This case was pathologically proven to be a GBM and the imaging features illustrate a multifocal disease, where multiple areas of enhancement are connected to each other by abnormal white matter signal (T2/FLAIR), which represents microscopic spread to tumor cells. Furthermore, there is involvement of the corpus callosum (see also butterfly glioma).

Callosal lesions, are typically aggressive as the corpus callosum is composed of very dense white matter tracts which acts as a barrier to tumor spreading. 

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.