They are derived from small, star shaped cells called Astrocytes. These may develop in the brain, cerebellum and spinal cord. While they usually develop in brain hemispheres in adults, they are more commonly in the brain stem in children. A tumor in 3^rd grade is called anaplastic astrocytom, in 4^th grade glioblastome multiforme, in grading system.

This type develops in the area that hypophysis (Pituitary gland) is stated on. They are usually benign but they are sometimes labeled as malign because they damage surrounding tissues.