A pituitary tumor is a growth of abnormal cells in the tissues of the pituitary gland.
Pituitary tumors form in the pituitary gland, a pea-sized organ in the center of the brain, just above the back of the nose. The pituitary gland is sometimes called the "master endocrine gland" because it makes hormones that affect the way many parts of the body work. It also controls hormones made by many other glands in the body.
Anatomy of the inside of the brain, showing the pineal and pituitary glands, optic nerve, ventricles (with cerebrospinal fluid shown in blue), and other parts of the brain.
Pituitary tumors are divided into three groups:
- Benign pituitary adenomas: Tumors that are not cancer. These tumors grow very slowly and do not spread from the pituitary gland to other parts of the body.
- Invasive pituitary adenomas: Benign tumors that may spread to bones of the skull or the sinus cavity below the pituitary gland.
- Pituitary carcinomas: Tumors that are malignant (cancer). These pituitary tumors spread into other areas of the central nervous system (brain and spinal cord) or outside of the central nervous system. Very few pituitary tumors are malignant.
Pituitary tumors may be either non-functioning or functioning.
- Non-functioning pituitary tumors do not make hormones.
- Functioning pituitary tumors make more than the normal amount of one or more hormones. Most pituitary tumors are functioning tumors. The extra hormones made by pituitary tumors may cause certain signs or symptoms of disease.
The pituitary gland hormones control many other glands in the body.
Hormones made by the pituitary gland include:
- Prolactin: A hormone that causes a woman's breasts to make milk during and after pregnancy.
- Adrenocorticotropic hormone (ACTH): A hormone that causes the adrenal glands to make a hormone called cortisol. Cortisol helps control the use of sugar, protein, and fats in the body and helps the body deal with stress.
- Growth hormone: A hormone that helps control body growth and the use of sugar and fat in the body. Growth hormone is also called somatotropin.
- Thyroid-stimulating hormone: A hormone that causes the thyroid gland to make other hormones that control growth, body temperature, and heart rate. Thyroid-stimulating hormone is also called thyrotropin.
- Luteinizing hormone (LH) and follicle-stimulating hormone (FSH): Hormones that control the menstrual cycle in women and the making of sperm in men.
Having certain genetic conditions increases the risk of developing a pituitary tumor.
Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. Talk with your doctor if you think you may be at risk. Risk factors for pituitary tumors include having the following hereditary diseases:
- Multiple endocrine neoplasia type 1 (MEN1) syndrome.
- Carney complex.
- Isolated familial acromegaly.
Signs of a pituitary tumor include problems with vision and certain physical changes.
Signs and symptoms can be caused by the growth of the tumor and/or by hormones the tumor makes or by other conditions. Some tumors may not cause signs or symptoms. Check with your doctor if you have any of these problems.
Signs and symptoms of a non-functioning pituitary tumor
Sometimes, a pituitary tumor may press on or damage parts of the pituitary gland, causing it to stop making one or more hormones. Too little of a certain hormone will affect the work of the gland or organ that the hormone controls. The following signs and symptoms may occur:
- Some loss of vision.
- Loss of body hair.
- In women, less frequent or no menstrual periods or no milk from the breasts.
- In men, loss of facial hair, growth of breast tissue, and impotence.
- In women and men, lower sex drive.
- In children, slowed growth and sexual development.
Most of the tumors that make LH and FSH do not make enough extra hormone to cause signs and symptoms. These tumors are considered to be non-functioning tumors.
Signs and symptoms of a functioning pituitary tumor
When a functioning pituitary tumor makes extra hormones, the signs and symptoms will depend on the type of hormone being made.
Too much prolactin may cause:
Too much ACTH may cause:
- Some loss of vision.
- Weight gain in the face, neck, and trunk of the body, and thin arms and legs.
- A lump of fat on the back of the neck.
- Thin skin that may have purple or pink stretch marks on the chest or abdomen.
- Easy bruising.
- Growth of fine hair on the face, upper back, or arms.
- Bones that break easily.
- Anxiety, irritability, and depression.
