Paraffin sections show multiple fragments of a densely hypercellular tumour. Tumour cells have pleomorphic round, oval and angulated hyperchromatic nuclei with fibrillary processes. Moderate numbers of mitotic figures are identified (8 in 20 high power fields). Foci of microvascular proliferation with multilayering of atypical cells around vessel lumena are noted and there are scattered foci of palisaded necrosis. There is patchy microcalcification.
- GFAP: positive
- Nestin: positive (high)
IDH-1 R132H: negative (not mutated)
- ATRX: positive (not mutated)
- p53: positive
- p16 CDKN2A: positive
- MGMT: positive (likely unmethylated)
Topoisomerase labelling index: Approximately 40%.
DIAGNOSIS: Glioblastoma (WHO Grade IV)