Pituitary Tumors

What are pituitary tumors?

Pituitary tumors are abnormal growths of cells in the pituitary gland. The pituitary gland is a small pea-sized gland found at the base of the brain. It releases many different hormones that affect nearly every part of the body. The gland has 2 parts: the anterior pituitary gland and the posterior pituitary gland.

Tumors can affect the way the gland works. When the gland does not work right, it may make too much or too little of some of the hormones.

Hormones released by the anterior pituitary gland are:

• adrenocorticotropic hormone (ACTH)
• follicle-stimulating hormone (FSH)
• growth hormone (GH)
• luteinizing hormone (LH)
• prolactin (PRL)
• thyroid-stimulating hormone (TSH).

Hormones released by the posterior pituitary gland are:

• oxytocin
• antidiuretic hormone (ADH) or arginine vasopressin (AVP).

There are 2 types of pituitary tumors: secretory and nonsecretory.

• A secretory pituitary tumor may make too much hormone (hormone overproduction).
• A nonsecretory tumor interferes with the ability of the gland to make hormones, causing hormone underproduction.

How do they occur and what problems can they cause?

Pituitary tumors, also called pituitary adenomas, are caused by abnormal cell growth. The cause of the abnormal growth is not always known, but some tumors seem to happen because of a genetic mutation that may or may not have been inherited. The tumors are usually not cancerous.

As a tumor grows, it may press against the pituitary gland or other areas in the brain, causing symptoms such as headaches or vision problems.

It can cause other problems because it changes the normal balance of hormones. The changes in hormones can cause a variety of problems in the body. A tumor may affect:

• growth
• bone and muscle development
• the balance of muscle and fat tissue in the body
• the ability to have a child or to enjoy sex
• the balance of fluids in the body
• metabolism, which is the rate at which the body's cells do their work
• 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 secretory pituitary tumors?

Secretory tumors make too much of the hormones prolactin, growth hormone, or ACTH.

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 decreased testicle size.

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

• a deep, husky voice
• big hands and feet
• hirsutism, which means becoming more hairy
• enlargement of the bones 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 fatter and more rounded
• easy bruising
• mood changes.

Because Cushing's can cause type 2 diabetes, you may also have the symptoms of diabetes, including increased thirst and urination, fatigue, and blurry vision.

What are the symptoms of nonsecretory pituitary tumors?

A nonsecretory tumor interferes with the ability of the gland to make hormones. 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 height and growth rate 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.

Symptoms caused by LH and FSH deficiency include:

• in children:
  • delay or absence of puberty
• in women:
  • decreased sex drive
  • irregular menstrual periods.
• 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
• MRI.

How are they treated?

The treatment depends on the problem. Tumors may be treated with radiation therapy, drug therapy, or surgery. For example, you may be given medicine to shrink the tumor or, if you have a nonsecretory tumor, medicine to provide the hormone you are lacking. If you have acromegaly, radiation therapy may be used to help reduce the levels of growth hormone. Secretory tumors often need to be removed with surgery.

How long will the effects last?

The effects of a pituitary tumor will last as long as it remains untreated. If the tumor is a nonsecretory tumor, you will need to keep taking replacement hormone medicine.

When surgery is done to remove a tumor, a common side effect is a condition called hypopituitarism, which means not having 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 healthcare provider know if you develop 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.