Low grade glioma
Low grade gliomas are benign (non-cancerous) tumours (grade I or II) that develop from brain cells called astrocytes.
Astrocytomas are the most common type of glioma. You will often hear the terms astrocytoma and glioma used interchangeably. Different types include; pilocytic, pilomyxoid and fibrillary astrocytomas. In children, more than 80% of astrocytomas are low grade.
Low grade astrocytomas usually develop only where they originated and grow slowly over a period of time. These tumours can arise anywhere in the brain or spinal cord. The most common areas for them to occur are the cerebral hemispheres (frontal, parietal, temporal lobes) and the cerebellum.
They can spread (disseminate) to other areas of the brain or spinal cord in the cerebrospinal fluid, although this is rare. Tumours can be solid or part cystic (fluid filled).
Who gets a low grade glioma?
This is the most common type of brain tumour in children, representing 40% of all childhood brain and spinal cord tumours. There are about 150 cases of childhood low grade gliomas a year in the UK.
Although adults also develop low grade gliomas, they behave and are treated very differently.
Like most brain tumours the cause of low grade gliomas is unknown in most cases. However, some are associated with a genetic condition called neurofibromatosis type 1.
Signs and symptoms
The symptoms depend on where the tumour is located and also whether there is increased pressure in the head (raised intracranial pressure). Symptoms include:
- nausea and vomiting (most common)
- lethargy and irritability
- seizures (fits)
- difficulty with tasks like handwriting
- gradual decline in school work
- changes in personality and behaviour
- abnormal gait (the way the child walks).
If the tumour spreads or is located in the spinal cord, the signs and symptoms may include:
- back pain
- difficulty walking
- problems with bowel and bladder control.
Tests / investigations
We will need to carry out some tests to find out as much as possible about the type, position and size of the tumour. This will help us to decide on the best treatment for your child. These tests include:
- CT scan – it is likely a CT scan of your child’s brain was the first specific test carried out at your local hospital. Although MRI scans are usually the best way of seeing the tumour and the effects of treatment, sometimes CT scans are also useful.
- MRI scan – this scan allows us to see the brain and spine in great detail and is used regularly to diagnose and follow the effect treatment is having on your child’s tumour.
Staging is a measure of how far the tumour has spread beyond its original site. It is most important to know whether the tumour has been removed by the neuro-surgeon or whether the tumour has spread to the cerebrospinal fluid and spine.