Recovery of long-term paresis following resection of WHO grade II gliomas infiltrating the pyramidal pathway

Recent publications had reported high rates of preoperative neurological impairments in WHO grade II gliomas (GIIG) that significantly affect the quality of life. Consequently, one step further in the analysis of surgical outcome in GIIG is to evaluate if surgery is capable to improve preoperative deficits. Here are reported two cases of GIIG infiltrating the primary motor cortex and pyramidal pathway that had a long-term paresis before surgery. Both patients were operated with intraoperative electrical stimulation mapping, with identification and preservation of the primary motor cortex and pyramidal tract. Despite the long-lasting paresis, both cases had a significant improvement of motor function after surgery. Knowledge of this potential recovery before surgery is of major significance for planning the surgical strategy in GIIG. Two possible predictors of motor recovery were analyzed: 1) reconstruction of the corticospinal tract with diffusion tensor imaging tractography is indicative of anatomo-functional integrity, despite tract deviation and infiltration; 2) intraoperative identification of motor response by electrostimulation confirms the presence of an intact peritumoral tract. Thus, resection should stop at this boundary even in cases of long lasting preoperative hemiplegia

A very slow-growing exophytic hemisphere glioma: a case report

Introducción. Los gliomas de bajo grado presentan un patrón de crecimiento característico a través de las fibras de la sustancia blanca. El crecimiento exofítico en gliomas de bajo grado hemisféricos no se ha descrito previamente. Se presenta un caso de glioma hemisférico de lenta progresión y con crecimiento exofítico. Caso clínico. Varón de 55 años, con crisis parciales motoras secundarias a un oligodendroglioma de grado II de la Organización Mundial de la Salud. El tumor infiltraba la circunvolución frontal superior con extensión exofítica que se extendía por encima de la circunvolución precentral. Fue seguido con controles clinicorradiológicos durante 23 años. El análisis de la evolución radiológica del tumor demostraba un crecimiento tumoral lento, con una velocidad de crecimiento de 0,5 mm al año. Durante la exéresis quirúrgica se definió un plano subaracnoideo entre el componente exofítico y la circunvolución precentral, que se encontraba desplazada inferiormente sin infiltración tumoral. La estimulación eléctrica intraoperatoria no evidenció función en el componente exofítico, pero sí en la circunvolución precentral. No se observaron déficits neurológicos postoperatorios. Conclusiones. La velocidad de crecimiento en gliomas de bajo grado se ha estimado en 4-6 mm al año. El tumor que se describe aquí tiene una velocidad de crecimiento de 0,5 mm al año, muy por debajo de esta media. La identificación de la porción exofítica es un paso importante en la planificación preoperatoria. Este componente es más fácil de resecar debido al plano de clivaje subaracnoideo y a la ausencia de función.Introduction. Gliomas are characterized by a infiltrative pattern of growth, with cellular migration along the white matter fiber tracts, exophytic growth in low-grade gliomas has not been described yet. A case of hemispheric glioma with slow growing and an exophytic component is presented. Case report. 55 year-old male, with motor partial seizures. MRI shows a WHO grade II oligodendroglioma infiltrating the superior frontal gyrus with exophytic extension above the precentral gyrus. Clinical and radiological follow-up was performed for 23 years. Volumetric assessment of tumor progression revealed a growth rate of 0.5 mm per year. Surgical dissection revealed that the precentral gyrus was displaced inferiorly by the tumor, and a clear subarachnoid plane separated both structures. Functional areas were not identified within the exophytic component. Postoperative neurological deficits were not observed. Conclusions. The growth rate in low-grade gliomas has been estimated between 4 and 6 mm per year. The tumor described here had a growth rate of 0.5 mm per year, far below this average. Preoperative identification of this exophytic growth pattern is of major significance for surgical planning. The exophytic tumor is amenable for a safe and complete resection as it is covered by the arachnoid and pial membranes of the cistern and the surrounding brai