MICROSCOPIC DESCRIPTION:
The paraffin sections show cores of a moderately hypercellular glial tumour. This consists predominantly of moderately pleomorphic fibrillary astrocytes with a quantitatively smaller population of gemistocytic astrocytic cells. Tumour cells show moderate nuclear pleomorphism. No mitotic figures are identified. There is no vascular endothelial cell hyperplasia and no necrosis is seen.
IMMUNOHISTOCHEMISTRY:
- GFAP positive
- IDH-1 positive (R132H mutated)
- MGMT negative (likely methylated)
- p53 positive p16 positive
- Topoisomerase labelling index: approximately 8%.
FINAL DIAGNOSIS: Diffuse astrocytoma (WHO Grade II) with a gemistocytic component.