Medulloblastoma in Children — a treatable childhood brain tumour, explained for parents

Brain Cancer  /  Childhood brain tumours  /  Medulloblastoma

Medulloblastoma — the most common childhood brain cancer

Medulloblastoma is a fast-growing cancer that starts in the cerebellum, the part at the back of the brain that controls balance and coordination. It is the most common malignant (cancerous) brain tumour in children, most often diagnosed before the age of ten. It is serious because it can spread through the fluid around the brain and spinal cord — but it is also one of the most treatable childhood brain cancers, and many children are cured.

This page is written for parents and carers. Childhood cancer needs a paediatric team, so at CION medulloblastoma and other childhood brain tumours are managed under our Pediatric Cancer hub, where paediatric-trained oncologists lead the care. Use this page to understand the signs and the treatment journey, then talk to us for guidance specific to your child.

Signs of Medulloblastoma in a Child

Headaches, tiredness and clumsiness are extremely common in childhood, and are almost always caused by everyday things — infections, growth spurts, tiredness or minor knocks — not a brain tumour. Medulloblastoma is rare. But because it sits near the brain's fluid pathways, it can raise pressure inside the head, and that produces a specific pattern worth knowing.

See a doctor promptly if your child has these signs that are new, persistent and getting worse:

• Morning headaches with vomiting — often without much nausea, and the child may feel better after being sick
• Headaches that wake a child from sleep or steadily worsen over days to weeks
• New clumsiness or unsteady walking — stumbling, falling, or trouble with balance and coordination
• Double vision, a new squint, or eyes that seem to wobble
• A tilted head held to one side, or a stiff neck
• Increasing tiredness, irritability or being "not themselves" over time

Trust your instinct. These signs usually have an innocent cause, but a combination of morning headache, vomiting and unsteadiness deserves quick medical review — usually a brain MRI. Early diagnosis gives the best options. Speak to a CION specialist if you are worried.

How Medulloblastoma Is Diagnosed

Diagnosing medulloblastoma is careful, step-by-step work. Because the tumour can spread through spinal fluid, doctors look at the whole brain and spine before deciding on treatment.

MRI of the brain

An MRI with contrast is the best scan for showing a tumour in the cerebellum. It shows the size, exact position, and whether fluid is building up inside the brain (hydrocephalus), which is common with medulloblastoma and may need urgent relief.

MRI of the whole spine and spinal-fluid check

Because medulloblastoma can shed cells into the cerebrospinal fluid, doctors do an MRI of the entire spine and often examine a sample of spinal fluid (a lumbar puncture). This tells the team whether the cancer has spread — a key factor in the risk group and treatment plan.

Tissue confirmation and molecular subgrouping

The diagnosis is confirmed on tumour tissue after surgery, then sent for molecular testing that sorts the tumour into the WNT, SHH, Group 3 or Group 4 subgroup. This modern classification strongly influences prognosis and how intensive treatment needs to be. CION arranges the imaging, spinal-fluid work-up and molecular testing, and reviews every case at a multidisciplinary tumour board.

The Four Molecular Subgroups — Why They Matter

Two children can have "medulloblastoma" and yet need very different treatment. Since the 2021 WHO classification, the tumour is defined not just by how it looks under the microscope but by its molecular subgroup. These broad patterns help the team judge risk and tailor how strong treatment should be:

• WNT-activated — generally carries the most favourable outlook; teams may study de-intensified treatment to reduce long-term side effects
• SHH-activated — behaves differently by age; some infants and some adults fall in this group, and outcomes vary
• Group 3 — tends to be higher risk, more often with spread at diagnosis
• Group 4 — the most common subgroup; outlook is intermediate and depends on other factors such as spread

Your child's neuro-oncology team explains which subgroup applies and what it means in plain language.

How Medulloblastoma Is Treated

Treatment for medulloblastoma usually combines three approaches, planned together by a paediatric neuro-oncology team. The exact plan depends on your child's age, risk group and molecular subgroup.

1. 1
   Surgery — removing as much of the tumour as safely possible, and relieving fluid build-up if needed. At CION this is coordinated with accredited neurosurgical partners; how much tumour is removed is an important factor in the outlook.
2. 2
   Radiation therapy — for most children over three, radiation is given to the whole brain and spine (craniospinal radiation) because the cancer can travel through spinal fluid. CION delivers radiation with modern precision techniques to protect healthy, developing tissue. In children under about three, radiation is often delayed or avoided to protect the developing brain.
3. 3
   Chemotherapy — combination chemotherapy is given to lower the chance of the cancer returning; in very young children it may be used first to delay or avoid radiation. The drugs and intensity are chosen by risk group and molecular subgroup.

Alongside these, the team manages hydrocephalus, nutrition, hormone levels, and rehabilitation — physiotherapy, speech and cognitive support — to help children recover and thrive. CION delivers radiation therapy, systemic (drug) therapy, imaging, molecular testing and supportive care directly, and coordinates neurosurgery with accredited neurosurgical partners. Care follows NCCN and international paediatric protocols.

Ready to talk it through? Book a free consultation or call 18002028726 and we will guide you to CION's paediatric cancer team.

When to Get a Second Opinion

A second opinion is a normal, sensible step in childhood brain cancer — not a sign of doubt in your current team. It is especially worthwhile when:

• Molecular subgrouping has not been arranged — WNT, SHH, Group 3 or Group 4 status now guides how intensive treatment should be
• You want the whole plan reviewed together — surgery, radiation and chemotherapy should fit one coordinated pathway
• You want to understand the options around delaying radiation in a very young child, or reducing long-term side effects
• You simply want clarity and confidence before treatment begins

CION offers a free written second opinion. Because this is a childhood cancer, we will connect you with our Pediatric Cancer team and, where helpful, our wider brain tumour treatment specialists.

Childhood Cancer Care at CION

Children are not small adults. Their cancers, their bodies and their needs are different — so medulloblastoma and other childhood cancers are cared for by paediatric-trained teams under CION's dedicated hub.

Not sure where to start? Call 18002028726 and our team will point you to the right paediatric pathway.

Not Sure About Your Child's Treatment Plan?

Get a free written second opinion from CION's oncology team — especially valuable before treatment begins, or if molecular subgrouping has not yet been arranged.