Tumors can grow almost anywhere in the brain or spinal cord of a child.
About half of all tumors that occur in the central nervous system of children take root in glial cells. These support nerve cells. Tumors in glial cells are called gliomas. Here are some of the most common types of tumors that affect children:
These tumors start in a common type of star-shaped glial cell called an astrocyte. They make up about 10-20% of all brain tumors in children. Astrocytomas often start in the pons. That’s a part of the brain stem that controls breathing and heart rate. These tumors can be benign (not cancerous) or malignant (cancerous). They can form anywhere in the brain or spinal cord.
Astrocytomas usually spread throughout the brain and blend with other tissue. But not all of these tumors behave the same. Some grow fast, and some grow slowly. Not all of them grow into other tissue.
High-grade and intermediate-grade astrocytomas grow and spread quickly. Low-grade astrocytomas tend to grow more slowly.
Pilocytic astrocytomas are low-grade astrocytomas that are responsible for one in five brain tumors in children. They usually start in the cerebellum, which is toward the back of the brain. They can also start in other areas such as the optic nerve, hypothalamus, and brain stem. These are called diffuse intrinsic pontine gliomas (DIPGs).
Primitive Neuroectodermal Tumors
About one in five brain tumors in children are what doctors call primitive neuroectodermal tumors (PNETs). These start in immature central nervous cells (neuroectodermal cells). These tumors are more common in younger children than older ones, and they typically grow quickly.
The most common PNET is a medulloblastoma, which starts in the cerebellum.
Other PNETS include pineoblastomas, which start in the pineal gland. Neuroblastomas start in the brain or spinal cord.
These are tumors in the brain and spinal cord that start in the ependymal cells. These cells line the ventricles in the brain or central canal of the spinal cord. Ependymal cells produce cerebrospinal fluid (CSF).
CSF flows along the canal and through the ventricles. Ependymomas can block the flow of CSF out of the ventricles. This can cause fluid buildup in the brain, a condition called hydrocephalus. When this happens, your doctor will likely have to drain the excess fluid. shunt may be placed iIf fluid continues to accumulate.
About one in 20 brain tumors in children is an ependymoma. They can be fast-growing or slow-growing. If they’re fast-growing, they’re called anaplastic ependymoma. These tumors spread along the CSF pathway but don’t spread into normal brain tissue.
These tumors start just above the pituitary gland and just below the brain. They account for one in 25 childhood brain tumors and are thought to be inherited. That means they run in families.
This rare brain tumor starts in the brain, in glial cells called oligodendrocytes. This tumor tends to be slow-growing but can get into the surrounding tissues.
These start in the Schwann cells that surround and insulate nerves. They tend to be benign. These tumors are rare in children and are usually the result of an inherited condition like neurofibromatosis type 2.
Schwannomas usually form near the cerebellum on a nerve responsible for hearing and balance. These are called vestibular acoustic or vestibular schwannomas.
Choroid Plexus Tumors
These tumors are rare, mostly benign, tumors that start in the ventricles of the brain.
These are made up of more than one type of cell. They can include oligodendrocytes, astrocytes, and ependymal cells.
Mixed Glial and Neuronal Tumors
These are made up of glial and neuronal cells. They tend to affect children and young adults. They include ganglioglioma, pleomorphic xanthoastrocytoma (PXA) and a dysembryoplastic neuroepithelial tumor (DNET).