The patient went on to have surgery.

Histology

MICROSCOPIC DESCRIPTION: Sections show fragments of a markedly hypercellular astrocytic glioma. Tumor cells show marked nuclear and cellular pleomorphism. Scattered mitotic figures are identified. There is prominent microvascular proliferation with multi-layering of atypical cells around vessel lumena. Extensive areas of palisaded tumor necrosis are also present.

Immunohistochemistry results show tumor cells stain:

• GFAP: Positive
• Nestin: Positive (high)
• NogoA: Negative
• IDH-1 R132H: Negative (non-mutated)
• ATRX: Positive (non-mutated)
• MGMT: Negative (likely methylated)
• p53: Positive
• p16 CDKN2A: Positive
• Topoisomerase labeling index: 20%.
• BRAF: No mutation detected.

Conclusion: Histologically the differential diagnoses include glioblastoma and anaplastic pleomorphic xanthoastrocytoma, however, the absence of a BRAF mutation strongly favors glioblastoma.

FINAL DIAGNOSIS: IDH-1 wild type Glioblastoma (WHO Grade IV).