Medulloblastoma

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

To get an accurate diagnosis, a piece of tumor tissue will be removed during surgery, if possible. A neuropathologist should then review the tumor tissue.  Medulloblastoma is a cancerous (malignant) brain tumor that begins in the cerebellum, which is located in the bottom back of the brain. Muscle coordination, balance, and movement are all controlled by the cerebellum.

Medulloblastoma spreads to other parts of the brain and spinal cord through cerebrospinal fluid (CSF), the fluid that surrounds and protects the brain and spinal cord. Rarely does this tumor spread to other parts of the body.

Medulloblastoma is a form of embryonal tumor that begins in the brain’s foetal (embryonic) cells. There are at least four varieties of medulloblastoma based on distinct types of gene mutations. Although medulloblastoma is not inherited, disorders such as Gorlin’s or Turcot’s syndrome may raise the incidence of the disease.

Headaches, nausea, vomiting, weariness, dizziness, double vision, poor coordination, unsteady walking, and other symptoms are all signs and symptoms of medulloblastoma. These symptoms could be caused by the tumor or by a buildup of pressure inside the brain.

Medulloblastoma can affect anyone at any age; however, it is most common in young children. Medulloblastoma is the most frequent malignant brain tumor in children, despite its rarity. Children should be seen by a team of pediatric specialists with expertise and experience in pediatric brain tumors, as well as access to the most up-to-date technologies and treatments for children.

Grades of medulloblastoma

Primary CNS tumors are graded based on the tumor location, tumor type, extent of tumor spread, genetic findings, the patient’s age, and tumor remaining after surgery, if surgery is possible.

Medulloblastomas are all classified as Grade IV tumors. This means they are malignant (cancerous) and fast-growing.

There are four subtypes that have been identified in children with medulloblastoma.

1. WNT-activated
2. SHH-activated
3. Group 3 (non-WNT/non-SHH)
4. Group 4 (non-WNT/non-SHH)

In adults with medulloblastoma, these subtypes are not as well defined as they are in children.

Diagnosis of medulloblastoma

Treatment of medulloblastoma

Symptoms related to a medulloblastoma depend on the tumor’s location. Here are some possible symptoms that can occur.

Medulloblastoma Symptoms

People with a medulloblastoma in the cerebellum may have:

• Issues with walking, balance, and/or fine motor skills

If the tumor is blocking the CSF, this can lead to increased pressure inside the skull. This problem is known as hydrocephalus.

Signs and symptoms of hydrocephalus may include:

• Headaches
• Nausea
• Vomiting
• Blurred and double vision
• Extreme sleepiness
• Confusion
• Seizures and even passing out

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

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

The process of diagnosis usually starts with a medical history review and a discussion of signs and symptoms. Tests and procedures used to diagnose medulloblastoma include:

• Neurological exam: During this procedure, vision, hearing, balance, coordination, and reflexes are tested. This test helps determine which part of the brain might be affected by the tumor.
• Imaging tests: Imaging tests can help determine the location and size of the brain tumor. These tests are also critical to identify pressure or blockage of the CSF pathways. A computerized tomography (CT) scan or magnetic resonance imaging (MRI) may be done right away. These tests are often used to diagnose brain tumors. Advanced techniques, such as perfusion MRI and magnetic resonance spectroscopy, also may be used.
• Tissue sample testing (biopsy): A biopsy is usually not done, but it may be recommended if the imaging tests are not typical of medulloblastoma. The sample of suspicious tissue is analyzed in a lab to determine the types of cells.
• Removal of cerebrospinal fluid for testing (lumbar puncture): Also called a spinal tap, this procedure involves inserting a needle between two bones in the lower spine to draw out cerebrospinal fluid from around the spinal cord. The fluid is tested to look for tumor cells or other abnormalities. This test is only done after managing the pressure in the brain or removing the tumor.

The most typical treatment for medulloblastoma is surgery to remove the tumor, followed by radiation and chemotherapy. Clinicians at St. Jude have created risk-based therapy based on the various molecular groups. This method is utilized to improve survival rates while reducing treatment-related negative effects. If the patient’s prognosis is favorable, a lower-intensity treatment may be recommended. Patients with high-risk disease may receive more intense treatment to increase their chances of survival.

• Surgery: is usually the first step to treating medulloblastoma. The goal is complete removal of the tumor. The surgery’s success can depend on the tumor’s location and how much can be removed safely.
• Radiation therapy: Uses high-energy X-rays or other types of radiation, such as proton beam radiation, to kill cancer cells or stop them from growing. The dose given depends on the stage of the disease and the risk category. Radiation may be combined with chemotherapy to improve outcomes.
  • Proton beam radiation is another form of radiation therapy. This type of radiation uses protons instead of X-rays. The protons can be adjusted to stop at the tumor instead of going through the body and affecting healthy tissue like X-rays can do.
• Chemotherapy: uses powerful medicines to kill cancer cells or stop them from growing (dividing) and making more cancer cells. For young children, chemo may be offered to delay radiation until the patient is older. Some types of medulloblastoma may be successfully treated with only chemo.