Categorizing brain tumours

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A step-by-step introduction to the different types of childhood brain tumors. Answers from Canadian Paediatric Hospitals.

Key points

  • A primary brain tumour develops directly in the brain while a secondary tumour develops elsewhere in the body and spread to the brain.
  • A benign tumour is not cancerous and grows slowly.
  • A malignant tumour is cancerous, grows quickly, and can spread to other parts of the body.

There are more than 100 different types of brain tumours. Tumours are usually named after the type of cell they develop from. One example is a glioma, which grows out of glial cells. Tumours may also be described based on their location, such as a brainstem glioma. Sometimes the same tumour may have different names, which can be confusing. The name of a tumour can change as researchers learn more details about tumour cells.

There are more than 100 different types of brain tumours. Tumours are usually named after the type of cell they develop from. One example is a glioma, which grows out of glial cells. Tumours may also be described based on their location, such as a brainstem glioma. Sometimes the same tumour may have different names, which can be confusing. The name of a tumour can change as researchers learn more details about tumour cells.

You may also hear tumours being described in two other general ways:

  1. Where they begin to grow: primary and secondary tumours
  2. How fast they are growing: benign and malignant brain tumours. This may also be described as the grade of a tumour.

Primary and secondary brain tumours

A primary brain tumour develops directly in the brain. Most brain tumours in children are primary brain tumours.

A secondary tumour is rare in children. It develops first somewhere else in the body, such as in the bones or skin. When these abnormal bone or skin cells spread to the brain, they are called a "secondary" tumour.

Benign and malignant brain tumours

A benign brain tumour is not cancerous. The cells in the tumour are growing slowly. Many benign brain tumours can be removed by surgery and they do not grow back. However, some benign brain tumours can be dangerous. This is because they are located in a part of the brain that is difficult to reach by surgery or in an important part of the brain that could be harmed by surgery.

A malignant brain tumour is considered a cancer. This means the abnormal cells in the tumour are making copies of themselves quickly. As a result, the tumour grows quickly, and tumour cells can spread to other parts of the brain or spine. This is called metastasis. However, in many cases, cancerous tumours can be treated with good success. They rarely spread outside the central nervous system (CNS).

Sometimes the distinction between benign and malignant is more complex. Some benign tumours can spread to other parts of the brain or spine. This may occur, for example, in the case of low grade gliomas. This does not mean that the tumour has become malignant. The low grade glioma that has spread can often be successfully treated with chemotherapy.

Sometimes a benign tumour can transform into a malignant tumour. Although more common in adults, this can happen in children, especially teenagers.

Last updated: August 14th 2009