Types of primary brain tumours

• A quick guide to what's on this page
• How brain tumours are sorted into different types
• Brain tumour grade - benign or malignant
• Gliomas
• Acoustic neuromas
• Astrocytomas (including glioblastoma multiforme)
• Craniopharyngiomas
• Ependymomas
• Haemangioblastomas
• Lymphomas
• Meningiomas
• Mixed gliomas
• Oligodendrogliomas
• Pineal region tumours
• Pituitary tumours
• Primitive neuroectodermal tumours (PNETs)
• Spinal cord tumours

There are nearly 100 different types of brain tumours. They are generally named after the type of cell they developed from. Most brain tumours develop from the cells that support the nerve cells of the brain. These are called glial cells. A tumour of glial cells is called a glioma.

Brain tumours can also be named after the area they are growing in. A tumour of the pituitary gland is called a pituitary adenoma. A tumour developed from the covering of the brain (the meninges) is called a meningioma. Tumours growing from the nerves entering the brain are called neuromas. An acoustic neuroma is a tumour growing on the nerve that controls hearing.

Brain tumours are put into groups according to how fast they are likely to grow. There are 4 groups called grades 1 - 4. The cells are examined under a microscope. The more normal they look, the more slowly the brain tumour is likely to develop and the lower the grade. The more abnormal the cells look, the more quickly the brain tumour is likely to grow and the higher the grade. Low grade gliomas (grade 1 and grade 2) are the slowest growing brain tumours.

You may have been told you have a benign tumour or a malignant tumour. As a rule of thumb, low grade tumours are regarded as benign and high grade as malignant. By benign, we generally mean

• The tumour is relatively slow growing
• It is less likely to come back if it is completely removed
• It is not likely to spread to other parts of the brain or spinal cord
• It may just need surgery and not radiotherapy or chemotherapy as well

By malignant, we generally mean

• The tumour is relatively fast growing
• It is likely to come back after surgery, even if completely removed
• It may spread to other parts of the brain or spinal cord
• It cannot just be treated with surgery and will need radiotherapy or chemotherapy to try to stop it from coming back

With other types of cancer, these black and white explanations of benign and malignant work well. But with brain tumours, there are a lot of grey areas. Some low grade astrocytomas can spread to other parts of the brain or spinal cord. Radiotherapy and chemotherapy are sometimes used to treat 'benign' tumours. Even a slow growing tumour can cause serious symptoms and be life threatening if in a crucial part of the brain. So, you really need to ask your specialist to explain your own situation to you fully and simply.

About half of all primary brain tumours are gliomas. There are 3 main types of glioma - astrocytoma, ependymoma and oligodendroglioma. Grade 4 astrocytoma is also called glioblastoma multiforme or GBM. A fourth type, mixed glioma, is a mixture of the other types. Your doctor will use the grade of your glioma to decide your treatment and the likely outcome. But the position of the tumour is also very important. Brain stem gliomas are particularly difficult to treat, whatever their grade. The brain stem is such a complicated and delicate part of the brain that completely removing the tumour is not likely to be possible. Unfortunately, high doses of radiotherapy are not recommended either as this may cause too much damage to the normal brain stem.

These tumours grow in the nerve that runs from the ears to the brain and controls hearing and balance. They are nearly always slow growing, do not spread and are thought of as benign brain tumours. Often, they have been there a long time by the time they are diagnosed. They are found most often in older people. Loss of hearing in one ear can be a sign of acoustic neuroma. Rarely, they are associated with one form of a genetic condition called neurofibromatosis type 2 (NF 2). In these cases, they are usually diagnosed at a much younger age, can be on both sides (bilateral) and those affected may also develop meningiomas.

This is the commonest type of glioma in both adults and children. Astrocytomas develop from cells called astrocytes. The astrocytes are the 'bricks and mortar' of the brain that support the nerve cells (neurones). They probably do other things too (but we don't know what as yet). Astrocytomas can be slow or fast growing. Some are very localised ('focal'). This means it is easy to see the border between tumour and normal brain tissue on a scan or during an operation. Focal astrocytomas are more often diagnosed in children and are not common in adults. Other astrocytomas are called 'diffuse'. These do not have a clear boundary between the tumour and normal brain tissue.

Anaplastic astrocytoma (also called grade 3 astrocytoma) and glioblastoma multiforme (GBM or grade 4 astrocytoma) are the commonest brain tumours in adults. These are malignant brain gliomas. They can sometimes spread to other parts of the brain.

These are tumours that tend to grow near the base of the brain, just above the pituitary gland. They are most often diagnosed in children, teenagers and young adults. They do not usually spread, but are near important structures in the brain and can cause problems as they grow. They can cause problems with vision and altered hormone balance. Children with craniopharyngioma can have weight gain and growth problems.

