What to Expect From a Medulloblastoma

A medulloblastoma is a type of brain cancer. Brain cancer is a tumor in the brain. In general, tumors in the brain can originate in the brain itself, or they can originate in a different location and metastasize (spread) to the brain. A medulloblastoma is one of the brain tumors that originates in the brain itself, in a region called the brainstem.

Symptoms

There are a variety of symptoms of medulloblastoma. These include:

• Headaches
• Dizziness
• Poor balance and coordination
• Sluggishness
• Unusual eye movements
• Blurred vision or double vision
• Weakness of the face or droopiness of the face or eyelid
• Weakness or numbness of one side the body
• Loss of consciousness

The symptoms of medulloblastoma can occur due to damage of the cerebellum or pressure on the nearby structures of the brain, such as the brainstem, or as a result of hydrocephalus (excess fluid pressure in the brain).

Origin

A medulloblastoma originates in the cerebellum, located in a region of the skull described as the posterior fossa. This region includes not only the cerebellum but also the brainstem.

The cerebellum controls balance and coordination and is located behind the brainstem. The brainstem includes the midbrain, pons, and medulla and allows communication between the brain and the rest of the body as well as controls vital functions such as breathing, swallowing, heart rate and blood pressure.

As the medulloblastoma grows inside the cerebellum, it can compress the pons and/or the medulla causing further neurological symptoms, including double vision, facial weakness, and decreased consciousness. Nearby nerves can also be compressed by a medulloblastoma.

Hydrocephalus

Fluid buildup that produces pressure in the brain is one of the characteristics of medulloblastoma, although not everyone who has medulloblastoma develops hydrocephalus.

The posterior fossa, which is the region where the brainstem and cerebellum are located, is nourished by a special type of fluid called CSF (cerebrospinal fluid), just like the rest of the brain. This fluid flows throughout the space that encloses and surrounds the brain and spinal cord. Under normal conditions, there are not any barriers within this space.

Often, a medulloblastoma physically obstructs the freely flowing cerebrospinal fluid, causing excessive fluid in and around the brain. This is called hydrocephalus. Hydrocephalus can cause head pain, neurological symptoms, and lethargy. Neurological damage may result in permanent cognitive and physical disabilities.

Removal of the excess fluid is often necessary. If the fluid needs to be removed repeatedly, a VP (ventriculoperitoneal) shunt may be needed. A VP shunt is a tube that can be surgically placed in the brain to steadily reduce excess fluid pressure.

Diagnosis

The diagnosis of medulloblastoma relies on several methods, which are generally used in combination.

Even if you have the symptoms that are commonly associated with medulloblastoma, it is very likely that you do not actually have a medulloblastoma- because it is a relatively uncommon disease. However, if you do have any of the symptoms characteristic of medulloblastoma, it is important to see your healthcare provider promptly because the cause could be a medulloblastoma or another serious neurological condition.

• History and physical examination: Your practitioner will likely ask you detailed questions about your complaints. During your medical visit, your healthcare provider will also do a thorough physical examination, as well as a detailed neurological examination. The results of your medical history and physical examination can help in pinpointing the best next steps in evaluation of your problem. 
• Brain imaging: If your history and physical are suggestive of a medulloblastoma, your healthcare provider is likely to order brain imaging studies, such as a brain MRI. A brain MRI can provide a good image of the posterior fossa of the brain, which is the location where a medulloblastoma begins to grow.
• Biopsy: A biopsy is a surgical excision of a growth or tumor for the purpose of looking at the removed tissue under a microscope. The results of a biopsy are used to help determine the next steps. In general, if it turns out that you have a tumor that has characteristics of a medulloblastoma, you are likely to be evaluated for surgical removal of the tumor, not for a biopsy. A biopsy typically only involves removal of a minimal amount of tissue. Generally, if you can safely have surgery, removal of as much of the tumor as possible is recommended.

What to Expect

Medulloblastoma is considered a malignant cancer, which means that it can spread. In general, medulloblastoma spreads throughout the brain and spine, causing neurological symptoms. It rarely spreads to other parts of the body outside the nervous system.

Treatment

There are several methods used to treat medulloblastoma, and they are generally used in combination.

• Surgery: If you or your loved one has medulloblastoma, complete surgical removal of the tumor is recommended. You will need to have brain imaging tests and a pre-operative evaluation prior to surgery.
• Chemotherapy: Chemotherapy consists of powerful medications used to destroy cancer cells. This is intended to eliminate or shrink as much of the tumor as possible, including areas of the tumor that may have spread away from the original tumor. There are many different chemotherapeutic medications, and your healthcare provider will determine the right combination for you based on the microscopic appearance of the tumor, the size of the tumor, how far it has spread, and your age. Chemotherapy can be taken by mouth, IV (intravenously) or intrathecally (injected directly into the nervous system).
• Radiation: Radiation therapy is often used in treatment of cancer, including medulloblastoma. Targeted radiation can be directed to the area of the tumor to help reduce the size and prevent recurrence.

Prognosis

With treatment, the 5-year survival of people who are diagnosed with medulloblastoma varies depending on several factors including:

• Age: Infants under the age of 1 are estimated to have about a 30 percent 5-year survival, while children have a 60-80 percent 5-year survival. Adults are estimated to have about a 50-60 percent 5-year survival, with older adults generally experiencing better recovery and survival than younger adults.
• Size of the tumor: Smaller tumors generally are associated with better outcomes than are larger tumors.
• Tumor spread: Tumors that have not spread beyond the initial location are associated with better outcomes than tumors that have spread.
• Whether the whole tumor could be removed during surgery: If the whole tumor was removed, there is a lower chance of recurrence and a better chance of survival than what is observed when there is still residual tumor remaining after surgery. The reason that a tumor might not be completely removed is that it may be too closely connected with or embedded with a region of the brain that is vital for survival.
• The severity of the tumor based on pathology (examination under a microscope): While a biopsy is not a typical first step when a medulloblastoma is removed, it can be examined with a microscope to look for detailed characteristics, which can help guide decisions about radiation and chemotherapy.

Age Range and Incidence

Medulloblastoma is the most common malignant brain tumor in children, yet it is still fairly uncommon, even in children.

• Children: The typical age of diagnosis ranges between age 5 and age 10, but it can occur in infants and in teenagers. Overall, medulloblastoma is estimated to affect about 4-6 children per million in the United States and Canada, with approximately 500 children diagnosed with medulloblastoma in the United States every year.
• Adults: Medulloblastoma is a relatively rare tumor in adults under the age of 45, and is even less common after that. About one percent of brain tumors in adults are medulloblastoma.

Genetics

Most of the time, medulloblastoma is not associated with any risk factors, including genetics. However, there are a few genetic syndromes that may be associated with an increased incidence of medulloblastoma, including Gorlin syndrome and Turcot syndrome.

A Word From Verywell

If you or your loved one has been diagnosed or treated for a medulloblastoma, it can be a very challenging experience. It can also interfere with normal life activities such as school and work. If you experience a tumor recurrence, you will need to get treatment for the tumor again. This recovery process may take a few years and often includes physical and occupational therapy.

Many children and adults recover from medulloblastoma and gain the ability to live a normal and productive life. Cancer treatment for most tumors is rapidly improving, making the outcome better and the treatment more tolerable.