What is a prolactinoma?

  • A prolactinoma is a tumor (lump) in your pituitary gland that occurs more commonly in women than men. The pituitary gland is an almond-shaped organ found under the middle part of your brain. Your pituitary gland makes and releases hormones such as prolactin. Hormones are special chemicals that flow through your blood to control functions of your organs and tissues. An area of your brain called the hypothalamus is found above your pituitary gland. It gives signals to your pituitary gland telling it which hormones to release, and how much. A chemical called dopamine flows from your hypothalamus to your pituitary gland. Dopamine can control how much prolactin your pituitary gland makes.

  • Prolactin normally increases to get females ready for pregnancy. It also helps the breasts of females make milk for breast-feeding. A prolactinoma may increase the amount of prolactin in your body. Too much prolactin in women can make it hard to get pregnant or have a baby. The tumor can also grow and damage nearby brain tissue, blood vessels, and nerves. Having your tumor treated may help decrease your symptoms and stop damage to your brain tissues.

What causes a prolactinoma?

A prolactinoma is caused by an abnormal growth of pituitary cells. Cells that make prolactin may change and make more abnormal cells. These abnormal cells group together and make a tumor. The tumor may change how the pituitary gland works. You may have abnormal genes that caused the tumor to grow. Genes are little pieces of information that tell your body what to do or make. The cause of your tumor may also be unknown.

What are the signs and symptoms of a prolactinoma?

Your tumor may grow and push on nearby brain tissue, blood vessels, and nerves. It may also change the amount of hormones made by your pituitary gland. When this happens, you may have any of the following:

  • Decreased desire (need) for sex.

  • Feeling very tired or sleepy most of the time.

  • Headaches, blurry vision, or trouble seeing from the corner of your eyes.

  • Infertility (unable to get your partner pregnant) or erection problems in males.

  • Irregular or absent menses (monthly period), and trouble getting pregnant or having babies for females.

  • Milk coming out of your breasts even if you are not pregnant or breast-feeding.

  • Problems thinking, remembering things, or moving some parts of your body.

How is a prolactinoma diagnosed?

Your caregiver will ask about any medical problems you have had. He may also ask about your family's health history. He will ask what symptoms you have and how bad they get. He may do a physical exam to check your health. You may need any of the following:

  • Blood tests: You may need blood taken for tests. These can tell your caregivers how much prolactin you have in your body. These tests can also show how much of the different hormones you have in your body. Blood tests may also give your caregivers information about your health. The blood can be taken from a blood vessel in your hand, arm, or the bend in your elbow. You may need to have blood drawn more than once.

  • Computed tomography scan: This is also called a CT scan. A special x-ray machine with a computer takes pictures of your brain. It can show your tumor, brain tissue, and blood vessels.

  • Magnetic resonance imaging: This is also called a MRI. The MRI shows pictures of the inside of your head. This can show your caregiver any tumors or problems inside. You will need to lay still and relax during a MRI. Never enter the MRI room with an oxygen tank, watch, or any other metal objects. This can cause serious injury.

  • Pregnancy test: Prolactin normally increases during pregnancy. This test helps caregivers find out if you are pregnant. It will tell caregivers if your pregnancy is causing you to have too much prolactin.

  • Visual field test: This test will check your visual field. Your visual field tells how wide your eyes can see. A large tumor usually decreases how much you see from the corners of your eyes. Ask your caregiver for more information about this test.

How is a prolactinoma treated?

You may need one or more of the following:

  • Dopamine agonists: These medicines increase your dopamine level. Increased amounts of dopamine can bring your prolactin level back to normal. Ask your caregiver for more information on these medicines.

  • Radiation therapy or radiosurgery: These treatments use x-rays or gamma rays to treat your tumor. Radiation may stop the tumor cells from growing, and shrink the tumor. Ask your caregiver for more information about radiation therapy and radiosurgery.

  • Surgery: This is done to remove or decrease the size of your tumor. Ask your caregiver for more information on surgeries to treat your tumor.

When should I call my caregiver?

Call your caregiver if:

  • You have trouble getting or keeping an erection.

  • Your menstrual period stops or becomes irregular.

  • Your symptoms do not go away, even with medicines.

  • You have questions about your condition, treatment, or care.

When should I seek immediate help?

Seek care immediately or call 911 if:

  • You have a very bad headache and a stiff, painful neck.

  • You suddenly have trouble seeing or a hard time moving your eyes from side to side.

  • You suddenly have trouble thinking, remembering things, or moving parts of your body.

  • You have a seizure (convulsion), or you faint.

Where can I find more information?

Contact any of the following for more information:

  • Endocrine and Metabolic Diseases Information Service
    National Institutes of Health
    6 Information Way
    Bethesda , MD 20892-3569
    Phone: 1- 888 - 828-0904
    Web Address:
  • National Institute of Neurological Disorders and Stroke
    P.O. Box 5801
    Bethesda , MD 20824
    Phone: 1- 301 - 496-5751
    Phone: 1- 800 - 352-9424
    Web Address:

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your caregivers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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