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Medulloblastoma
Medulloblastoma is the most common type of malignant brain cancer in children and teens, although adults can get it, too. These tumors grow in the back part of the brain called the cerebellum. They often require intense treatment.
On this page
- What is medulloblastoma?
- How common is medulloblastoma? Who gets it?
- Signs and symptoms of medulloblastoma
- How is medulloblastoma diagnosed?
- Medulloblastoma types
- Prognostic factors and risk groups
- Treating medulloblastoma
- Life after treatment for medulloblastoma
- Key points to remember
- Tools & Resources
- News & Stories
What is medulloblastoma?
Medulloblastoma is an embryonal tumor, meaning it grows from early forms of nervous system cells involved in brain cell development.
How common is medulloblastoma? Who gets it?
About 300 to 400 medulloblastomas are diagnosed in the United States each year. Most are in children. About 1 in 5 cancerous brain tumors in children is a medulloblastoma.
Medulloblastoma is most common in children aged 1 to 9, but it can develop in infants, teens, and adults as well. It is more common in males and non-Hispanic White people.
People with certain family cancer syndromes have a higher risk of developing a medulloblastoma. These include:
- Familial adenomatous polyposis (FAP)
- Gorlin syndrome (nevoid basal cell carcinoma syndrome)
- Li-Fraumeni syndrome
- Nijmegen breakage syndrome
- Ataxia-telangiectasia
- Fanconi anemia
- Rubinstein-Taybi syndrome
But most people with medulloblastoma do not have a family cancer syndrome.
Unlike many adult cancers, lifestyle-related risk factors like body weight, physical activity, diet, and the use of tobacco and alcohol do not play a major role in pediatric cancers. So far, researchers have not found any outside factors that raise the risk of medulloblastoma.
Signs and symptoms of medulloblastoma
Medulloblastomas usually cause symptoms when they block the flow of cerebrospinal fluid (CSF) around the brain and spinal cord, leading to increased pressure inside the skull. These symptoms can include:
- Headaches, especially at night or early in the morning
- Nausea or vomiting
- Low energy
- Trouble with balance or walking
- Abnormal eye movements
- Swelling of the optic nerve in the back of the eye due to high pressure from CSF build up
In younger children and infants, symptoms may be more subtle, such as changes in energy level, trouble eating, an enlarged head, or a loss of motor skills like walking or crawling.
To learn more about symptoms of brain tumors, see Signs and Symptoms of Brain Tumors in Children.
How is medulloblastoma diagnosed?
Doctors can often tell that a person most likely has a medulloblastoma based on imaging test results. For example, a tumor seen in the cerebellum in a child is more likely to be a medulloblastoma. But a biopsy is needed to confirm the diagnosis, as well as to learn more about the tumor.
Because medulloblastomas can spread in the CSF, imaging of both the brain and spinal cord is done to see how far the tumor has spread. The 2 most common imaging tests used are:
- MRI scan: This is the preferred test for looking at most tumors in the brain. The images are very detailed and can show the size, shape, and location of the tumor. Contrast, such as gadolinium, may be injected into a vein before one set of scans to help show details better.
- CT scan: This test uses x-rays to make detailed cross-sectional images of the brain. It can be done quickly and may be the first imaging test done, especially in an urgent situation such as after a seizure or severe symptoms.
If a tumor is causing symptoms or the diagnosis is not clear from imaging tests, a biopsy may be needed. For medulloblastoma, a biopsy is most often done as part of surgery to remove the entire tumor, if possible.
The biopsy sample is looked at under the microscope. The doctor looks at the cell type and how fast the cells appear to be growing and dividing.
Molecular testing is also done to test the tissue for certain gene or protein changes. Some of these changes are linked to how the tumor behaves and may help guide treatment decisions.
Medulloblastoma can spread through the CSF to other parts of the central nervous system (CNS, the brain and spinal cord). Knowing whether medulloblastoma cells are in the CSF is important for treatment planning. CSF can be collected for testing during a lumbar puncture (spinal tap).
