Grading classifies different histological types and also within each type. Arabic numerals (1, 2, 3, 4) are used instead of Roman numbers.
Eg: Astrocytoma, IDH Mutant, CNS WHO Grade 2
Total 4 grades only.
Grade 1
Circumscribed tumours.
- Pilocytic astrocytoma (Well circumscribed)
- Diffuse astrocytoma MYB altered
- Angiocentric glioma
- PLNTY
- Multinodal & vacuolating neuronal tumour
- Subependymoma
- Myxopapillary ependymoma
- Meningioma (most of them except 4 below)
- SFT (can be 1, 2, 3)
- Chordoma
- Ganglioglioma
Grade 2, 3 (3 = anaplastic)
2 = infiltrating.
3 = evidence of malignancy. eg: Anaplastic ependymoma/astrocytoma/oligodendroglioma
- Astrocytoma, IDH Mutant
- Oligodendroglioma, IDH Mutant
- Pleomorphic xanthoastrocytoma
- Chordoid glioma (all mixed gliomas)
- Ependymoma
- Supratentorial, Posterior fossa Ependymoma
- G2 meningiomas: Clear cell, Chordoid, Atypical Meningiomas
- G3 meningiomas: Rhabdoid, Papillary and anaplastic meningioma
- Central neurocytoma
- Hemangiopericytoma
Grade 4
Malignant, aggressive, rapid growth and necrosis.
- Glioblastoma, Gliosarcoma
- Diffuse midline and diffuse hemispheric glioma
- All “-blastomas”.
- Medullo, Pinealo, Ependymo-
- Atypical teratoid / rhabdoid tumour