PMC8326088_01
PMC8326088_02
Cervicothoracic spinal magnetic resonance imaging. (a) Axial and sagittal views of contrast-enhanced T1-weighted with fat suppression demonstrated an intramedullary lesion from C4 to T4. Note the peripheral isointense signal with an irregular central hyperintense component. (b) The lesion was hyperintense on short-time inversion recovery (sagittal slice) and T2-weighted (axial slice) sequences.
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F1
T1-weighted images, with fat suppression technique of the cervicothoracic spinal MRI, demonstrated an intramedullary lesion from the superior endplate of the C4 vertebra to the inferior endplate of the T4 vertebra, with a peripheral isointense signal and an irregular hyperintense central suggesting an intramedullary mass [Figure 1a]. The lesion was hyperintense on short-time inversion recovery and T2-weighted sequences [Figure 1b].
Microsurgery resection of the cervicothoracic tumor. (a) The lesion was located laterally (left side) pushing the dorsal cervical nerve roots (arrow head). (b) Some dorsal nerve roots were removed to allow lesion removal. (c) Tumor dissection included the most lateral aspect. (d) Subarachnoid plane after lateral dissection. (e) The most inferior aspect of the tumor was very attached. Traction and dissection of this part of the tumor cause a significant drop of the intraoperative somatosensory and motor evoked potentials. It was decided to leave some tumor (asterisk). (f) Final aspect of the cavity. The tumor bed was filled with absorbent cellulose hemostatics.
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F2
The lesion consistency was apparently firm, with a good cleavage plane in the superior aspect of the spinal cord [Figure 2a-d]. The dissection was initiated at the tumor interface within the posterolateral region of the spinal cord adjacent to the dorsal root entry zone [Figure 2a]. Therefore, a partial resection was achieved [Figure 2e and f].
Intraoperative neurophysiological monitoring - right side. (a) Demonstration of motor evoked potential (MEP) with stable amplitude and latency at the beginning of the procedure (gray circle). The following muscles were analyzed: deltoid, triceps brachii, abductor pollicis brevis, tibialis anterior, and abductor hallucis. (b) After superior tumor pole removal, there was a MEP drop in the right triceps brachii muscle (green circle). There were no changes in the other muscles MEPs during inferior pole dissection. (c) At the end of the procedure, there was a MEP normalization on the right side (blue circle).
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F3
There was a MEP amplitude decreasing (90%) of the triceps brachii bilaterally and left abductor pollicis brevis after complete removal of the superior tumor pole [Figures 3a-c and  4a-c]. At the end of the procedure, the right triceps brachii muscle MEP amplitude was normalized [Figures 3a-c and  4ac].
Intraoperative neurophysiological monitoring - left side. (a) Demonstration of motor evoked potential (MEP) with stable amplitude and latency at the beginning of the procedure (gray circle). The following muscles were analyzed: deltoid, triceps brachii, abductor pollicis brevis, tibialis anterior, and abductor hallucis. (b) After superior tumor pole removal, there was 90% MEP drop in the left triceps brachii and abductor pollicis brevis (green circle). During inferior resection, there was 89% MEP drop in the left abductor hallucis and the resection was interrupted (green circle). (c) At the end of the procedure, the MEP signal drop in the left triceps brachii and abductor pollicis brevis was maintained (red circle). The left abductor hallucis MEP returned to the baseline (red circle).
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F4
There was a MEP amplitude decreasing (90%) of the triceps brachii bilaterally and left abductor pollicis brevis after complete removal of the superior tumor pole [Figures 3a-c and  4a-c]. During dissection of the inferior tumor pole, there was 89% decreasing of the left abductor hallucis MEP and the resection was interrupted [Figure 4a-c]. At the end of the procedure, the right triceps brachii muscle MEP amplitude was normalized [Figures 3a-c and  4ac].
Histopathological findings - ganglioglioma. Hematoxylin and eosin stain (x400). (a) Neoplastic neurons with Nissl substance aggregated under the cell membrane and irregular distribution. (b) Eosinophilic granular bodies in a fibrillary microcystic matrix.
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F5
These findings supported the diagnosis of ganglioglioma - World Health Organization Grade I [Figure 5a and b].
Comparison between pre- and post-operative cervicothoracic spine magnetic resonance imaging. (a) Preoperative sagittal view of T2-weighted demonstrating an intramedullary lesion from C4 to T4 (red asterisk). (b) Postoperative sagittal view of T2-weighted demonstrating the hyperintense residual cavity and caudal residual tumor (red asterisk).
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F6
Postoperative MRI, performed 5 months after surgery, showed no growth of residual lesion [Figure 6a and b].