Diagnosis

Diagnosis usually begins with a physical exam, review of medical history and a discussion of symptoms.

Tests and procedures used to diagnose medulloblastoma include:

  • Neurological exam. The exam tests vision, hearing, balance, coordination and reflexes. It can help show which part of the brain may be affected by the tumor.
  • Imaging tests. Imaging tests take pictures of the brain. MRI is the main test used to diagnose medulloblastoma. A brain MRI can show the size and location of the tumor. It also can show increased pressure or a blockage in the flow of cerebrospinal fluid. MRI of the spine is often done to check whether the tumor has spread through cerebrospinal fluid. This helps determine the risk group of the cancer. Brain CT scans may be used in certain situations, including emergencies.
  • Tissue sample testing. A tissue sample is usually taken during surgery to remove the tumor. This procedure is called a brain biopsy. A biopsy is a procedure to remove a sample of tissue for testing in a lab. The sample is tested in a lab to confirm that it is medulloblastoma. A separate biopsy alone is uncommon and is used only in certain situations.
  • Removal of cerebrospinal fluid for testing. A lumbar puncture involves inserting a needle between two bones in the lower back. The needle removes cerebrospinal fluid from around the spinal cord. The fluid is tested in a lab to look for tumor cells. This test is done only after pressure in the brain is treated or after surgery.

Medulloblastoma is classified as a grade 4 tumor. In brain tumors, grade refers to how fast the tumor is likely to grow and how aggressive it may be if not treated. Grade 4 tumors tend to grow quickly and require prompt treatment. Doctors use imaging results, spinal fluid testing and lab testing of the tumor to determine the tumor's risk group and guide treatment.

Treatment

Treatment for medulloblastoma usually includes surgery followed by radiation therapy, chemotherapy or both. Many children can be treated successfully, especially when the tumor is found early and has not spread.

The exact treatment plan depends on several factors, including:

  • How much of the tumor can be safely removed.
  • Whether the tumor has spread to the brain or spinal cord.
  • The results of lab tests on the tumor.
  • The person's age and overall health.

Doctors use this information to decide how strong the treatment needs to be. Some tumors require more-intensive treatment, while others may be treated with lower doses to reduce long-term side effects.

Treatment options include:

  • Surgery to relieve fluid buildup in the brain. A medulloblastoma may block the flow of cerebrospinal fluid. This can cause fluid to build up and increase pressure in the brain, which is called hydrocephalus. To reduce the pressure, a surgeon may create a new pathway for the fluid to drain safely. Sometimes this is done at the same time as tumor removal.
  • Brain tumor surgery to remove the medulloblastoma. The goal is to remove as much of the tumor as safely possible. Sometimes the tumor cannot be fully removed because it is close to parts of the brain involved in walking, talking and other important functions. Most people need more treatment after surgery to destroy remaining cancer cells.
  • Radiation therapy. Radiation therapy uses high-energy beams to kill cancer cells. Radiation is usually given to both the brain and spinal cord, followed by a focused boost to the area where the tumor started. Proton beam therapy may be used in some centers to reduce radiation to nearby healthy tissue. Radiation therapy is often given after surgery.
  • Chemotherapy. Chemotherapy treats cancer with strong medicines. These medicines are usually given through a vein. Chemotherapy may be given after surgery, after radiation therapy or at the same time as radiation. In very young children, chemotherapy may be used to delay or avoid radiation therapy to protect the developing brain.
  • Clinical trials. Clinical trials study new treatments or new ways to combine surgery, radiation and chemotherapy. Participation may provide access to newer therapies. Talk with your healthcare professional to learn if a clinical trial may be an option.

Treatment in children versus adults

Treatment for medulloblastoma is similar in children and adults, but there are important differences. Older children often receive radiation to the brain and spinal cord followed by chemotherapy. In very young children, doctors may delay or reduce radiation to protect the developing brain.

Adults also may receive surgery, radiation and chemotherapy. But treatment plans for adults may be adjusted based on age, overall health and side effects.

Clinical trials

Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this condition.

Preparing for your appointment

Make an appointment with a doctor or other healthcare professional if you have any symptoms that worry you.

Because appointments can be brief, it's a good idea to be prepared. Here's some information to help you get ready.

What you can do

  • Be aware of anything you need to do ahead of time. At the time you make the appointment, be sure to ask if there's anything you need to do in advance, such as restrict your diet.
  • Write down symptoms you have, including any that may not seem related to the reason for which you scheduled the appointment.
  • Write down important personal information, including major stresses or recent life changes.
  • Make a list of all medicines, vitamins or supplements you're taking and the doses.
  • Take a family member or friend along. Sometimes it can be very hard to remember all the information provided during an appointment. Someone who goes with you may remember something that you missed or forgot.
  • Write down questions to ask your healthcare team.

Your time with your healthcare team is limited, so preparing a list of questions can help you make the most of your time together. List your questions from most important to least important in case time runs out. For medulloblastoma, some basic questions to ask include:

  • Do I have a medulloblastoma?
  • Will I need more tests?
  • Can my medulloblastoma be removed?
  • Why do I need additional treatments if surgery removes the entire medulloblastoma?
  • What are the treatment options?
  • What is the stage of my medulloblastoma?
  • Has my medulloblastoma spread to other parts of my body?
  • How much does each treatment increase my chances of a cure or prolong my life?
  • What are the potential side effects of each treatment?
  • How will each treatment affect my daily life?
  • Is there one treatment option you believe is the best?
  • What would you recommend to a friend or family member in my situation?
  • Should I see a specialist?
  • Are there any brochures or other printed material that I can take with me? What websites do you recommend?
  • What will determine whether I should plan for a follow-up visit?
  • Will I need to continue coming back?

Don't hesitate to ask other questions.

What to expect from your doctor

Be prepared to answer questions, such as:

  • When did your symptoms begin?
  • Have your symptoms been continuous or occasional?
  • How severe are your symptoms?
  • What, if anything, seems to improve your symptoms?
  • What, if anything, appears to worsen your symptoms?
April 10, 2026

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