Medulloblastoma are types of tumors, which represent approximately 20 percent of childhood brain tumors, are thought to arise from undeveloped stem cells of the cerebellum, located near the middle of the back of the head. The cerebellum controls balance, posture and movement.
Gliomas represent 84 percent of all brain tumors. A common form of primary brain tumor, gliomas arise from cells called glial cells that surround and support the neurons of the brain. There are three types of glial cells, further distinguished as astrocytes, oligodendrocytes, and ependymal cells.
Types of Gliomas:
- Astrocytoma – The most common form of gliomas, these are tumors in the glial cells called astrocytes, star-shaped cells in the brain and spinal cord that support neurons and help remove debris. Astrocytomas account for nearly half of all childhood brain tumors and arise in the first decade of life, with the peak age at 5-9 years. They are usually slow-growing tumors that cause swelling particularly in the area behind the eyes. Astrocytomas include a variety of sub-divisions: pilocytic astrocytoma, diffuse astrocytoma, anaplastic astrocytoma and glioblastoma multiforme.
- Brainstem Glioma – Originating in the brain or spinal cord tissue, these tumors typically spread throughout the nervous system. Approximately 75 percent are diagnosed in those under age 20. Brainstem gliomas are often primary brain tumors, and rarely metastasize (i.e. spread) to impact another part of the body.
- Optic Glioma – These types of tumors can occur on one or both of the optic nerves, or on the area of the hypothalamus where the optic nerves cross each other (optic chiasm). Optic gliomas are slow-growing, usually benign and are often associated with Type 1 Neurofibromatosis.
- Ependymoma – This is a type of glioma which originates from tissue of the central nervous system called the ependyma. Ependymomas are made up of malignant cancer cells which, in the pediatric variety, form in the brain and the spinal cord. Classified as either supratentorial (in the top part of the head) or infratentorial (in the back of the head), the majority of pediatric ependymomas occur as infratentorial tumors located in or around the fluid-filled fourth cranial ventricle. Ependymomas may are also be associated with Type 2 Neurofibromatosis.
Neurofibromatosis is a syndrome of an abnormality in a gene that leads to tumors. This condition, which affects the nervous system, causes tumors to grow on nerves. It can either be a genetic disorder or a genetic mutation. The tumors are usually benign and grow on nerves, as well as on and under the skin. Type 1 neurofibromatosis (NF1), which can present symptoms as early as at birth, can affect the skin, bones and brain. Type 2 neurofibromatosis (NF2) frequently starts in the teenage years, and causes poor balance, ringing in the ears and hearing loss.
Craniopharyngioma comprise 8.4% of childhood tumors. A craniopharyngioma is a benign tumor that develops near the pituitary gland (a small endocrine gland at the base of the brain). Craniopharyngiomas are typically very slow-growing tumors. At ANA, we use a relatively new, innovative and less invasive surgical approach called the endonasal endoscopy to treat these types of tumors.
Pineal region tumors
The pineal gland is a small gland located in the back of the base of the brain. Although its purpose is not entirely understood, it is known to create the hormones melatonin and serotonin. The most common type of these tumors in this region are germ cell tumors, which arise from developmental abnormalities, and pineal cell tumors, which arise from normal cells of the pineal gland itself.