About 1 in 20 brain tumours (5%) is an ependymoma. These develop from cells called ependymal cells. These cells line the fluid-filled areas of the brain (the ventricles) and spinal cord. Their job is to repair any damaged nerve tissue. Most ependymomas are diagnosed in children or young adults. They can be high or low grade, but the cells' appearance under a microscope does not always fit with their behaviour. So the grade may not tell you much. Sometimes ependymomas can spread within the central nervous system, via the fluid that circulates round the brain and spinal cord, but this is not common.

Only 2 out of every 100 brain tumours (2%) are this type. These tumours grow from blood vessel cells. They are very slow growing and do not spread. But they can grow in the brain stem and then they are very difficult to treat. Sometimes these brain tumours can be part of a medical syndrome called von Hippel Lindau syndrome (vHL), which runs in families. People with vHL who develop haemangioblastoma may have more than one. Not everyone with vHL will get haemangioblastomas - the condition behaves differently in different people.

Sometimes lymphoma can start in the brain. This is called primary cerebral lymphoma. They are more likely to be diagnosed in people with poor immunity either because they have had an organ transplant or because they have AIDS.

Lymphoma is a cancer of the lymphatic system. These are treated differently to other types of brain tumour. There is a section on non hodgkins lymphomas in CancerHelp UK, including treatment information.

About 1 in 4 brain tumours in adults (25%) is a meningioma. They are more common in older people and in women. These are tumours growing in the tissues covering the brain. They are most often found in the forebrain or hindbrain. They are usually benign (not cancerous).

Some meningiomas are 'atypical'. This means that they behave more aggressively than normally expected for meningiomas. They can grow into surrounding brain tissue and may come back after they have been removed.

Meningioma symptoms vary a lot, depending on where in the brain they are growing.

These are gliomas that are a mixture of 2 or even 3 of the different types of glioma. The cell types can be different grades too. Your doctor will look at the different types of glioma cells and give you the treatment that is appropriate for the most aggressive cell type in your brain tumour.

About 1 in 20 brain tumours (5%) is an oligodendroglioma. These develop from cells called oligodendrocytes. These cells make a white fatty substance that covers nerves, called myelin. It helps the nerve signals (impulses) to travel along the nerves more quickly. Oligodendrogliomas are most often found in the forebrain, in the temporal or frontal lobes. They can be fast or slow growing. They are most likely to be diagnosed in adults, although they do occur in young children. Sometimes this tumour can spread within the central nervous system, in the fluid that circulates round the brain and spinal cord.

The pineal gland is in the middle of the brain, just behind the top of the brain stem. It makes the hormone melatonin. These tumours are rare. Only 1 in every 100 brain tumours (1%) are pineal tumours. Several different types of tumours can grow in the pineal region, including gliomas. The commonest types are called germ cell tumours. Germ cell tumours sometimes produce chemicals that can be tested for in the blood. These 'markers' are the same as looked for in testicular cancers - AFP and HCG. Sometimes these chemical producing germ cell tumours can be diagnosed with a blood test. They are often picked up when they are still small, because they can block the circulation of fluid around the brain and cause symptoms early on.

About 1 in 10 brain tumours (10%) are in the pituitary gland. They are more common in older people. The pituitary gland is attached to the underside of the brain. It lies in a small hollow in the skull, just behind the eyes. It controls many body functions by making and releasing chemical 'messengers' (hormones) into the bloodstream. The pituitary hormones travel in the blood to other glands in the body, such as the thyroid, ovaries and testicles. The pituitary hormones control amounts of other hormones that these glands release into the blood.

Most pituitary tumours are tumours of gland tissue and are called adenomas. They are nearly always benign - they grow slowly and do not spread. Pituitary tumours can often cause quite odd symptoms because the tumour cells make too much of one of the pituitary hormones.

These tumours develop from cells that are left over from the earliest development of the body in the womb. Normally, these cells are harmless. But sometimes they can become cancerous. Medulloblastoma is the commonest type of PNET. These grow in the hindbrain (the cerebellum). They are the most common brain tumour in children, but are also diagnosed in young adults. These tumours can be fast growing and can spread to other parts of the brain and to the spinal cord through the cerebrospinal fluid (CSF).

Up to 1 in 5 central nervous system tumours (20%) are in the spine. There are a few different types of spinal tumour. The success of treatment depends on the type of spinal tumour.

Meningiomas and neurofibromas are the commonest types seen in adults. They grow outside the spinal cord, but press on it. Astrocytomas and ependymomas, grow in the spinal cord tissue itself. These are the commonest types in children. Another rare type is called a chordoma.

Tumours growing in the bones of the spine can press on the spinal cord and cause symptoms. In adults, these are usually secondary cancers that have spread from somewhere else in the body. This is the most likely cause of a spinal tumour if you have had a cancer that has started somewhere else, for example, the lungs, the prostate, the kidney or the breast. Lymphomas and myeloma can also spread to the spine.