MEDICAL ALMIGHTY

What are primary brain tumors?

• Astrocytoma - The tumor arises from star-shaped glial cells called astrocytes. In adults, astrocytomas most often arise in the cerebrum. In children, they occur in the brain stem, the cerebrum, and the cerebellum. A grade III astrocytoma is sometimes called an anaplasticastrocytoma. A grade IV astrocytoma is usually called a glioblastoma multiforme.
  
• Brain stem glioma - The tumor occurs in the lowest part of the brain. Brain stem gliomas most often are diagnosed in young children and middle-aged adults.
  
• Ependymoma - The tumor arises from cells that line the ventricles or the central canal of the spinal cord. They are most commonly found in children and young adults.
  
• Oligodendroglioma - This rare tumor arises from cells that make the fatty substance that covers and protects nerves. These tumors usually occur in the cerebrum. They grow slowly and usually do not spread into surrounding brain tissue. They are most common in middle-aged adults.

• Medulloblastoma - This tumor usually arises in the cerebellum. It is the most common brain tumor in children. It is sometimes called aprimitive neuroectodermal tumor.
  
• Meningioma - This tumor arises in the meninges. It usually grows slowly.
  
• Schwannoma - A tumor that arises from a Schwann cell. These cells line the nerve that controls balance and hearing. This nerve is in the inner ear. The tumor is also called an acoustic neuroma. It occurs most often in adults.
  
• Craniopharyngioma - The tumor grows at the base of the brain, near the pituitary gland. This type of tumor most often occurs in children.
  
• Germ cell tumor of the brain - The tumor arises from a germ cell. Most germ cell tumors that arise in the brain occur in people younger than 30. The most common type of germ cell tumor of the brain is agerminoma.
  
• Pineal region tumor - This rare brain tumor arises in or near thepineal gland. The pineal gland is located between the cerebrum and the cerebellum.

• What are secondary brain tumors?

  When cancer spreads from its original place to another part of the body, the new tumor has the same kind of abnormal cells and the same name as the primary tumor. Cancer that spreads to the brain from another part of the body is different from a primary brain tumor. When cancer cells spread to the brain from another organ (such as the lung or breast), doctors may call the tumor in the brain a secondary tumor or metastatic tumor. Secondary tumors in the brain are far more common than primary brain tumors.

  What causes and who is at risk for brain tumors?

  No one knows the exact causes of brain tumors. Doctors can seldom explain why one person develops a brain tumor and another does not. However, it is clear that brain tumors are not contagious. No one can "catch" the disease from another person.
  Research has shown that people with certainrisk factors are more likely than others to develop a brain tumor. A risk factor is anything that increases a person's chance of developing a disease.
  The following risk factors are associated with an increased chance of developing a primary brain tumor:
  • Being male - In general, brain tumors are more common in males than females. However, meningiomas are more common in females.
    
  • Race - Brain tumors occur more often among white people than among people of other races.
    
  • Age - Most brain tumors are detected in people who are 70 years old or older. However, brain tumors are the second most common cancer in children. (Leukemia is the most common childhood cancer.) Brain tumors are more common in children younger than 8 years old than in older children.
    
  • Family history - People with family members who have gliomas may be more likely to develop this disease.
    
  • Being exposed to radiation or certain chemicals at work:
     
    • Radiation - Workers in the nuclear industry have an increased risk of developing a brain tumor.
      
    • Formaldehyde - Pathologists and embalmers who work withformaldehyde have an increased risk of developing brain cancer. Scientists have not found an increased risk of brain cancer among other types of workers exposed to formaldehyde.
      
    • Vinyl chloride - Workers who make plastics may be exposed to vinyl chloride. This chemical may increase the risk of brain tumors.
      
    • Acrylonitrile - People who make textiles and plastics may be exposed to acrylonitrile. This exposure may increase the risk of brain cancer.
  Scientists are investigating whether cell phones may cause brain tumors. Studies thus far have not found an increased risk of brain tumors among people who use cell phones.
  Scientists also continue to study whether head injuries are a risk factor for brain tumors. So far, these studies have not found an increased risk among people who have had head injuries.
  Most people who have known risk factors do not get brain cancer. On the other hand, many who do get the disease have none of these risk factors. People who think they may be at risk should discuss this concern with their doctor. The doctor may be able to suggest ways to reduce the risk and can plan an appropriate schedule for checkups.