The patient went on to have a craniotomy and excision. A glioblastoma (WHO Grade IV) was histologically diagnosed. 

Most basic radiology textbooks teach that the dural tail sign is pathognomonic of an extra-axial dural-based mass. This is simply not the case! Intra-axial cortical lesions can induce dural thickening that manifests as a dural tail. In addition to glioblastoma (as in this case), metastases and other primary tumors (e.g. pleomorphic xanthoastrocytoma) can give this appearance, as well as peripherally located infections.

Note: The diagnosis of glioblastoma IDH wild-type is actually not entirely established in this case as the IDH wild-type status has only been inferred with a negative IDH1 R132H immunohistochemistry. Although it is in principle possible that this is a non-R132H mutation or an IDH2 mutation, in an elderly individual +/-[particularly with unmethylated MGMT] this possibility is remote.