What Is An Astrocytoma And How Is It Diagnosed?

An astrocytoma is a type of brain tumour that develops from astrocytes, star-shaped cells that support and protect nerve cells in the brain and spinal cord. Astrocytomas are part of a wider group of tumours known as gliomas.

An astrocytoma diagnosis can be complex because these tumours vary considerably in their characteristics, location and behaviour. Modern diagnosis therefore involves more than identifying a mass on a brain scan.

Specialists combine imaging, tissue analysis and molecular testing to build a detailed picture of the tumour and help determine the most appropriate treatment approach.

What causes an astrocytoma?

In many cases, there is no clear reason why an astrocytoma develops. Astrocytes can acquire changes in their genetic material that cause cells to grow and divide abnormally.

Some genetic and molecular changes are associated with particular types of astrocytoma. This is why molecular testing has become an important part of modern brain tumour diagnosis.

It is also important to understand that astrocytomas are not all the same. Their characteristics can vary depending on the specific genetic and molecular features identified by specialists.

What are the symptoms of an astrocytoma?

Symptoms depend largely on where the tumour is located, its size and how it affects surrounding areas of the brain.

Possible symptoms can include:

• Persistent or changing headaches
• Seizures
• Problems with memory, concentration or thinking
• Changes in speech or understanding language
• Weakness or altered sensation affecting part of the body
• Problems with balance or coordination
• Changes in vision

These symptoms can have many possible causes and do not necessarily indicate an astrocytoma. However, new, persistent or unexplained neurological symptoms should be assessed by an appropriate healthcare professional.

How is an astrocytoma diagnosed?

Diagnosis usually involves several stages.

1. Neurological assessment

A specialist will discuss the symptoms, their development and any relevant medical history. A neurological examination may also assess areas such as movement, sensation, coordination, vision and cognitive function.

If the assessment suggests that further investigation is needed, brain imaging may be arranged.

2. MRI scanning

Magnetic resonance imaging (MRI) is one of the most important tools for assessing a suspected brain tumour.

MRI uses magnetic fields and radio waves to produce detailed images of the brain. Different MRI techniques can provide information about the location, size and appearance of a tumour and its relationship with surrounding brain structures.

Imaging can help specialists determine whether a lesion has characteristics that require further investigation, while also helping with treatment planning.

3. Tissue and pathology assessment

Imaging alone cannot always provide a definitive diagnosis. Where appropriate, a biopsy or surgical procedure may be used to obtain tumour tissue.

A specialist neuropathologist examines the tissue under a microscope and assesses its cellular characteristics. This helps establish the tumour type and other important features.

4. Molecular and genomic testing

Modern brain tumour diagnosis increasingly involves molecular testing alongside traditional pathology.

Tests can identify specific genetic or molecular alterations within tumour cells. These findings can help specialists classify the tumour more precisely and provide information that may influence treatment planning.

This is particularly important because two tumours that appear similar under a microscope may have different molecular characteristics and therefore require different clinical approaches.

What does tumour grade mean?

Astrocytomas can be assigned different grades according to their biological characteristics. The grade provides information about the tumour's characteristics and helps specialists understand how it is likely to behave.

However, grades are only one part of the overall diagnosis. The precise classification may incorporate both microscopic findings and molecular information. This reflects the increasingly sophisticated way in which brain tumours are diagnosed and categorised.

What happens after an astrocytoma diagnosis?

Once the diagnosis has been established, specialists consider the full clinical picture. This can include the tumour's location and characteristics, molecular findings, symptoms, previous treatment and the individual's overall circumstances.

Treatment may involve one or more specialist approaches, depending on the particular diagnosis.

For some patients, surgery may form part of their astrocytoma treatment pathway, while radiotherapy, systemic treatments or specialist radiosurgical techniques may also be considered where clinically appropriate.

A multidisciplinary approach can be particularly valuable for complex brain tumours, bringing together relevant specialists to review diagnostic information and develop an individualised treatment plan.

For patients and families, receiving a diagnosis can raise many questions. A specialist consultation provides an opportunity to understand the diagnosis, discuss the available treatment options and consider whether a second opinion would be helpful.

Why specialist diagnosis matters

Astrocytomas can be complicated to diagnose and classify. Advances in MRI, neuropathology and genomic testing mean that specialists can now build a much more detailed understanding of an individual tumour.

For someone who has been diagnosed with an astrocytoma, understanding exactly what type of tumour is present and which molecular characteristics it has can be an important part of determining the next stage of care.

Explore the Queen Square website to learn more about specialist assessment, advanced diagnostics and treatment options for complex brain tumours, including astrocytoma.