Types and grades of primary brain tumours

Your doctor may test a sample of the tumour to find out:

  • the grade
  • the type
  • if it has cell changes called biomarkers.

This gives your doctor information about how the tumour may develop and helps them to plan your treatment.

The grade of the tumour affects how slowly or quickly it may grow. Grade 1 and 2 (low-grade) tumours grow slowly. Grade 3 and 4 (high-grade) tumours grow more quickly.

There are many different types of primary brain tumour. These are often named after the cell or the part of the brain they start in. Different tumour types may affect different areas of the brain. Some types are usually high-grade and others are low-grade.

The most common types are called glioma (astrocytoma, oligodendroglioma or ependymoma) and meningioma. Rarer types include acoustic neuroma, lymphoma, haemangioblastoma, medulloblastoma, craniopharyngioma and tumours of the pineal gland, pituitary gland or spinal cord.

Some brain tumour types are tested to check for cell changes called biomarkers. Biomarkers may tell your doctor which treatment is most likely to be effective and how the tumour may develop.

Brain tumour types and grades

If you have had a biopsy or surgery to remove a brain tumour, samples of the tumour can be tested to find out more. Tests are done to find out the type and grade of the tumour. Some types of tumour are also tested for changes in the tumour cells called biomarkers.

These tests give your doctor information about how the tumour may develop and grow. Knowing this helps them to plan the best treatment for you.


Types of brain tumour

There are many different types of brain tumour. We can’t list all of them here.

Brain tumours are often named after the cell they develop from or the part of the brain they start in.

Gliomas

More than half of all primary brain tumours are gliomas. These tumours develop from the supporting cells (glial cells) in the brain or spinal cord. Different types of glioma are named after the different types of glial cell.

Astrocytoma is the most common glioma. It develops from star-shaped glial cells called astrocytes. Astrocytomas can be grade 1 to 4. Glioblastoma multiforme (GBM) is a type of grade 4 astrocytoma.

Oligodendroglioma develops from a type of glial cell called an oligodendrocyte. These cells make up the fatty covering of nerve cells. There are two main grades of these tumours – grade 2 and grade 3.

Ependymoma develops from a type of glial cell called ependymal cells. These cells line the fluid-filled spaces in the brain (ventricles) and the centre of the spinal cord. Ependymomas can be grade 1 to 3. They are usually low-grade, slow-growing tumours.

Meningioma

Nearly a quarter (25%) of all primary brain tumours are meningiomas. These tumours start in the tissues that cover and protect the brain and spinal cord (the meninges). Meningiomas can be grade 1 to 3. They are usually low-grade, slow-growing tumours but a small number are faster growing.

Acoustic neuroma

These tumours (also called vestibular schwannomas) usually grow slowly. They develop from the cranial nerve that connects the inner ear to the brain, called the acoustic nerve. People with a genetic condition called Neurofibromatosis type 2 (NF2) have a higher risk of developing this type of tumour.

Primary central nervous system lymphoma (PCNSL)

A lymphoma is a cancer of the lymphatic system which is part of the body’s immune system and helps fight infection. Lymphomas that start in the brain or spinal cord are called primary central nervous system lymphomas (PCNSL). They are rare and usually grow quickly.

You may have slightly different tests and treatment for PCNSL. 

Haemangioblastoma

Haemangioblastoma is a rare, slow-growing tumour that usually affects the cerebellum and sometimes the brain stem or spinal cord. It develops from the cells lining the blood vessels in the brain.

Medulloblastoma

Medulloblastoma is a high-grade tumour that develops in the cerebellum. This tumour is rare in adults but is one of the most common brain tumours in children.

Pineal region tumours

These rare tumours affect the pineal gland in the centre of the brain. There are different types of pineal region tumours. The most common one is a germ cell tumour.

Pituitary gland tumours

The most common tumours of the pituitary gland are adenomas. They are slow-growing tumours that can affect how the pituitary gland produces hormones.

Craniopharyngioma

These tumours affect an area above the pituitary gland and near the cranial nerve from the eyes to the brain. They are rare and usually slow-growing. They can affect how the pituitary gland produces hormones and cause problems with eyesight.

Spinal cord tumours

Several types of tumour can start in the spinal cord but this is rare. These tumours usually cause problems by pressing on the nerves of the spinal cord.

You may have slightly different tests and treatment for a tumour in the spinal cord. 


Biomarkers

Some types of brain tumour are tested to check for changes in the tumour cells. These changes are called biomarkers or biological markers. Your doctor may also call them molecular markers. Knowing about biomarkers may tell your doctor which treatment is most likely to be effective and how the tumour may develop.

There are tests for different types of biomarkers. Some tests look for changes in different genes of the tumour cells. For gliomas, this includes changes in genes called:

  • IDH
  • 1p/19q.

Another test checks the levels of a protein called MGMT in the glioma tumour cells.

For medulloblastoma, tests are done to look for changes called:

  • WNT
  • SHH.

Your doctor can tell you more about this and if biomarker tests are helpful in your situation.

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