The patient went on to have surgery confirming an anaplastic astrocytic tumor. 

Histology

Neoplastic cells are positive for GFAP (polyclonal) and P53.

Ki-67 showed nuclear immunostaining in more than 20% of neoplastic cells.

CD-31 is positive in endothelial cells.

FINAL DIAGNOSIS: High-grade glioma consistent with glioblastoma.

Note: IDH mutation status is not provided in this case and according to the current (2016) WHO classification of CNS tumors, this tumor would, therefore, be designated as a glioblastoma NOS. 

Editorial note: Glioblastomas in this age-group and location, especially appearing so circumscribed, are rare. It is possible, for example, that this actually represents a diffuse midline glioma H3 K27M mutant rather than a glioblastoma. Remembering a saying popularized by Carl Sagan "Extraordinary claims require extraordinary evidence" this case requires additional corroborating evidence. Thus, despite some histological features being reported, the diagnostic certainty of this case has been downgraded to "possible". A complete histological and immunohistochemical report and preferably histological slides are required for the diagnostic certainty to reach "certain".