In general, brain tumors occur more frequently in children compared to other types of tumors. Medulloblastoma is often discovered between the ages of five and seven. It is usually located in the back of the head and there is a good chance of recovery if it is found in time.
The tumor develops from so-called embryonic, immature cells. It grows from the cerebellum into the surrounding tissue. This is where, for example, the fourth ventricle, a brain chamber adjacent to the cerebellum, is located. This is filled with cerebrospinal fluid, also known as cerebrospinal fluid. The cerebrospinal fluid surrounds the entire brain and has an important buffering function.
If the medulloblastoma grows into the ventricle, it can release cancer cells into the cerebrospinal fluid and spread very quickly. This can lead to the formation of metastases.
These develop primarily in areas that frequently come into contact with the cerebrospinal fluid, such as the meninges.
The causes for the formation of a medulloblastoma are largely unknown. The embryonic, immature cells from which it develops have not yet differentiated. They begin to grow rapidly and in an uncontrolled manner.
There are some genetic changes that are known to be more frequently associated with medulloblastoma. These include, for example, changes in certain chromosomes of the embryonic cells. Children who have undergone radiotherapy for another disease have an increased risk. Radiotherapy, for example in connection with leukemia, can therefore be a risk factor.
A medulloblastoma triggers symptoms at a very early stage because it grows very quickly. This leads to increased intracranial pressure, which triggers unspecific symptoms. These could also be an indication of other diseases. General problems include
In addition, medulloblastoma triggers different symptoms depending on where it has spread. Specific symptoms may include
- Visual disturbances (for example, squinting),
- Sensory disturbances (for example numbness),
- Balance disorders,
- coordination problems,
- signs of paralysis,
- changes in character.
In addition to the normal medical examination, imaging procedures are particularly important for the detection of a medulloblastoma. These provide an image of the brain and can thus provide information about the size, location and spread of the medulloblastoma.
Magnetic resonance imaging(MRI) is particularly helpful for this. Using MRI, doctors can examine part or all of the patient's body. An MRI can therefore also provide information on whether the medulloblastoma has already spread.
The duration of the examination can vary from a few minutes to over an hour. For the examination, the patient is moved into the tomograph on a mobile couch. It resembles a large tube.
The MRI uses magnetism and therefore does not require X-rays. Hydrogen atoms are the smallest particles in our body. They can be influenced by a strong magnet, for example during an MRI scan.
The concentration of hydrogen atoms varies depending on the tissue layer, which is why they can be easily distinguished from one another. As the brain contains a particularly large number of hydrogen atoms, it can be imaged very well. Tumor tissue can also usually be easily distinguished from healthy tissue, as it has a different hydrogen content.
Another important part of the examination is the lumbar puncture. This involves taking a sample of the cerebrospinal fluid from the spinal column using a hollow needle. This is then examined in the laboratory for cancer cells, as the cerebrospinal fluid often comes into contact with the tumor.

Magnetic resonance imaging (MRI) is an important diagnostic method for medulloblastoma © romaset | AdobeStock
Because a medulloblastoma grows so quickly, rapid and intensive therapy is necessary. Surgical removal is particularly important for treatment. Surgeons attempt to remove the entire tumor. However, this is not always possible as it may have already grown into the surrounding tissue.
In these cases, the operation is immediately followed by further therapy. This can also be used to first reduce the size of the tumor and then remove it completely.
The subsequent therapy also depends on the age of the affected child.
From around three to five years of age, children receive radiation therapy, also known as radiotherapy. This involves treating the affected area with ionizing radiation, such as X-rays or electrons.
The radiation prevents the tumor from dividing so that the cells gradually die off. This also serves to kill cancer cells in the cerebrospinal fluid and prevent them from spreading further.
However, radiotherapy can lead to developmental disorders in young children, for example, which is why it is not used there.
Young children usually receive chemotherapy instead of radiotherapy. This involves the use of certain drugs known as cytostatics. These contain active substances that inhibit further growth of the tumor.
However, the active ingredients in the cytostatic drugs also attack healthy cells. This is why side effects such as hair loss, nausea and vomiting can occur during treatment.
Medulloblastoma can recur even after complete removal if individual cancer cells remain in the body. Good aftercare and regular check-ups are therefore particularly important in order to detect a recurrence as early as possible.
In this case, the same treatment can be given as when the tumor first appeared. Recurrences usually occur in the first three years after successful treatment.