Pituitary Tumors

What are pituitary tumors?

Pituitary tumors are abnormal growths of cells in the pituitary gland. This gland is located at the base of the brain. It is about the size of a pea. It releases many different hormones that affect nearly every part of the body.

Pituitary tumors can be benign (noncancerous) or malignant (cancerous). Most are benign. However, even benign tumors can cause problems because they can affect the way the gland works. When the gland does not work right, it may make too much or too little hormone.

Hormones released by the pituitary gland are:

• adrenocorticotropic hormone (ACTH)
• follicle-stimulating hormone (FSH)
• growth hormone (GH)
• luteinizing hormone (LH)
• prolactin (PRL)
• thyroid-stimulating hormone (TSH)
• oxytocin
• antidiuretic hormone (ADH) or arginine vasopressin (AVP)

Pituitary tumors are also called pituitary adenomas.

How do they occur and what problems can they cause?

Pituitary tumors are caused by abnormal cell growth. The cause of the abnormal growth is not always known. Some tumors seem to happen because of a change in the genes (a mutation), which may have been inherited or may have happened after birth.

As a tumor grows, it may press against the gland or other parts of the brain. This can cause symptoms, such as headaches or vision problems. This is often why a pituitary tumor needs to be removed, even if it is not cancerous.

A tumor can cause other problems as well because it changes the normal balance of hormones. The changes in hormones can cause a number of different problems. A tumor may affect:

• growth, especially in a child
• bone and muscle development or strength
• the balance of muscle and fat tissue in the body
• the ability to enjoy sex or have a child
• the balance of fluids in the body
• metabolism, which is the rate at which the body uses calories
• blood pressure
• the heart
• the immune system, which helps the body fight infection

A pituitary tumor can also cause the breasts to make milk, even when a woman is not pregnant or has not just given birth.

What are the symptoms of pituitary tumors?

A tumor that makes too much of the hormones prolactin, growth hormone, or ACTH is called a secretory tumor. Too much prolactin in the body can cause:

• In women:
  • infertility, which is trouble getting pregnant
  • amenorrhea, which means not having menstrual periods
  • galactorrhea, which is abnormal leakage of milk from the breasts (not related to pregnancy)
• In men:
  • decreased sex drive
  • erectile dysfunction, which means trouble having or keeping an erection
  • hypogonadism, which is testicles that are smaller than normal

Too much growth hormone in adults causes a problem called acromegaly. Its symptoms in men and women may include:

• a deep, husky voice
• enlarged hands and feet
• hirsutism, which means becoming more hairy
• enlargement of the bones and features of the face

Too much ACTH causes Cushing's syndrome. Symptoms of Cushing's syndrome include:

• weight gain
• "moon face," which means a face that becomes full and more rounded
• easy bruising
• mood changes

Because Cushing's can cause high blood sugar and diabetes, you may also have the symptoms of diabetes, including increased thirst and urination, fatigue, and blurry vision.

A tumor that interferes with the ability of the gland to make hormones is called a nonsecretory tumor. It can cause underproduction of growth hormone, TSH, LH, or FSH.

Symptoms of not having enough growth hormone are:

• decreased muscle strength and ability to exercise
• slower growth rate, especially height in children
• too much weight gain, leading to obesity

It increases the risk of heart disease and high cholesterol.

Symptoms of having too little TSH include:

• tiredness
• weight gain
• lack of energy
• feeling cold all the time
• constipation
• depression

Symptoms caused by LH and FSH deficiency include:

• In children:
  • delay or absence of puberty
• In women:
  • decreased sex drive
  • irregular menstrual periods
  • trouble getting pregnant (infertility)
• In men:
  • decreased sex drive
  • smaller testicles.

How are they diagnosed?

Your healthcare provider will ask about your symptoms and give you a careful physical exam. You may have the following tests:

• blood tests
• urine tests
• X-rays
• CT scan of the brain
• MRI of the brain.

How are they treated?

The treatment depends on the type of tumor and the problems it is causing. Tumors may be treated with radiation therapy, drug therapy, or surgery. For example, you may be given medicine or radiation to shrink the tumor. You may be given replacement medicine to provide hormones you are no longer making enough of. If you have acromegaly, radiation therapy may be used to stop the gland from making too much growth hormone.

How long will the effects last?

Without treatment, the tumor will keep causing problems.

If you are taking replacement hormone medicine, you will usually need to take it the rest of your life.

If you have surgery to remove a tumor, a problem called hypopituitarism is a common side effect. It means you do not have enough pituitary hormones. When this happens, you will need to take replacement hormone medicine after the surgery.

How can I help take care of myself?

• Carefully follow your healthcare provider's instructions for taking medicine prescribed for you.
• Let your provider know if you have any new symptoms.
• Be sure to keep your follow-up appointments with your provider. It may take several weeks to find the correct doses of replacement hormones, if you need them. Once the correct dose is determined, you will need to check your hormone levels every few months.

How can I help prevent pituitary tumors?

There is no way to prevent the development of pituitary tumors.

For more information, contact:

• The Hormone Foundation
  Phone: 800-HORMONE
  Web site http://www.hormone.org.
• The Pituitary Network Association
  Phone: 805-499-9973
  Web site: http://www.pituitary.org.