What is a medulloblastoma?
Medulloblastomas are the most common high grade childhood brain tumour, accounting for 15-20% of all childhood brain tumours.
If your child or a child you know has recently been diagnosed with a medulloblastoma, you may be worried about what this means. This is a natural way to feel. Our Support and Information team can help answer any questions you may have or provide a listening ear if you need one.
What is a medulloblastoma?
Medulloblastomas are the most common central nervous system (CNS) embryonal tumour and account for 15-20% of all childhood brain tumours.
- fast growing
- likely to spread to other areas of the brain or spinal cord.
Medulloblastomas usually develop in a part of the brain called the posterior fossa and are most commonly found in the cerebellum, an area of the posterior fossa that controls coordination and balance.
They are commonly found in children between the ages of 3 and 8, with a higher occurrence in males.
In the past few years, research has significantly advanced our understanding of medulloblastomas and we’re now able to put them into 4 main groups based on demographic, clinical and genetic differences.
The genetic test to determine the type of medulloblastoma that your child may have is now available on the NHS.
This test will also help your medical team to tell you if your child could sign up to be part of clinical trials. One of the trials available is called PNET5, you can read more about it here.
This is the best known subgroup of all the medulloblastomas and has been identified in 10-15% of patients. The average age of occurrence is 10 years old and it is more commonly found in females.
These tumours often occupy the fourth ventricle; the fluid filled space in the middle of the posterior fossa.
This type of medulloblastoma frequently occurs in both infants (under three) and adults (over 16), but are less frequent in children aged three to sixteen.
SHH medulloblastoma is commonly associated with a condition known as Gorlin syndrome, due to a gene mutation that causes the over-activation of cells, leading to the formation of a tumour.
This type of medulloblastoma occurs more commonly in males than females, and are most common in young children ranging from one to ten years old.
At diagnosis, these are often metastatic (already spread to other parts of the brain and spinal cord). Similar to the WNT medulloblastomas, the tumour is generally located within the fourth ventricle.
This is the most common subgroup of medulloblastoma, making up around 35-40% of all cases. These tumours can occur in all ages but are most prevalent in mid-childhood.
What are the symptoms of a medulloblastoma?
As well as the symptoms common across many childhood brain tumours, the location of a medulloblastoma is likely to cause increased pressure in the skull. Medulloblastoma symptoms will therefore likely include:
- abrupt onset of headaches, especially in the morning
- nausea and/or vomiting
- feeling extremely tired
- loss of balance and co-ordination which may lead to difficulty walking
- abnormal eye movements
- blurry vision caused by swelling of the optic disc at the back of the eye (papilloedema).
In some cases, the tumour can spread to the spinal cord, causing another set of symptoms, such as back pain, an inability to control the bowels and bladder and difficulty walking.
Lucy Bennet, diagnosed with a medulloblastoma in 1998, aged 3
“I was only three when I was diagnosed on holiday with my family in France.
“Once home I had surgery, radiotherapy, and a Hickmann line was put in to give me chemotherapy. But this couldn’t get wet.
“So finishing treatment and being able to have a bubble bath stood out for me, even more than presents from Santa.
“I now take growth hormone every day and vitamin D3, as the radiotherapy left me with low bone density. I sometimes take a little longer to understand information – but this hasn’t stopped me from passing my GCSEs, A-levels and going to Canterbury University to do a degree in Early Childhood Studies.
“More recently, I’ve had seizures and times when my writing hand freezes, making me struggle with my confidence and self-esteem.
“But even more recently, I joined a closed support group on Facebook and went to charity events for young adults affected by a brain tumour.
“I used to feel nervous when meeting groups of people I didn’t know, but not anymore. My life has changed for the better.
Join one of our Online Support Communities for more stories and tips about coping with a brain tumour diagnosis from people who know what you’re going through.
How are medulloblastomas treated?
Treatment for medulloblastoma is likely to include a combination of surgery, radiotherapy and chemotherapy.
The first course of treatment is usually neurosurgery to remove the tumour. However, if your child’s tumour has caused a build-up of CSF, the surgeon may first need to perform an operation to reduce the pressure.
Following surgery, radiotherapy is often used to destroy any remaining tumour cells. It is normally given to the whole brain and spinal cord as medulloblastomas can travel through the CSF to the spinal cord.
If a child is aged under 3, whole brain radiotherapy is usually avoided and high-dose chemotherapy may be used to delay or eliminate the need for radiotherapy.
In some cases, children older than 3 may be given several cycles of high-dose chemotherapy before or after radiotherapy.
Join our community on Facebook
Our closed Facebook group for parents is a great place to connect with other parents affected by a brain tumour and share your experiences.
What causes medulloblastomas?
It’s important to understand that nothing you’ve done or could have avoiding doing would have prevented a brain tumour from developing.
As with all brain tumours, we don’t know for sure what causes medullblastomas to start growing, although we do understand some of the risk factors involved.
SHH medulloblastomas in particular are commonly associated with a condition known as Gorlin syndrome, due to a gene mutation that causes the over-activation of cells, leading to the formation of a tumour.
How long can somebody live with a medulloblastoma?
There is no way to know for certain. While averages can be given, everybody is different – it will depend on so many factors – not only your tumour grade, size and location, but also your general health, your individual body chemistry, and how you respond to treatment.
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Dr Gajjar discusses embryonal tumours, including Medulloblastoma, PNET and ATRT and NPID, National Paediatric Information Day, 2016.