Diffuse Astrocytoma / Fibrillary Astrocytoma


Tumour Group: Gliomas
WHO Grade: Grade II
Prevalence/Incidence: Diffuse astrocytomas represent 10-15% of all astrocytic brain tumours, with an incidence of approximately 1.4 new cases per 1 million population per year
Typical Age Range: The peak incidence is in young adults between the ages of 30 and 40 (25% of all cases). Diffuse astrocytomas are uncommon in children. The mean age of occurrence is 34 years.

Description of Tumour
Treatment / Standard of Care

Description of Tumour

As the name implies, the borders of a diffuse astrocytoma tend to infiltrate into surrounding normal brain tissue. This tumour is also called low-grade or astrocytoma grade II, and is more common in men than women.

This type of tumour tends to contain microcysts and mucous-like fluid. They are grouped by the appearance and behaviour of the cells for which they are named. Brain tumour experts agree that while diffuse astrocytomas are usually slow growing, they should not be considered "benign" or "non-malignant."

Grade II astrocytomas make up about 25% of all gliomas. They may be found anywhere in the brain, but are most common in the cerebral hemispheres – the “thinking” part of the brain.


Common symptoms include, but are not limited to:

  • Changes in sensation
  • Changes in vision
  • Headaches are often the earliest signs of this tumour
  • Seizures (common presenting manifestation of the tumour)
  • Speech difficulties
  • Weakness on one side of the body (hemiparesis) is common

Treatment / Standard of Care

Treatment options depends on the overall health of the person, the type, size, and location of the tumour, if and how far it has spread and previous treatment received. The molecular profile may also guide treatment decisions.

Options may include radiation, chemotherapy, or even careful observation.


A prognosis is an estimate of the likely progress of a disease after a diagnosis, based on an average patient group. Since every person is different, please take time to talk with your health care team about how this information applies to you.

By clicking on 'Expand,' a statistic on the prognosis for diffuse astrocytomas will be shown.

Expand for Prognosis Information

For brain tumour patients, a prognosis depends on several factors, which can include age and other health issues, the size of the tumour, its molecular profile, the type of tumour, how much can be removed and its response to treatments such as chemotherapy and radiation therapy.

In adults, a diffuse astrocytoma almost always transforms into a higher grade tumour.


Adult Brain Tumour Handbook 6th Edition. Brain Tumour Foundation of Canada. 2012.

Butler, Catherine. "Low Grade Astrocytomas." Abta.org. The American Brain Tumour Association, 23 July 2012. Web. 7 May 2013.

Kleihues, P., and W. K. Cavenee. Pathology and Genetics of Tumours of the Nervous System. Lyon: IARC, 2000. Print.

Louis, David N. WHO Classification of Tumours of the Central Nervous System. Lyon: International Agency for Research on Cancer, 2007. Print

Pediatric Brain Tumour Handbook 6th Edition. Brain Tumour Foundation of Canada. 2012.

Image credited to The Armed Forces Institute of Pathology (AFIP) [Public domain], via Wikimedia Commons


You can also download this information as a Information Sheet on Diffuse Astrocytoma/Filbrillary Astrocytomas (pdf).


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