Too much growth hormone may cause:
- Some loss of vision.
- In adults, acromegaly (growth of the bones in the face, hands, and feet). In children, the whole body may grow much taller and larger than normal.
- Tingling or numbness in the hands and fingers.
- Snoring or pauses in breathing during sleep.
- Joint pain.
- Sweating more than usual.
- Dysmorphophobia (extreme dislike of or concern about one or more parts of the body).
Too much thyroid-stimulating hormone may cause:
Other general signs and symptoms of pituitary tumors:
- Nausea and vomiting.
- Runny or "drippy" nose (cerebrospinal fluid that surrounds the brain and spinal cord leaks into the nose).
Imaging studies and tests that examine the blood and urine are used to detect (find) and diagnose a pituitary tumor.
The following tests and procedures may be used:
- Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments will also be taken.
- Eye exam : An exam to check vision and the general health of the eyes.
- Visual field exam: An exam to check a person's field of vision (the total area in which objects can be seen). This test measures both central vision (how much a person can see when looking straight ahead) and peripheral vision (how much a person can see in all other directions while staring straight ahead). The eyes are tested one at a time. The eye not being tested is covered.
- Neurological exam: A series of questions and tests to check the brain, spinal cord, and nerve function. The exam checks a person's mental status, coordination, and ability to walk normally, and how well the muscles, senses, and reflexes work. This may also be called a neuro exam or a neurologic exam.
- MRI (magnetic resonance imaging) with gadolinium: A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the brain and spinal cord. A substance called gadolinium is injected into a vein. The gadolinium collects around the cancer cells so they show up brighter in the picture. This procedure is also called nuclear magnetic resonance imaging (NMRI).
- Blood chemistry study: A procedure in which a blood sample is checked to measure the amounts of certain substances, such as glucose (sugar), released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it.
- Blood tests: Tests to measure the levels of testosterone or estrogen in the blood. A higher or lower than normal amount of these hormones may be a sign of pituitary tumor.
- Twenty-four-hour urine test: A test in which urine is collected for 24 hours to measure the amounts of certain substances. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it. A higher than normal amount of the hormone cortisol may be a sign of a pituitary tumor and Cushing syndrome.
- High-dosedexamethasone suppression test: A test in which one or more high doses of dexamethasone are given. The level of cortisol is checked from a sample of blood or from urine that is collected for three days.
- Low-dose dexamethasone suppression test: A test in which one or more small doses of dexamethasone are given. The level of cortisol is checked from a sample of blood or from urine that is collected for three days.
- Venous sampling for pituitary tumors: A procedure in which a sample of blood is taken from veins coming from the pituitary gland. The sample is checked to measure the amount of ACTH released into the blood by the gland. Venous sampling may be done if blood tests show there is a tumor making ACTH, but the pituitary gland looks normal in the imaging tests.
Biopsy : The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer.
The following tests may be done on the sample of tissue that is removed:
- Immunohistochemistry: A test that uses antibodies to check for certain antigens in a sample of tissue. The antibody is usually linked to a radioactive substance or a dye that causes the tissue to light up under a microscope. This type of test may be used to tell the difference between different types of cancer.
- Immunocytochemistry: A test that uses antibodies to check for certain antigens in a sample of cells. The antibody is usually linked to a radioactive substance or a dye that causes the cells to light up under a microscope. This type of test may be used to tell the difference between different types of cancer.
- Light and electron microscopy: A laboratory test in which cells in a sample of tissue are viewed under regular and high-powered microscopes to look for certain changes in the cells.
Certain factors affect prognosis (chance of recovery) and treatment options.
The prognosis (chance of recovery) depends on the type of tumor and whether the tumor has spread into other areas of the central nervous system (brain and spinal cord) or outside of the central nervous system to other parts of the body.
Treatment options depend on the following:
- The type and size of the tumor.
- Whether the tumor is making hormones.
- Whether the tumor is causing problems with vision or other signs or symptoms.
- Whether the tumor has spread into the brain around the pituitary gland or to other parts of the body.
- Whether the tumor has just been diagnosed or has recurred (come back).