Alternative names: Adenomas.
Although pituitary tumors are classified as brain tumors they have very few similarities to other types of brain tumor. Much general information about brain tumors will not be appropriate for people with pituitary tumors, although you may still wish to read it.
The pituitary gland is a small oval-shaped gland found at the base of the brain, below the optic nerve (the nerve which leads to and from the eye). The pituitary gland produces hormones which control and regulate the other glands in the body. These glands release hormones that are responsible for the body's growth and metabolism. The pituitary gland is divided into two parts: the anterior (front) and posterior (back).
Cells within the brain normally grow in an orderly and controlled way, but if for some reason this order is disrupted, the cells continue to divide and form a lump or tumor. A tumor may be either benign or malignant. Although a benign tumor can continue to grow, the cells do not spread from the original site. In a malignant tumor, the cells can invade and destroy surrounding tissue and may spread to other parts of the brain.
Pituitary tumors are one of the most common types and make up nearly 10% of all brain tumors. They are most commonly found in young or middle-aged adults.
As with most brain tumors, the cause of pituitary tumors is unknown. Research is being carried out into possible causes.
Signs and symptoms of pituitary tumors are caused either by direct pressure from the tumor itself, or by a change in the normal hormone levels. As the tumor grows, it puts pressure on the optic nerve (which leads to the eye) and this often causes headaches and vision problems.
Symptoms caused by a change in hormone levels usually take a long time to develop.
Prolactin-secreting tumors are the most common type of secreting tumor. Women with this type of tumor may notice that their monthly periods stop and they may also produce small amounts of breast milk. Symptoms in men may include impotence (loss of the ability to have an erection).
Infertility (inability to have children) is common in both men and women and the tumor may be discovered during routine tests for infertility.
Symptoms of other secreting tumors will relate to the hormones that are released.
Growth hormone-secreting tumors: Excess production of growth hormones can cause a condition called giantism. This leads to abnormal growth that is known as acromegaly. This causes enlargement of the hands, feet, lower jaw and brows, and can also lead to high blood pressure and diabetes.
TSH-secreting tumors: A tumor that releases too much TSH causes a disruption in the body's normal metabolism. However, these tumors are extremely rare.
ACTH-secreting tumors: Over-production of ACTH can produce a number of symptoms, including Cushing's syndrome, which is characterized by a round face (known as moon-face), weight gain, increased facial hair in women, and mental changes such as depression.
Other anterior pituitary tumors: Tumors that secrete FSH or LH are very rare and are likely to cause infertility.
Posterior pituitary tumors: Tumors in the posterior pituitary are very rare and disturbances in this area are more likely to be caused by pressure being applied to the area from the surrounding tissues.
The most common symptom of a problem in the posterior pituitary is a condition called diabetes insipidus (not the same as the more common diabetes mellitus). The main symptom of diabetes insipidus is being very thirsty and passing large amounts of very weak urine.
Some problems which seem to be other diseases may in fact be a tumor. For example, a pituitary tumor can present like a subarachnoid hemorrhage, which is a kind of stroke.
Pituitary tumors are either secreting (producing hormones) or non-secreting tumors (not producing hormones). Secreting tumors can release excess amounts of any of the pituitary hormones, and are named after the hormone that is being over-produced, for example, a prolactin-secreting tumor.
Pituitary tumors are often discovered during a blood test. If high levels of pituitary hormones are found in your blood, your doctor may arrange for you to have a CT scan or MRI scan. The scans will normally be able to confirm whether a pituitary tumor is present or not.
CT (computerized tomography) scan: A CT scan takes a series of X-rays which build up a three-dimensional picture of the inside of the body. The scan is painless but takes from 10-30 minutes. CT scans use a small amount of radiation, which will be very unlikely to harm you and will not harm anyone you come into contact with. You will be asked not to eat or drink for at least four hours before the scan.
Most people who have a CT scan are given a drink or injection to allow particular areas to be seen more clearly. This may make you feel hot all over. Before having the injection or drink, it is important to tell the person doing this test if you are allergic to iodine or have asthma.
MRI (magnetic resonance imaging) scan: This test is similar to a CT scan, but uses magnetism instead of X-rays to build up a detailed picture of areas of your body. During the scan you will be asked to lie very still on the couch inside a long tube for about 30 minutes. It is painless but can be uncomfortable, and some people feel a bit claustrophobic during the scan. It is also noisy, but you will be given earplugs or headphones.
Some people are given an injection of dye into a vein in the arm, but this usually does not cause any discomfort.
Eye tests: By examining your eyes, your doctor can detect pressure on the optic nerve, which may indicate that a tumor is present. A simple test may also be done to check your visual fields (range of vision).
In order to plan treatment, it is important to find out as much as possible about the type, position and size of the tumor. This is done through a number of tests and investigations.
Your treatment will usually be planned by a team of specialists known as a multidisciplinary team (MDT). The team will usually include a doctor who operates on the brain (neurosurgeon), a doctor who specializes in treating illnesses of the brain (neurologist), a specialist nurse and possibly other health professionals, such as a physiotherapist or a dietitian.
Surgery is the most common treatment for most pituitary tumors. The aim of surgery is to remove the tumor and leave at least some of the normal pituitary gland behind. This is not always possible, and in some cases the whole gland needs to be removed.
Surgery is usually carried out by making a small cut on the inside of the roof of the nose, or by making a small opening under the upper lip, to be able to reach the pituitary gland. This makes recovery after surgery much quicker than other operations for brain tumors. Your doctor will explain the operation to you in more detail beforehand.
Drug treatment. Some prolactin-secreting tumors can be treated with a drug called bromocriptine, which reduces the production of prolactin.
If the whole pituitary gland is removed, drugs will have to be taken to replace the hormones that are normally produced (hormone replacement).
Radiotherapy treatment uses high-energy rays to destroy abnormal cells, and is an extremely effective and safe form of treatment, which is often used following pituitary surgery for all types of tumor.
Almost all tumors of the pituitary gland are benign and do not spread.
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