Glial tumor is a general term for numerous tumors of the central nervous system, including astrocytomas, ependymal tumors, Oligodendroglioma, and primitive neuroectodermal tumors. The World Health Organization (WHO) classifies tumors into different categories according to severity and recurrence. The first tumor classified as grade I is called pilocytic astrocytoma and it is most commonly observed in children rather than adults. The next tumor is never common in the Dns called diffuse astrocytoma and it is considered a grade II, they are benign, or noncancerous, but can become malignant, meaning cancerous, as the tumor progresses. Grades III and grade IV are considered malignant astrocytomas. Anaplastic astrocytomas are considered by the WHO to be a grade III astrocytoma and Glioblastoma is a grade IV both are referred to high-grade glial tumors.