Medulloblastoma is a primary the central nervous system (CNS) tumor. This means that it begins in the brain or spinal cord.

To get an accurate diagnosisa piece of tumor tissue will be removed during the operation if possible. ONE neuropathologist should then undergo the tumor tissue.

What are the grades of medulloblastomas?

Primary CNS tumors are graded based on a tumor tissue analysis performed by a neuropathologist. Medulloblastomas are all classified as grade 4 (also written as grade IV) tumors. This means they are malignant (cancerous) and fast growing.

In addition, medulloblastomas needs staging-obtaining tests to detect whether the tumor has spread to other areas of the CNS or outside the CNS. Using the stage of the cancer, the patient’s age, and whether the tumor remains after surgery (if surgery is possible), a healthcare team can assess the risk of the tumor returning. This also helps them choose the best treatment. This process is called risk stratification, and medulloblastomas are classified into two risk groups: standard risk (or average risk) and high risk.

Currently, medulloblastomas are also classified based on their genetic characteristics. There are at least four subgroups that have been identified in children and adults, although their frequency and genetic characteristics vary depending on the patient’s age:

• WNT activated
• SHH-enabled
• Group 3 (non-WNT / non-SHH)
• Group 4 (non-WNT / non-SHH)

What do medulloblastomas look like on an MRI?

Medulloblastomas usually appear as a solid mass in the cerebellumwhich is the part of the brain in the back of the head between cerebrum and the brainstem. The tumor often brightens with contrast. It can also block the cerebrospinal fluid (CSF) pathways, causing an abnormal accumulation of fluid that increases pressure on the skull. This is known as hydrocephalus. When the mass is diagnosed as a medulloblastoma, a magnetic resonance imaging (MRI) scan of the spinal cord can show whether it has spread.

What causes medulloblastomas?

Cancer is a genetic disease – that is, it is caused by certain changes in annoyances which control the way our cells work. Genes can be mutated (changed) in many types of cancer, which can increase the growth and spread of cancer cells. The cause of most medulloblastomas is unknown. But there is a small percentage of medulloblastomas that are related to gene changes and can be passed down through families.

Where do medulloblastomas form?

Medulloblastomas most often form in the cerebellum, the lower part of the brain located at the back of the skull. Medulloblastomas are known as embryonal neuroepithelial tumors because they form in fetal cells that remain after birth.

Do medulloblastomas spread?

Medulloblastomas are very fast growing. They often spread to other areas of the CNS through the CSF. Medulloblastomas can also spread outside the CNS, for example to bones, lungs or the lymphatic system. This happens more frequently in children and in adults as well recurrent tumors.

What are the symptoms of a medulloblastoma?

Symptoms related to a medulloblastoma depend on the location of the tumor. Here are some possible symptoms that may occur.

People with medulloblastoma of the cerebellum may have:

If the tumor is causing hydrocephalus, signs and symptoms may include:

• Headache
• Nausea
• Vomiting
• Blurred and double vision
• Extreme sleepiness
• Confusion
• Seizures and even fainting

If a medulloblastoma has spread to the spine, symptoms may include:

• Weakness or numbness in arms and/or legs
• A change in normal bowel or bladder habits
• Spinal pain

If a medulloblastoma has spread to other organs, symptoms may include:

• Cough, chest pain and shortness of breath
• Enlarged lymph nodes
• Bone pain

Who is diagnosed with a medulloblastoma?

Seventy percent of medulloblastoma cases occur in children and 30 percent occur in adults. In adults, medulloblastoma typically affects those between the ages of 20 and 40.

Medulloblastomas occur more often in men than in women. They are most common in non-Hispanic white and Hispanic people. An estimated 6,070 people live with this tumor in the United States.

What is the prognosis for a medulloblastoma?

The probable outcome of the disease or the chance of cure is called prognosis. The relative five-year survival rate for medulloblastoma is 80.6 per cent. But many factors can affect the prognosis. These include the tumor molecular group, staging, extent of resection, the person’s age and health at diagnosis, and how they respond to treatment. If you want to understand your prognosis, talk to your doctor.

What are the treatment options for a medulloblastoma?

The first treatment for medulloblastoma is surgeryif possible. The goal of surgery is to get tissue to determine the type of tumor and remove as much tumor as possible without causing more symptoms to the person.

Most people with medulloblastoma also receive additional treatments. These may include radiation, chemotherapyor clinical trials. Because this disease tends to spread to the brain and spine, surgery is usually followed by radiation to the entire brain and spine (called craniospinal radiation). Proton beam therapy often recommended, due to problems with bone marrow and surrounding organs arising from brain and spine radiation.

Chemotherapy is often part of the treatment plan, depending on the tumor subtype, how far the tumor has spread, how the person responds to the treatment, the side effects, and the impact on their quality of life.

Clinical trials – with new ones chemotherapy, targeted therapyor immunotherapy substances – may also be available. It is important to seek expert recommendations from a neuro-oncologist experienced in adult medulloblastoma. Treatments are decided by the patient’s healthcare team based on the patient’s age, tumor remaining after surgery, tumor type and tumor location.

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