About pleomorphic xanthoastrocytoma

Read about pleomorphic xanthoastrocytoma and how it is diagnosed.

What it is

A pleomorphic xanthoastrocytoma (PXA) is a very rare type of astrocytoma brain tumour. It is pronounced plee-o-morf-ick zan-thow-astro-sigh-toe-ma. These start from particular cells in the brain called astrocytes. Astrocytes are cells that support the nerve cells of the brain.

Most of these tumours are low grade or benign and are usually slow growing. Very rarely, they can change and become a more malignant type of tumour.

Pleomorphic xanthoastrocytomas 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), or in the spinal cord.

Pleomorphic xanthoastrocytomas affect males and females equally. They occur mostly in children and young people and are rare in older adults. The average age at diagnosis is 12 years. 

Causes

We don’t know the cause of pleomorphic xanthoastroctyomas.

People with these tumours appear to develop them with no obvious cause. 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.

Symptoms

Low grade pleomorphic xanthoastrocytomas usually grow very slowly. They tend to cause mild symptoms that gradually get worse over many months.

The tumour might 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
  • drowsiness

Doctors prescribe steroids, (usually dexamethasone) to control the raised pressure.

Some people have a fit (seizure) as the first sign of the tumour. Doctors will prescribe anti epileptic medicines to control the fits.

Diagnosing

Tests to diagnose pleomorphic xanthoastrocytoma might include:

  • physical examination
  • CT scan of the brain
  • MRI scan of the brain and spinal cord
  • taking a tissue sample (a biopsy)
  • electroencephalogram (EEG)

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.

Treatment

Your treatment depends on a number of factors including where the tumour is in your brain and how fit and well you are.

Last reviewed: 
04 Dec 2012
  • Cancer Principles and practice of oncology (8th edition)
    VT. De Vita, TS. Lawrence, and SA. Rosenberg
    Lippincott, Wiliams and Wilkins, 2008

  • Pleomorphic xanthoastrocytoma of the brain: MR findings in six patients
    R D Tien, C A Cardenas and S Rajagopalan
    American Journal of Roentgenology Volume 1992. 159, Issue 6

  • Pleomorphic xanthoastrocytoma: what do we really know about it?
    C. Giannini (and others)
    Cancer. 1999 May 1;85(9):2033-45

Related links