidus is the result of the pituitary making too little vasopressin, which controls the concentration of urine in the kidneys. Diabetes insipidus causes excess amounts of urine and severe thirst, which can lead to dehydration.

A rare but potentially serious complication of a pituitary tumor is pituitary apoplexy, when sudden bleeding into the tumor occurs. Pituitary apoplexy requires emergency treatment, usually with corticosteroids and possibly surgery.

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Preparing for your appointment

You're likely to start by seeing your family doctor or a general practitioner. If your doctor finds evidence of a pituitary tumor, he or she might recommend you see specialists, such as a brain surgeon (neurosurgeon) or a doctor who specializes in treating disorders of the endocrine system (endocrinologist). Here's some information to help you prepare for your appointment.

What you can do
Finding out you have a pituitary tumor can be frightening. Through the process of getting a diagnosis, learn as much as you can about your condition, and give your doctor as much information as possible.

  • Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
  • Write down key personal information, including any major stresses or recent life changes.
  • Make a list of all medications, vitamins or supplements you're taking.
  • Take a family member or friend along, if possible. Sometimes it can be difficult to soak up all the information you get during an appointment. Someone who accompanies you may remember something that you missed or forgot.
  • Take notes or record your discussion with your doctor, or ask a friend or family member to do it.
  • Write down questions to ask your doctor.

Preparing a list of questions for your doctor will help you make the most of your time together. List your questions from most important to least important. For a pituitary tumor, some basic questions to ask your doctor include:

  • What is likely causing my symptoms or condition?
  • Other than the most likely cause, what are other possible causes for my symptoms or condition?
  • What specialists should I see?
  • What kinds of tests do I need?
  • What is the best course of action?
  • What are the alternatives to the primary approach you're suggesting?
  • I have these other health conditions. How can I best manage them together?
  • Are there any restrictions that I need to follow?
  • Are there any brochures or other printed material that I can take home with me? What websites do you recommend?

Don't hesitate to ask other questions during your appointment at any time.

What to expect from your doctor
Your doctor is likely to ask you a number of questions, including:

  • When did you begin experiencing symptoms?
  • Have your symptoms been continuous or occasional?
  • How severe are your symptoms?
  • What, if anything, seems to improve your symptoms?
  • What, if anything, appears to worsen your symptoms?
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Tests and diagnosis

Tests your doctor may conduct to diagnose a pituitary tumor include:

  • Blood and urine tests. Tests of your blood and urine samples can determine whether you have an overproduction or deficiency of hormones.
  • Brain imaging. A computerized tomography (CT) or magnetic resonance imaging (MRI) scan of your brain can help your doctor judge the location and size of a pituitary tumor.
  • Vision testing. Such tests can determine if growth of a pituitary tumor has impaired your sight or peripheral vision.

In addition, your doctor may refer you to an endocrinologist for more extensive testing.

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Treatments and drugs

Treatment for a pituitary tumor depends on the type of tumor, its size and how far it has grown into your brain. Your age and overall health also are factors. Because pituitary tumors can cause serious problems by putting pressure on your brain, treatment often is necessary. Early detection of pituitary tumors is key to successful treatment.

Treatment involves a team of medical experts, possibly including a brain surgeon (neurosurgeon), endocrine system specialist (endocrinologist) and a nervous system specialist (neurologist). Doctors generally use surgery, radiation therapy and medications, either alone or in combination, to treat a pituitary tumor and return hormone production to normal levels.

Surgery
Surgical removal of a pituitary tumor usually is necessary if the tumor is pressing on the optic nerves, which can cause loss of vision, or if the tumor is overproducing certain hormones. The success of surgery depends on the tumor type, its location, its size and whether the tumor has invaded surrounding tissues. The two main surgical techniques for treating pituitary tumors are:

  • Endoscopic transnasal transsphenoidal approach. With this approach, a doctor usually can reach and remove the tumor through your nose and sinuses without an external incision. No other part of your brain is affected, and there's no visible scar. However, very large tumors may be difficult to remove with this procedure, especially if a tumor has invaded nearby nerves or brain tissue.
  • Transcranial approach (craniotomy). During this procedure, the tumor is removed through the upper part of your skull by way of an incision in your scalp. It's easier to reach large or more complicated tumors using this procedure.