For more on these and other tests, see Tests for Brain Tumors in Children.
Medulloblastoma types
Medulloblastoma can be grouped into types based on histology (how the tissue looks under the microscope) or molecular tests, which look for specific gene changes in the tumor.
Based on histology, the 4 main types of medulloblastoma are:
- Classic medulloblastoma
- Desmoplastic nodular medulloblastoma
- Medulloblastoma with extensive nodularity
- Large cell/anaplastic medulloblastoma
Based on molecular tests, medulloblastoma may be:
- WNT-activated
- SHH-activated, with TP53 gene changes
- SHH-activated, without TP53 gene changes
- Non-WNT/non-SHH–activated (includes groups 3 and 4)
These subtypes are used in some clinical trials and may help doctors predict a person’s outlook (prognosis).
Prognostic factors and risk groups
A risk group is a way to group people with cancer based on how likely the cancer is to come back or grow after treatment. Risk groups for medulloblastoma are based on:
- Imaging tests looking for spread of medulloblastoma through the CNS
- CSF (lumbar puncture) test results
- Histology results from the tumor biopsy
- Imaging tests after surgery to see how much tumor is left
Factors that have been linked with a better outlook (prognosis) include tumors that:
- Are localized (no spread to other parts of the CNS or beyond)
- Can be removed completely with surgery
- Occur in children age 3 years or older
- Are desmoplastic nodular and extensive nodularity types in children younger than 3
- Have certain gene changes in tumor cells, like WNT-activation
For children and young adults aged 3 years or older the risk groups are:
- Average risk: Tumors that are completely or almost completely removed (less than 1.5 cm2 remains after surgery), without any evidence of spread.
- High risk: Tumors where a portion was left after surgery (at least 1.5 cm2), disease that has spread outside of the back part of the brain, and/or anaplasia on the biopsy sample.
Similar risk groups have been used in clinical trials of younger children with medulloblastoma as well.
Treating medulloblastoma
Most people with medulloblastoma are treated with a combination of surgery, radiation, and chemotherapy.
For children under 3 years old, radiation treatments are avoided whenever possible. Because of the side effects of radiation on the young brain, these children may be treated with only surgery and chemotherapy. This approach may be all that’s needed for some young children. In others, it may delay the need for radiation until the child is older, when side effects may be less.
The goals of surgery for medulloblastoma are to:
- Get tumor tissue for a diagnosis
- Remove as much of the tumor as is safe (maximally safe resection)
- Relieve symptoms from the tumor itself or from increased pressure inside the skull on surrounding normal brain tissue
Surgery is usually done by craniotomy, a surgical opening in the skull, to remove the brain tumor. A child often has part or all of their hair shaved to prepare for surgery.
Sometimes a shunt is placed to allow the CSF to flow properly after the tumor is removed.
Total removal of a medulloblastoma is usually linked with a better outlook when it is safe to do so.
To learn more, see Surgery for Brain Tumors in Children.
After surgery, for people aged 3 or older, radiation to the brain and spinal cord is typically recommended to try to kill any remaining cancer cells. This is known as craniospinal RT. It’s usually done 5 days a week for about 6 weeks.
Radiation treatments are like getting an x-ray, but the dose of radiation is much higher. The sessions only last 15 to 30 minutes, and most of that time is spent making sure the radiation is aimed correctly. Young children may need medicine to make them sleep so they will be still during the treatment.
Proton beam radiation, instead of the more common photon radiation, is often recommended to treat medulloblastoma. This type limits the radiation to other parts of the brain and body, causing less damage to surrounding healthy tissues.
Proton beam radiation may not be available everywhere. Sometimes families may have to travel for treatment if the doctors think proton beam radiation is the best treatment option.
To learn more, see Radiation Therapy for Brain Tumors in Children.
Chemotherapy (chemo) is the use of drugs to treat cancer. Chemo drugs used to treat medulloblastoma can include:
- Cyclophosphamide
- Etoposide
- Cisplatin
- Vincristine
- Lomustine
- Methotrexate
Other chemo drugs like temozolomide, irinotecan, and carboplatin might be used if medulloblastoma doesn’t respond initially or if it returns after treatment.
