Glioma Resection Unmasks Eloquent Brain Areas

During functional-based resection under awake conditions of a left frontal isocitrate dehydrogenase-wildtype glioblastoma, the initial intralesional debulking performed to alleviate mass effect unmasked the right hemibody negative motor networks that were identified on the neocortex by direct electric stimulation. As compared with preoperative evaluation, the 3-month postoperative functional magnetic resonance imaging (MRI) confirmed unmasked cortical clusters for the right hemibody that were absent preoperatively using the same functional MRI parameters; language clusters were also better seen. The glioma-induced mass effect can mask eloquent brain areas, and surgical decompression can unmask intraoperatively eloquent brain areas.