The patient went on to have an excision. 

Histology

MICROSCOPIC DESCRIPTION:

The sections show evidence of organizing hemorrhage with sheets of foamy macrophages and many intermixed blood vessels. A few other fragments show a densely cellular astrocytic tumor. The tumor cells have elongated, angulated and hyperchromatic nuclei. Scattered mitotic figures are identified. Microvascular proliferation is inconspicuous. Small foci of tumor cell necrosis are seen. The tumor cells are GFAP, p53 and MGMT immunostains positive. The topoisomerase index is about 15%. IDH-1 and melan-A are negative. The features are those of glioblastoma.

FINAL DIAGNOSIS: glioblastoma (WHO Grade IV).

Note: Although this tumor is entirely consistent with IDH wild-type molecular subtype, strictly speaking, to conclusively establish this, IDH would need to be sequenced to ensure that a non-IDH1 R132H mutation was present. In practice, an IDH1 R132H negative tumor in an individual over 55-years-of-age makes the possibility of this being IDH mutant remote (<1%), and sequencing is not felt to be necessary by many institutions, and not recommended by the WHO classification of CNS tumors (2016).