Neurological Involvement in Pediatric Patients with Acute Leukemia: A Retrospective Cohort.

Acute leukemia (AL) is an important cause of morbidity and mortality in children, and neurological manifestations (NM) are frequent. The objective of this study was to analyze neurological manifestations in children with acute leukemia from cases attended in the last five years at the Centro Médico Nacional "20 de Noviembre". METHODS: Conducting a retrospective and analytical study from 1 January 2015 to 31 December 2020 in children with AL classified according to sex, age range and AL type. Participants were grouped according the presence of NM. RESULTS: We analyzed 607 patients: 54.85% boys and 44.14% girls, with a mean age of 7.27 ± 4.54 years. When comparing groups, the NM group was significantly older (p = 0.01), and the highest prevalence was between 6 and 12 years old. ALL was predominant over the other lineages (p ≤ 0.01). The most frequent NM was CNS infiltration, seizures, headache and neuropathy. Death outcomes occurred in 18.7% of children with AML, 11.8% with ALL and 50% with MPAL (p ≤ 0.002). The NM group was associated with higher mortality during a follow-up time of 77.9 ± 49 months (44.4% vs. 8.9% deaths, NM vs. non-NM, respectively; OR = 3.3; 95% CI 2.4 to 4.6; p ≤ 0.0001). CONCLUSIONS: ALL was the most prevalent leukemia type. CNS infiltration, seizures, headache, neuropathy and PRES were the most frequent symptoms in the NM group. NM was associated with a higher mortality rate.

Visual Mapping for Tumor Resection: A Proof of Concept of a New Intraoperative Task and A Systematic Review of the Literature.

Homonymous hemianopia has been reported after brain tumor resection with a significant effect on quality of life. Nevertheless, no standardized methods exist for intraoperative optical radiation mapping. The purpose of this article is to describe a new intraoperative task for visual mapping and to review the existing literature. A Central and Peripheral Image task was used to map optic radiations during brain tumor resection in 3 patients. A systematic review was performed following PRISMA 2020 guidelines, with 25 of 449 articles included. Optic radiations were identified in all patients and preserved in all but one, in whom the extent of resection prevailed. The literature review exposed 2 methods to assess visual function: visual evoked potentials (VEP) and direct electric stimulation (DES), with 13 and 12 articles and 341 and 63 patients, respectively. Hemianopia was developed in 13.49% of patients with VEP versus 1.59% of patients with DES. The use of DES might be associated with a better outcome (level IV evidence). However, standardization of intraoperative tasks during DES could be improved. In this context, the Central and Peripheral Image task might be an adequate tool for the resection of tumors affecting the optic radiations.

Neurological Manifestations in Pediatric Patients Hospitalized for COVID-19: Experiences of the National Medical Center "20 de Noviembre" in Mexico City.

COVID-19 has affected millions of children and, while it was previously considered as a respiratory disease, neurologic involvement has also been documented. The objective of this study was to identify the neurological manifestations (NMs) and the outcomes of children with COVID-19 who attended the National Medical Center "20 de Noviembre". METHODS: A retrospective cohort study of children hospitalized for COVID-19 from April 2020 to March 2021 was conducted. Clinical-demographic data were registered. Neurologic manifestations were defined as any clinical neurological expression of the central and/or peripheral nervous system that occurred during admission or hospitalization. RESULTS: In total, 46 children with a confirmed COVID-19 result, 26 (56.5%) boys and 20 (43.5%) girls with a median age of 8.9 ± 4.6 years, constituted the study population. Half of the children showed some NMs, and this group of patients concomitantly showed acute lymphoblastic leukemia (ALL, 56%), obesity (17.3%), or acute myeloblastic leukemia (AML, 4.3%). The most frequently described NMs were headache (13, 56%), encephalopathy (10, 43.47%), and epilepsy (4, 17.39%). The mortality rate in children with NMs was 21.7% and they had a higher mortality rate when compared to those without NM p ≤ 0.025. CONCLUSIONS: NMs occurred predominantly in male children aged 6 to 12 years; ALL was the most frequent comorbidity. Headache prevailed and hypoxemia, hypocalcemia, elevated ferritin, and C-reactive protein were associated with NM. Finally, NMs were a risk factor for mortality.

Preoperative breast magnetic resonance imaging in patients with ductal carcinoma in situ: a systematic review for the European Commission Initiative on Breast Cancer (ECIBC).

