Sections of brain tissue cores show a moderately cellular tumour composed of mildly pleomorphic cells containing round to oval, hyperchromatic, vesicular nuclei and inconspicuous nucleoli. Tumour cells demonstrate prominent perineuronal secondary structuring. No mitoses, necrosis or microvascular proliferation are seen.
- GFAP Positive
- Nogo A Negative
- Nestin Positive (low)
- IDH-1 R132H Positive (mutated)
- ATRX Positive (non mutated)
- MGMT Negative
- p53 Negative
- p16 Negative T
- opoisomerase labelling index: Approximately 1-2%.
IDH-1 mutant diffuse glioma, favouring astrocytoma (WHO Grade II). ( Morphologically tumour cells demonstrate astrocytic differentiation however the immunohistochemistry results show absent p53 staining and intact ATRX staining, therefore 1p19q molecular testing is recommended) FISH for chromosome 1p/19q deletion.
Results: Chromosome 1p/19q co-deletion detected by FISH.
FINAL DIAGNOSIS: Oligodendroglioma IDH mutant chromosome 1p/19q co-deleted (WHO Grade II).