The case illustrates features of gliomatosis, especially spreading along the condensed white matter tracts such as corticospinal tracts and corpus callosum to involve the contralateral hemisphere.

Aggressive features such as areas of necrosis and patchy diffusion restriction suggest a diagnosis of glioblastoma. Areas of diffusion restriction helps to identify ares of high-grade transformation and to discriminate the lesion from the surrounding vasogenic edema.

The biopsy results of only grade III tumor most likely represents under-grading due to sampling bias. 

Glioblastomas have traditionally been divided into primary and secondary; the former arising de novo (90%) without a pre-existing lower grade diffuse astrocytoma and they tend to occur in older individuals, whereas the latter developed from a pre-existing lower grade diffuse astrocytoma (10%), they tend to occur in younger patients, and of uncertain significance, they have a predilection for the frontal lobes.

Anaplastic astrocytomas are WHO grade III lesions, with imaging appearances and prognosis between those of diffuse low-grade astrocytomas (WHO grade II) and glioblastomas (WHO IV). 

Lack of IDH status means this tumor should be regarded as an anaplastic astrocytoma NOS (although glioblastoma is most likely).