MICROSCOPIC DESCRIPTION: Sections show fragments of a moderately hypercellular astrocytic glioma. Tumour cells show moderate nuclear and cellular pleomorphism. Scattered mitotic figures are identified. There is prominent microvascular proliferation with multi-layering of atypical cells around vessel lumina. Areas of palisaded tumour necrosis are also identified.
Immunohistochemistry results show tumour cells stain:
- GFAP Positive
- Nestin Positive (high)
- NogoA Positive
- IDH-1 R132H Positive (mutated)
- ATRX Negative (mutated)
- MGMT Negative (likely methylated)
- p53 Positive
- p16 CDKN2A Negative
- Topoisomerase labelling index: Approximately 30%.
Today's features, combined with the history of previously diagnosed low-grade glioma with confirmed IDH1 mutation are now consistent with the diagnosis of secondary glioblastoma.