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What Is Medulloblastoma?

Medulloblastoma (meh-dull-oh-blass-TOE-muh) is a cancerous type of brain tumor. It develops in the cerebellum, a part of the brain near the bottom of the skull. Medulloblastoma can spread to the central nervous system (the brain and spinal cord).

Most brain tumors in children are medulloblastoma.

What Are the Signs & Symptoms of Medulloblastoma?

Sometimes brain cells grow in a way they shouldn't and form a tumor . A tumor in the cerebellum can increase pressure inside the brain when it presses on other parts of the brain.cerebellum illustration

As the pressure gets higher, it begins to cause symptoms. These get worse over a few weeks to a few months.

Symptoms that parents might notice include:

  • nighttime or early-morning headaches
  • nausea
  • vomiting
  • trouble walking
  • dizziness
  • double vision
  • clumsiness

What Causes Medulloblastoma?

Doctors don't know what causes medulloblastoma. A few children who have it are thought to have a genetic problem that puts them at risk for this type of brain tumor.

Who Gets Medulloblastoma?

Medulloblastoma usually affects children between 5 and 9 years old. Most cases are diagnosed before age 20. It's rare in adults.

How Is Medulloblastoma Diagnosed?

Doctors often do an MRI (magnetic resonance imaging) of the brain to check for a tumor. This is a safe way to get detailed images of the brain without using radiation.

If a brain tumor is found, the surgeon does an operation to get a sample of the tumor (a biopsy), and removes some or all of the tumor when possible. Tumor cells are examined, and identifying the types of cells can confirm a medulloblastoma diagnosis.

Some of the tumor cells undergo genetic testing to look for changes in the DNA known as molecular markers. These markers are specific pieces of DNA that can identify different types of medulloblastoma, called subtypes. Doctors make a treatment plan after learning the subtype.

How Does Medulloblastoma Spread?

Cancer cells from the tumor can spread throughout the central nervous system. To see if they have, doctors may order these tests:

  • an MRI of the spine to see if the cells have spread to the spinal cord
  • a lumbar puncture (spinal tap) to get a small sample of cerebrospinal fluid (CSF) to check for cancer cells

How Is Medulloblastoma Treated?

Doctors usually treat medulloblastoma with a combination of surgery, chemotherapy, and radiation therapy. When making a treatment plan, they'll consider:

  • the child's age
  • the size of the tumor
  • the tumor cell type
  • molecular markers

Surgery is usually done to remove as much of the tumor as possible. Then chemotherapy (chemo) uses medicines to kill cancer cells. 

Radiation therapy uses X-rays (photon therapy) or proton beam therapy to kill cancer cells and shrink tumors. It's often used to destroy the cancer cells still in the brain after surgery and cancer cells in the spinal cord. Doctors prefer not to use radiation therapy in children 3 years old or younger to give the brain and spine more time to grow.

Looking Ahead

Having a child going through cancer treatment can be stressful for any family. But you're not alone. The care team is there to support you and your child. Online resources that can help you along the way include:

Reviewed by: Andrew W. Walter, MD
Date Reviewed: 27-08-2018

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