Pediatric Brain Tumors
Brain and spinal cord tumors -- known as central nervous system tumors (CNS) -- are the most common type of solid tumor in children, constituting about 20 percent of all malignancies in patients under the age of 15. Brain tumors can be either benign (non-cancerous) or malignant (cancerous). There are many different types of brain tumors. Tumors that form in the tissues and cells of a child's brain are called primary brain tumors. In some cases, tumors that have originated in other parts of the body spread, or metastasize, to the brain.
Forms of Brian Tumors:
1. Astrocytoma/Giloma
Astrocytomas are tumors that arise from brain cells called astrocytes. Gliomas originate from glial cells, most often astrocytes.
Astrocytomas are of two main types—high-grade and low-grade. High-grade tumors grow rapidly and can easily spread through the brain. Low-grade astrocytomas are usually localized and grow slowly over a long period of time. High-grade tumors are much more aggressive and require very intensive therapy. The majority of astrocytic tumors in children are low-grade, whereas the majority in adults are high-grade. These tumors can occur anywhere in the brain and spinal cord.
Common sites in children are the cerebellum (the area just above the back of the neck), cerebral hemispheres (the top part of the brain), and the thalamus or hypothalamus (located in the center of the brain).
Some of the more common low-grade astrocytomas are:
Juvenile Pilocytic Astrocytoma (JPA)
Fibrillary Astrocytoma
Pleomorphic Xantroastrocytoma (PXA)
Desembryoplastic Neuroepithelial Tumor (DNET)
The two most common high-grade astrocytomas are:
Anaplastic Astrocytoma (AA)
Glioblastoma Multiforme (GBM)
2. Ependymomas
Ependymomas arise from cells lining the passageways in the brain that produce and store the cerebrospinal fluid or CSF. (CSF is a fluid that bathes the brain and spinal cord.) These tumors are classified as either supratentorial (in the top part of the head) or infratentorial (in the back of the head). In children, the majority of ependymomas occur as infratentorial tumors arising in or around the fluid-filled fourth ventricle.
3. Medulloblastomas and PNETs
Medulloblastomas are tumors that arise in the posterior fossa region of the brain. The exact cell of origin is not known. These tumors are also referred to as primitive neuroectodermal tumor (PNET). Tumors that have the same characteristics can also arise in other parts of the brain. Representing approximately 15 percent of childhood brain tumors, medulloblastomas are tumors that arise from undeveloped stem cells in the portion of the brain that controls voluntary movement, the cerebellum. They are highly malignant, but with appropriate treatment many children can be cured.
4. Germ Cell Tumors
These tumors arise from various types of "germ cells" found in the brain. Different types of germ cells give rise to different types of tumors, including germinoma, embryonal carcinoma, endodermal sinus tumor and teratoma. These tumors arise primarily in two locations in the center of the brain, the suprasellar and pineal regions. Germ cell tumors commonly malignant.