Brain Tumors

The central nervous system (CNS) contains the brain and spinal cord. A CNS tumor is an abnormal growth that occurs in any part of this area. CNS tumors are the most common solid tumor of childhood and the second most common pediatric cancer.

Anatomy of the central nervous system

• Frontal lobe: Front of brain. Responsible for our intellect, behavior, personality, short term memory, planning and voluntary motor activity.
• Parietal lobes: Located behind the frontal lobes and above the temporal lobes. They process sensory information
• Temporal lobes: Located at the sides of the brain.  They process speech, language, hearing and memory.
• Occipital lobes: Located in the back of the brain. They process visual information.
• Cerebellum: Located beneath the occipital lobe. Is responsible for balance and the coordination of voluntary movements.
• Pons: Located below the midbrain on the brain stem. Information traveling between the cerebellum and the cerebrum passes through the pons. eye movements are partially controlled by nerves located in the pons.
• Medulla Oblongata: Is located in the lowest portion of the brain stem. This area controls vital functions such as breathing, blood pressure, heart rate, swallowing and vomiting.

Signs and symptoms

Symptoms depend on location of the tumor and its size.  Symptoms may also depend on the age of the child and developmental level.  In general symptoms can include:

• Headaches and vomiting (often in the morning)
  
• Poor school performance
  
• Lethargy
  
• Double vision
  
• Weakness on one side of body
  
• Seizures
  
• Facial weakness
  
• Difficulty with walking, balance and coordination
  

Types of central nervous system tumors

Astrocytoma (low grade) - Are slow growing tumors. Most commonly seen in children is the juvenile pilocytic astrocytoma or JPA. JPAs are graded from I to II. Grade I means it is slow growing, most easily treated and has very little risk of spreading. Grade II can spread and invade surrounding brain. Oligodendrolioma is another type of grade II astrocytoma tumor. 

Astrocytoma (high grade) - 10% of pediatric brain tumors are high-grade astrocytomas. An anaplastic astrocytoma is classified as a grade III tumor. These tumors have the ability to invade surrounding brain tissue and can spread to other parts of the brain or spinal cord. A glioblastoma multiforme is a grade IV tumor. This is the most aggressive of the astrocytomas., with the highest rate of spread into the surrounding brain and through the CSF to other areas of the brain and spinal cord.

Medulloblastoma - Most common type of malignant pediatric tumors. These tumors can spread through the cerebral spinal fluid (CSF). Medulloblastomas are staged according to the amount of tumor removed at initial surgery, the appearance of the cell under the microscope and whether there is evidence of cells spreading through the CSF at diagnosis.

Ependymomas - Account for 9% of all pediatric CNS tumors. They originate from ependymal cells, which are the cells that line the ventricles of the brain and the center of the spinal cord. Ependymomas that occur in the spinal cord are most common in teenagers. Ependymomas are classified according to degree or malignancy of the cells.  

How is it treated?