This page tells you about pleomorphic xanthroastrocytoma. There is information about
- What pleomorphic xanthroastrocytoma is
- Causes of pleomorphic xanthroastrocytoma
- Symptoms of pleomorphic xanthroastrocytoma
- Diagnosing pleomorphic xanthroastrocytoma
- Treating pleomorphic xanthroastrocytoma
A pleomorphic xanthroastrocytoma (PXA) is a very rare type of astrocytoma brain tumour. It is pronounced plee-o-morf-ick zan-throw-astro-sigh-toe-ma. Most are low grade but some are high grade (anaplastic PXA).
These tumours are usually benign (non cancerous) and start from particular cells in the brain called astrocytes. Astrocytes are cells that support the nerve cells of the brain.
Pleomorphic xanthroastrocytomas affect males and females equally. They tend to occur mostly in children and young people and are rare in older adults. The average age at diagnosis is 12 years. Very rarely, these tumours change and become a more malignant type of tumour.
Pleomorphic xanthroastrocytomas generally start in the upper areas of the brain called the cerebral hemispheres. Rarely, they may start in one of the membranes that surround the brain (the leptomeninges). Very rarely, these tumours start in the spinal cord.
We don’t know the cause of pleomorphic xanthoastroctyomas. People with these tumours appear to develop them with no obvious cause and medical research has not found any genetic changes likely to lead to their development. Researchers are carrying out studies to try to find the causes.
Low grade pleomorphic xanthroastrocytomas usually grow very slowly. They tend to cause mild symptoms that gradually get worse over many months. But some people have a fit (seizure) as the first sign of the tumour. Doctors will prescribe anti epileptic medicines to control the fits.
The tumour may cause increased pressure in the head. As the skull is made of bone, there is a fixed amount of space for the brain to take up. The growing tumour increases the pressure inside this fixed space (raised intracranial pressure). The raised pressure causes headaches, sickness, and drowsiness. Doctors prescribe steroids, (usually dexamethasone) to control the raised pressure.
Tests to diagnose pleomorphic xanthroastrocytoma may include
- Physical examination
- CT scan of the brain
- MRI scan of the brain and spinal cord
- Electroencephalogram (EEG)
- Taking a tissue sample (a biopsy)
An EEG records the brain's electrical activity using electrodes attached to the scalp. It can help to identify an area of the brain that is causing fits.
Your doctor (or your child’s doctor) and their specialist medical team will decide on the treatment you need, based on
- Your age, overall health, and medical history
- The type, site, and size of the tumour
- Whether the tumour has spread into nearby tissues
- How well you are likely to cope with procedures and treatments
- How your doctors expect the tumour to develop
- Your opinion and wishes
The treatment may include surgery or radiotherapy, or both. Pleomorphic xanthroastrocytomas have a high chance of cure, with long term survival rates of between 8 and 9 out of 10 (80 to 90%). The chance of cure is best if surgeons can remove the whole tumour.
Anaplastic PXA (high grade) are more difficult to treat and usually the neuro-oncology team recommend radiotherapy after your surgery.
The main treatment is to remove as much of the tumour as possible. If you have your tumour completely removed, you may not need any further treatment. But you will have regular MRI scans to check whether the tumour has come back. Removing the tumour usually gets rid of any symptoms.
If a tumour cannot be completely removed and then starts to grow, or if it comes back after removal, the usual treatment is further surgery. The aim is to try to remove as much of the tumour as possible.
Radiotherapy uses high energy rays (radiation) to damage or kill cancer cells and shrink tumours. Doctors sometimes recommend radiotherapy after surgery if the tumour cannot be completely removed. But it is not clear how helpful this is, so we need more research. If surgery is not possible, your doctor may recommend radiotherapy alone to try to shrink the tumour and control it for a time.
After treatment for pleomorphic xanthroastrocytoma, you may have short term side effects. If you have raised pressure in the head during or after surgery, your doctors will prescribe dexamethasone. The dose is usually gradually reduced over a few weeks. If the surgery causes fits (seizures), your doctors will prescribe anti epileptic medicines.
The area of the surgery will affect the possible long term side effects you may have. Your surgeon will discuss any possible side effects fully with you before the operation.
If pleomorphic xanthroastrocytoma comes back, the usual treatment is to operate to remove as much of the tumour as possible. But some experimental treatments are being researched in clinical trials. lf your surgeon cannot remove the tumour because of its position, your doctors may recommend radiotherapy to help control it.
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