OBJECTIVE: To evaluate the impact of preoperative MRI in the management of Ductal carcinoma in situ (DCIS). METHODS: We searched the PubMed, EMBASE and Cochrane Library databases to identify randomised clinical trials (RCTs) or cohort studies assessing the impact of preoperative breast MRI in surgical outcomes, treatment change or loco-regional recurrence. We provided pooled estimates for odds ratios (OR), relative risks (RR) and proportions and assessed the certainty of the evidence using the GRADE approach. RESULTS: We included 3 RCTs and 23 observational cohorts, corresponding to 20,415 patients. For initial breast-conserving surgery (BCS), the RCTs showed that MRI may result in little to no difference (RR 0.95, 95% CI 0.90 to 1.00) (low certainty); observational studies showed that MRI may have no difference in the odds of re-operation after BCS (OR 0.96; 95% CI 0.36 to 2.61) (low certainty); and uncertain evidence from RCTs suggests little to no difference with respect to total mastectomy rate (RR 0.91; 95% CI 0.65 to 1.27) (very low certainty). We also found that MRI may change the initial treatment plans in 17% (95% CI 12 to 24%) of cases, but with little to no effect on locoregional recurrence (aHR = 1.18; 95% CI 0.79 to 1.76) (very low certainty). CONCLUSION: We found evidence of low to very low certainty which may suggest there is no improvement of surgical outcomes with pre-operative MRI assessment of women with DCIS lesions. There is a need for large rigorously conducted RCTs to evaluate the role of preoperative MRI in this population. KEY POINTS: • Evidence of low to very low certainty may suggest there is no improvement in surgical outcomes with pre-operative MRI. • There is a need for large rigorously conducted RCTs evaluating the role of preoperative MRI to improve treatment planning for DCIS.

Predicting the Extent of Resection in Low-Grade Glioma by Using Intratumoral Tractography to Detect Eloquent Fascicles Within the Tumor.

BACKGROUND: An early maximal safe surgical resection is the current treatment paradigm for low-grade glioma (LGG). Nevertheless, there are no reliable methods to accurately predict the axonal intratumoral eloquent areas and, consequently, to predict the extent of resection. OBJECTIVE: To describe the functional predictive value of eloquent white matter tracts within the tumor by using a pre- and postoperative intratumoral diffusion tensor imaging (DTI) tractography protocol in patients with LGG. METHODS: A preoperative intratumoral DTI-based tractography protocol, using the tumor segmented volume as the only seed region, was used to assess the tracts within the tumor boundaries in 22 consecutive patients with LGG. The reconstructed tracts were correlated with intraoperative electrical stimulation (IES)-based language and motor subcortical mapping findings and the extent of resection was assessed by tumor volumetrics. RESULTS: Identification of intratumoral language and motor tracts significantly predicted eloquent areas within the tumor during the IES mapping: the positive predictive value for the pyramidal tract, the inferior fronto-occipital fasciculus, the arcuate fasciculus and the inferior longitudinal fasciculus positive was 100%, 100%, 33%, and 80%, respectively, whereas negative predictive value was 100% for all of them. The reconstruction of at least one of these tracts within the tumor was significantly associated with a lower extent of resection (67%) as opposed to the extent of resection in the cases with a negative intratumoral tractography (100%) (P < .0001). CONCLUSION: Intratumoral DTI-based tractography is a simple and reliable method, useful in assessing glioma resectability based on the analysis of intratumoral eloquent areas associated with motor and language tracts within the tumor.

Eliciting Smiles and Laughter During Intraoperative Electric Stimulation of the Cingulum: Surgical Scenario.

Laughter has a major role in daily social interactions; consequently, its biologic bases have been previously studied. Nevertheless, its cerebral representation remains unclear. The most accepted hypothesis has postulated that laughter has 2 components: mirth, related to the temporal and frontal neocortical areas, and motor aspect, related to the limbic system and brainstem. Furthermore, in prior studies, laughter has been elicited during electric stimulation with depth electrodes in the supplementary motor area and the cingulum. This Video 1 reports resection of a right superior frontal gyrus diffuse astrocytoma (isocitrate dehydrogenase mutant, World Health Organization grade II) with awake intraoperative electric cortical and subcortical stimulation mapping. Diffusion tensor imaging (DTI) tractography, including all the tracts in relation to the tumor, was obtained preoperatively and postoperatively. Stimulation of the cingulum medially and inferiorly to the tumor elicited a patient's smile and laugh without mirth or merriment. Also, this point correlated with the reconstructed cingulum in the intraoperatively navigated DTI tractography. In conclusion, these findings support the anatomic subdivision of the laughter's mechanism and the role of the cingulum in its motor component. Furthermore, smiles and laughter could be useful functional landmarks to identify the cingulum during subcortical mapping. Although it remains unclear whether pursuing resection beyond this point would have caused permanent postoperative deficits, considering laughter's role in social interaction and other emotion-processing functions associated with the cingulum, in the future it could be potentially considered a functional limit of the resection of intrinsic tumors.

