Brain Tumor (cont.)

There are many types of primary brain tumors. Primary brain tumors are named according to the type of cells or the part of the brain in which they begin. For example, most primary brain tumors begin in glial cells. This type of tumor is called a glioma.

Among adults, the most common types are:

• Astrocytoma: The tumor arises from star-shaped glial cells called astrocytes. It can be any grade. In adults, an astrocytoma most often arises in the cerebrum.
  • Grade I or II astrocytoma: It may be called a low-grade glioma.
  • Grade III astrocytoma: It's sometimes called a high-grade or an anaplastic astrocytoma.
  • Grade IV astrocytoma: It may be called a glioblastoma or malignant astrocytic glioma.
• Meningioma: The tumor arises in the meninges. It can be grade I, II, or III. It's usually benign (grade I) and grows slowly.
• Oligodendroglioma: The tumor arises from cells that make the fatty substance that covers and protects nerves. It usually occurs in the cerebrum. It's most common in middle-aged adults. It can be grade II or III.

Among children, the most common types are:

• Medulloblastoma: The tumor usually arises in the cerebellum. It's sometimes called a primitive neuroectodermal tumor. It is grade IV.
• Grade I or II astrocytoma: In children, this lowgrade tumor occurs anywhere in the brain. The most common astrocytoma among children is juvenile pilocytic astrocytoma. It's grade I.
• Ependymoma: The tumor arises from cells that line the ventricles or the central canal of the spinal cord. It's most commonly found in children and young adults. It can be grade I, II, or III.
• Brain stem glioma: The tumor occurs in the lowest part of the brain. It can be a low-grade or high-grade tumor. The most common type is diffuse intrinsic pontine glioma.

Source: MedicineNet.com
http://www.medicinenet.com/brain_tumor/article.htm