This information is about tumours of the pituitary gland. Although pituitary tumours are classified as brain tumours they have very few similarities to other types of brain tumour.
Much of our general information about brain tumours will not be appropriate for people with pituitary tumours, although you may still wish to read it.
The pituitary gland
The pituitary gland is a small oval-shaped gland found at the base of the brain (see diagram below), 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).
The anterior pituitary produces six hormones:
growth hormone which controls growth
prolactin which stimulates the production of breast milk after childbirth
ACTH (adrenocorticotrophic hormone) which stimulates the production of hormones from the adrenal glands
TSH (thyroid-stimulating hormone) which stimulates the production of hormones from the thyroid gland
FSH (follicle-stimulating hormone) and LH (leuteinising hormone) which stimulate the ovaries in women and the testes in men.
The posterior pituitary produces:
ADH (anti-diuretic hormone) which reduces the amount of urine produced by the kidneys
oxytocin which stimulates the contraction of the womb during childbirth and the production of milk for breastfeeding.
Side view of the head
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 tumour.
A tumour may be either benign or malignant. Although a benign tumour can continue to grow, the cells do not spread from the original site. In a malignant tumour, the cells can invade and destroy surrounding tissue and may spread to other parts of the brain.
Tumours affecting the whole of the central nervous system (CNS), which is made up of the brain and spinal cord, are fairly rare.
About 4500 new brain tumours are diagnosed each year in the UK. Pituitary tumours are one of the most common types and make up nearly one in 10 (10%) of all brain tumours. They are most commonly found in young or middle-aged adults.
Almost all tumours of the pituitary gland are benign and do not spread. They are sometimes called adenomas.
Pituitary tumours are either secreting (producing hormones) or non-secreting tumours (not producing hormones). Secreting tumours 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 tumour.
Causes of a pituitary tumour
As with most brain tumours, the cause of pituitary tumours is unknown. Research is being carried out into possible causes.
Signs and symptoms
Signs and symptoms of pituitary tumours are caused either by direct pressure from the tumour itself, or by a change in the normal hormone levels. As the tumour grows, it puts pressure on the optic nerve (which leads to the eye) and this often causes headaches and sight problems.
Symptoms caused by a change in hormone levels usually take a long time to develop.
Prolactin-secreting tumours are the most common type of secreting tumour. Women with this type of tumour 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 tumour may be discovered during routine tests for infertility.
Symptoms of other secreting tumours will relate to the hormones that are released.
Growth hormone-secreting tumours 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 tumours A tumour that releases too much TSH causes a disruption in the body’s normal metabolism. However, these tumours are extremely rare.
ACTH-secreting tumours Over-production of ACTH can produce a number of symptoms, including Cushing’s syndrome, which is characterised by a round face (known as moon-face), weight gain, increased facial hair in women, and mental changes such as depression.
Other anterior pituitary tumours Tumours that secrete FSH or LH are very rare and are likely to cause infertility.
Posterior pituitary tumours Tumours 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.
Tests and investigations
In order to plan your treatment, it is important to find out as much as possible about the type, position and size of the tumour. This is done through a number of tests and investigations.
Pituitary tumours 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 tumour is present or not.
CT (computerised 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 tumour is present. A simple test may also be done to check your visual fields (range of vision).
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 specialises in treating illnesses of the brain (neurologist), a specialist nurse and possibly other health professionals, such as a physiotherapist or a dietitian.
Before you have any treatment, your doctor will give you full information about what the treatment involves and explain the aims of the treatment to you. They will usually ask you to sign a form saying that you give your permission (consent) for the hospital staff to give you the treatment. No medical treatment can be given without your consent.
Benefits and disadvantages of treatment
Treatment can be given for different reasons and the potential benefits will vary depending upon the individual situation. If you have been offered treatment that aims to cure your cancer, deciding whether to have the treatment may not be difficult. However, if a cure is not possible and the treatment is to control the cancer for a period of time, it may be more difficult to decide whether to go ahead.
If you feel that you can’t make a decision about the treatment when it is first explained to you, you can always ask for more time to decide.
You are free to choose not to have the treatment and the staff can explain what may happen if you do not have it. You don’t have to give a reason for not wanting to have treatment, but it can be helpful to let the staff know your concerns so that they can give you the best advice.
Surgery is the most common treatment for most pituitary tumours. The aim of surgery is to remove the tumour 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 tumours. Your doctor will explain the operation to you in more detail beforehand.
Some prolactin-secreting tumours 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 tumour.
Treatment of pituitary tumours is usually very successful, although many people will have to continue taking hormone replacements, sometimes for the rest of their lives. Regular check-ups at an endocrinology clinic, where your hormone levels will be monitored, are likely and may continue for several years.
You may find the idea of a tumour affecting your brain extremely frightening. The brain controls the body, and not being in control is something that can be very worrying. You may experience many different emotions, including anxiety and fear. These are all normal reactions, and are part of the process many people go through in trying to come to terms with their condition.
Many people find it helpful to talk things over with their doctor or nurse, or with one of our support service nurses. Close friends and family members can also offer support.
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