Radiation therapy
Radiation therapy uses high-energy X-rays to destroy tumors. It can be used after surgery or alone as primary treatment if surgery isn't an option. Radiation therapy can be beneficial if a tumor persists or returns after surgery and causes signs and symptoms that medications don't relieve. Methods of radiation therapy include:

  • External beam radiation. This form of radiation therapy delivers radiation in small increments over a period of time. A series of treatments, usually five times a week over a four- to six-week period, is performed on an outpatient basis. While this therapy is often effective, it may take years to fully control the tumor growth and hormone production. Radiation therapy may also damage remaining normal pituitary cells and normal brain tissue, particularly near the pituitary gland.
  • Gamma Knife stereotactic radiosurgery. This type of radiation therapy focuses radiation beams precisely on the tumor without an incision. Radiation beams that are the exact size and shape of the tumor are delivered into the tumor with the aid of special brain-imaging techniques. With Gamma Knife stereotactic radiosurgery, a minimal amount of radiation comes in contact with healthy tissue surrounding the tumor, decreasing the risk of damage to normal tissue. The benefits of this type of surgery, like those of external beam radiation, often aren't immediate and may take months or years to be fully effective. However, doctors can't use this therapy if the tumor is very close to the optic nerves or other sensitive structures.

Medications
Treatment with medications may help to block excess hormone secretion and sometimes shrink certain types of pituitary tumors:

  • Prolactin-secreting tumors (prolactinomas). The drugs bromocriptine (Parlodel, Cycloset) and cabergoline can treat these types of tumors by decreasing prolactin secretion and often reducing the size of the tumor. These drugs are often so effective in treating these types of tumors that surgery isn't necessary. Possible side effects of these drugs include drowsiness, dizziness, nausea, vomiting, diarrhea or constipation, confusion, and depression. Some people may also develop compulsive behaviors, such as gambling, while taking these medications.
  • Growth hormone-secreting tumors. Two types of drugs are available for these types of pituitary tumors and are especially useful if surgery has been unsuccessful in normalizing growth hormone production. Drugs known as somatostatin analogs (Sandostatin, Somatuline Depot, others) cause a decrease in growth hormone production and may decrease the size of the tumor. These drugs can have minor side effects, such as nausea, vomiting, diarrhea, stomach pain, dizziness, headache and pain at the site of injection, though many of these side effects improve or even go away with time. They can also cause gallstones and may worsen diabetes if you already have it. Pegvisomant (Somavert) blocks the effect of excess growth hormone on the body. This drug has few side effects, except it may cause liver damage in some people.

If a pituitary tumor has resulted in decreased hormone production, or if removal of a pituitary tumor has lowered hormone production, you may need to take replacement hormones to maintain normal hormone levels.

Watchful waiting
In watchful waiting — also known as observation, expectant therapy or deferred therapy — you may need regular follow-up tests to monitor for evidence of progression of your pituitary tumor. Watchful waiting, which involves no active medical treatment, may be an option if your tumor isn't causing any signs or symptoms.

Watchful waiting may be particularly appropriate if you're older or in poor health. Many people with pituitary tumors function normally without treatment if the tumor isn't causing other problems. If you're younger, watchful waiting also can be an option as long as you accept the possibility of your tumor changing or growing during the observation period, possibly requiring treatment. You and your doctor can weigh the risk of symptoms developing versus treatment.

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Coping and support

It's natural for you and your family to have many questions throughout the diagnosis and treatment of a pituitary tumor. The process can be overwhelming — and frightening. That's why it's important to learn as much as you can about your condition. The more you and your family know and understand about each aspect of your care, the better.

You might also find it helpful to share your feelings with others in similar situations. Check to see if support groups for people with pituitary tumors and their families are available in your area. Hospitals often sponsor these groups. Your medical team also may be able to help you find the emotional support you might need.

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