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What Are the Most Common Childhood Brain Tumors?

Posted on Apr 05, 2021

Brain tumors are the most common solid tumor affecting children and adolescents – there are close to 5,000 new tumors every year. On this week’s On Call for All Kids, Luis Rodriguez, M.D., a pediatric neurosurgeon at Johns Hopkins All Children's Hospital, gives parents some insights into childhood brain tumors and when to seek treatment. 

The type of pediatric brain tumor is age dependent. Between ages 0-4, medulloblastomas and other embryonal tumors (arising from fetal cells in the brain) are the most common. Between ages 5-9, the most common tumor tends to be pilocytic astrocytoma. Malignant gliomas are most common in ages 10-15. In ages 15-19, the most common tumors tend to be tumors in the region of the pituitary gland, lesions like craniopharyngiomas and germ cell tumors. 

What is the most common location for pediatric brain tumors?

The most common site for brain tumors in young children, tends to be the posterior fossa, also known as the infratentorial space. This is the area where the cerebellum and brainstem are located in the back of the head. As children age, the number of tumors presenting in the posterior fossa decreases, and the number of tumors in the supratentorial space (where the brain hemispheres are located), increases.  

What are the symptoms that children present with when they have a brain tumor?

Symptoms and presentation depend on the location of the tumor. Young children tend to get infratentorial tumors; these lesions often block the flow of fluid in the brain causing hydrocephalus – too much fluid in the brain, which leads to elevated pressure in the brain. This causes headaches, vomiting and balance problems. Young infants and babies often present with failure to thrive and vomiting. Often these patients present after multiple visits to other specialists, including gastroenterologists, for treatment of continued, unexplained vomiting. Babies who still have a soft spot present, the fontanelle — where the skull bones haven’t fused yet — can present with a pulsatile soft spot due to elevated pressure. 

Tumors that involve the brainstem, often present with cranial nerve deficits – double vision or failure of the eyes to turn together in the same direction, difficulty swallowing, balance and coordination problems, weakness of one side of the face. 

As the children age, the tumors can present in different fashion depending on their location, size, and how aggressive they are. One common presentation is nausea and vomiting from elevated intracranial pressure — either from hydrocephalus or the large size of the tumor; balance and coordination problems for lesions located near or on the brainstem and cerebellum; weakness, numbness or some form of neurological deficit related to the location of the tumor. Older children and adolescents tend to present with worsening headaches and seizures. 

Are brain tumors “cancer”?

Not necessarily. There is a general belief that the word “tumor” means “cancer.” And that is not always true. A tumor is simply a mass of cells that shouldn’t be there. It could be a low grade or benign lesion that maybe just bears watching and observation, to a highly malignant lesion that needs a biopsy and or attempt at surgical removal. A highly malignant lesion is what we call a cancer. The pathologist looks at the tissue under the microscope and obtains detailed genetic studies on the tissue and this helps to determine the degree of aggressiveness and malignancy. 

Who treats brain tumors?

Brain tumors are treated by a team approach. At Johns Hopkins All Children’s Hospital, we have a busy Neuro-Oncology Program. It is comprised of oncologists who specialize in the treatment of tumors affecting the central nervous system, neurologists, pathologists, radiologists, neuropsychologists and neurosurgeons. 

What does the treatment of a brain tumor entail?

Generally, when a child is diagnosed with a brain tumor, he or she has had a Head CT or an MRI performed during medical evaluation for some of the symptoms mentioned above. At the point of initial diagnosis, we, the neurosurgery team, are consulted to evaluate the patient. We complete the evaluation of the patient by obtaining a full brain and spine MRI with and without contrast and planning surgery if indicated.

The goal of surgery is first and foremost to make a diagnosis — determine what type of tumor it is. The second goal of surgery is to try to remove all the lesion while trying to preserve neurological function. Often, we achieve a full removal. Occasionally, there is some tumor left behind. We then review the pathology and determine whether the patient needs a “second look surgery” to attempt a full removal, or whether the lesion is one that can be treated with chemotherapy, or radiation, or simply followed closely. Other lesions are unfortunately, not amenable to removal and all we can do is a biopsy to make the diagnosis. With any tumor, the most important thing really is the pathology — what kind of tumor it is — because it guides further treatment, whether chemotherapy, radiation, surgery or observation. 

Once a tumor diagnosis has been made, all the experts from the Neuro-Oncology Program meet to discuss the best way to proceed forward with treatment or observation. We meet weekly in our Neuro-Oncology Tumor Board to discuss all pertinent brain tumor cases, old and new. 

On Call for All Kids is a weekly series featuring Johns Hopkins All Children's Hospital experts. Visit each Monday for the latest report.

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