World Health Organization grading of primary brain tumours
Grade 1
Low grade glioma
Pilocytic astrocytoma Occur most commonly
in children
Grade 2
Low grade glioma
Astrocytoma
Oligodendroglioma
Incidence is
approximately 16-20%
Grade 3
High grade glioma
Anaplastic astrocytoma
Anaplastic
oligodendroglioma
Incidence is
approximately 30%
Grade 4
High grade glioma
Glioblastoma Incidence is
approximately 50%