MICROSCOPIC DESCRIPTION: Sections show a moderately cellular tumour composed of glial cells with round-to-oval nuclei, smooth chromatin and inconspicuous nucleoli. No necrosis or microvascular proliferation is seen. No mitoses are identified.Immunohistochemistry results show tumour cells stain:
- GFAP Positive
- Nestin Positive (low)
- IDH-1 R132H Positive (mutated)
- ATRX Negative (mutated)
- MGMT Negative (likely methylated)
- NogoA Positive (focal)
- p53 Positive
- p16 CDKN2A Positive
Topoisomerase labelling index: Approximately <5%.
The features are of low-grade diffuse astrocytoma, WHO grade II.
DIAGNOSIS: diffuse astrocytoma, WHO grade II.
SUPPLEMENTARY REPORT:
FISH for chromosome 1p/19q deletion.
1p36: NO DELETION DETECTED
19q13.3: NO DELETION DETECTED