Neuroplasticity in glioblastoma: there is more to plasticity than just low grade glioma.

Neuroplasticity is well established in low grade glioma patients. Less is known about functional plasticity in glioblastomas. A 56-year-old lady presented with a recurrent speech deficit seventeen months after her initial craniotomy for a language eloquent glioblastoma (GBM). Pre-operative navigated trans-cranial magnetic stimulation (n-TMS) for language mapping, tractography and intra-operative language mapping were performed. During her second admission, preoperative n-TMS revealed positive responses anterior and posterior to the tumour recurrence. Tractography revealed a decrease in the anterior extension of the Arcuate Fasciculus (AF) in the inferior frontal gyrus and a more anterior component of the Frontal-Aslant Tract (FAT) showed anterior to the tumour itself. A second resection was carried out and the patient was discharged with no language deficit for second line treatment with Lomustine. Intraoperatively, speech arrest was found in a new position posterior to the previous surgical cavity and away from tumour recurrence (where speech arrest was previously located). This case report shows language function neuroplasticity in glioblastoma. This is supported by preoperative cortical and subcortical mapping.