Chemo drugs can cause side effects during treatment, such as nausea, vomiting, low appetite, hair loss, hearing loss, kidney problems, and nerve pain. Other side effects are also possible with certain drugs. Doctors will watch closely for side effects, treat them, and adjust chemo doses if needed.
For more on chemo, see Chemotherapy and Supportive Care Medicines for Brain Tumors.
As doctors learn more about the gene changes that cause tumors like medulloblastoma, newer targeted drugs are being developed that may help treat these cancers. For example:
- Vismodegib, a drug that targets changes in the SHH pathway, may be useful in treating SHH-activated medulloblastomas.
- Other targeted drugs like bevacizumab, which works to block new blood vessel growth, might also be used in medulloblastoma if it doesn’t respond well to other treatments.
Clinical trials are studying high-dose chemotherapy with stem cell transplant as an option for medulloblastoma treatment.
Researchers are also studying chemo given into the cerebrospinal fluid (CSF) (intraventricular chemo) as another way to treat medulloblastomas.
Some of these approaches may be tried as part of a clinical trial, or if medulloblastoma comes back after treatment.
Life after treatment for medulloblastoma
After treatment, doctors will want to schedule regular follow up exams to make sure the tumor has not come back and to check for any new symptoms or complications from the tumor and its treatment. At first, these visits may be more frequent, and over time they will be less often.
These visits will include talking about any new symptoms and testing strength, feeling, memory, reflexes, and other functions to see how well the brain and nervous system are working. These visits will often include imaging tests for some time as well, to make sure the tumor hasn’t come back.
Side effects of the cancer and its treatment can occur long after treatment is finished. Side effects of medulloblastoma treatment depend on what treatments were used and how old you (or your child) were when they were given.
To find out more about long-term side effects of medulloblastoma and its treatment, see After Brain Tumor Treatment in Children.
Key points to remember
- Medulloblastoma is an embryonal tumor that starts in the back of the brain. It’s the most common brain cancer in children and teens, although it’s rare in adults.
- The outlook for medulloblastoma depends largely on the person’s age, how much of the tumor can be removed with surgery, and whether the tumor has spread. Some types of medulloblastoma may have a better or worse prognosis based on what they look like under the microscope (histology) and on certain gene changes in the cancer cells.
- For the best chance of cure, people aged 3 or older with medulloblastoma are typically treated with surgery, radiation and chemotherapy. Radiation is avoided when possible in children under age 3.
- Written by
- References
Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
Cotter JA, Hawkins C. Medulloblastoma: WHO 2021 and Beyond. Pediatr Dev Pathol. 2022;25(1):23-33.
Fangusaro J. Clinical presentation, diagnosis, and risk stratification of medulloblastoma. UpToDate. 2025. Accessed at https://www.uptodate.com/contents/clinical-presentation-diagnosis-and-risk-stratification-of-medulloblastoma on October 27, 2025.
Fangusaro J. Histopathology, genetics, and molecular groups of medulloblastoma. UpToDate. 2025. Accessed at https://www.uptodate.com/contents/histopathology-genetics-and-molecular-groups-of-medulloblastoma on October 27, 2025.
Fangusaro J. Treatment and prognosis of medulloblastoma. UpToDate. 2025. Accessed at https://www.uptodate.com/contents/treatment-and-prognosis-of-medulloblastoma on October 27, 2025.
Huang A, Lindsay H, Tamrazi B, et al. Chapter 22B: Tumors of the Central Nervous System: Embryonal and Pineal Region Tumors. In: Blaney SM, Adamson PC, Helman LJ, eds. Pizzo and Poplack’s Pediatric Oncology. 8th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2021.
National Cancer Institute. Childhood Medulloblastoma and Other Central Nervous System Embryonal Tumors Treatment (PDQ). 2025. Accessed at https://www.cancer.gov/types/brain/hp/child-cns-embryonal-treatment-pdq on August 28, 2025.
Last Revised: February 9, 2026
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