Consenso para el diagnóstico y tratamiento de la esclerosis múltiple en pacientes del ISSSTE / Consensus for the diagnosis and treatment of multiple sclerosis in ISSSTE patients

Resumen: La esclerosis múltiple es una de las principales enfermedades desmielinizantes del sistema nervioso central, que repercute no solo en lo económico, sino también en lo social. El Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE) dispone de la mayor parte de los tratamientos que modifican la evolución de esta enfermedad y para optimizar su uso, un grupo de neurólogos de la institución se reunió para la realización de un documento sobre aspectos generales de diagnóstico y tratamiento denominado Consenso para el Diagnóstico y Tratamiento de la Esclerosis múltiple en pacientes del ISSSTE. El objetivo de este documento es dar recomendaciones de las diferentes alternativas terapéuticas contra la esclerosis múltiple.

Abstract: Multiple sclerosis is one of the main demyelinating diseases of the central nervous system, which impacts not only economically but also socially. The Mexican Institute of Security and Social Services of State Workers (ISSSTE) has most of the disease modifying treatments for this disease and to optimize its use, a group of neurologists from the institution met to make a document on general aspects of diagnosis and treatment called: Consensus for the diagnosis and treatment of multiple sclerosis in ISSSTE patients. The objective of this consensus is to give recommendations on the different therapeutic alternatives against multiple scle- rosis for adults and children.

Mapping visuospatial and self-motion perception functions in the left parietal lobe.

Parietal lobe functions include somesthesia, language, calculation, self-motion perception, and visuospatial awareness. In this video, the authors show the intraoperative mapping of a left parietal lobe for a low-grade glioma resection. Standard sensory and language mapping were performed. Interestingly, by using the "Line Bisection" task, subcortical stimulation of the gyrus angularis was repeatedly associated with ipsilateral spatial neglect, often described in the right parietal lobe. In a similar way, subcortical stimulation in a more posterior point elicited episodes of vertigo, probably due to stimulation of the superior longitudinal fasciculus. Both findings were useful to define the functional limit of the resection. The video can be found here: https://youtu.be/qgGDRW_6u0A .

Intraoperative Identification and Preservation of Verbal Memory in Diffuse Gliomas: A Matched-Pair Cohort Study.

BACKGROUND: Recent glioma surgery series with intraoperative electrical stimulation (IES) language mapping have demonstrated high rates of postoperative memory impairment, raising a question regarding the efficacy of this approach to preserve memory. OBJECTIVE: To evaluate if intraoperative identification and preservation of verbal memory sites with IES mapping in diffuse gliomas in eloquent areas consistently protect patients from long-term postoperative decline in short-term memory. METHODS: A cohort of 16 subjects with diffuse low-grade or anaplastic gliomas that were operated with IES and intraoperative evaluation of language and verbal memory (cohort A) was matched by tumor side, pathology, and radiotherapy with a cohort of 16 subjects that were operated with IES and evaluation of language (cohort B). Detailed neuropsychological assessment was performed before and 6 mo after surgery. RESULTS: Intraoperative memory mapping was a strong predictor of verbal memory prognosis. In cohort A, 4 patients (26.7%) had a decline of at least one of the 4 short-term memory tests evaluated. In cohort B, 11 patients (73.3%) had a decline of at least one of the 4 tests. This difference was statistically significant in multivariate analysis (P = .022; odds ratio = 9.88; 95% confidence interval = 1.39-70.42). CONCLUSION: Verbal memory areas identified intraoperatively with the current paradigm are critically involved in verbal memory, as memory impairment can be significantly reduced by adapting the resection to avoid those memory areas. Incorporation of verbal memory evaluation in stimulation mapping protocols might assist in reducing postoperative sequelae and preserving the patient's quality of life.

Cross-Modal Recruitment of Auditory and Orofacial Areas During Sign Language in a Deaf Subject.

BACKGROUND: Modern sign languages used by deaf people are fully expressive, natural human languages that are perceived visually and produced manually. The literature contains little data concerning human brain organization in conditions of deficient sensory information such as deafness. CASE DESCRIPTION: A deaf-mute patient underwent surgery of a left temporoinsular low-grade glioma. The patient underwent awake surgery with intraoperative electrical stimulation mapping, allowing direct study of the cortical and subcortical organization of sign language. We found a similar distribution of language sites to what has been reported in mapping studies of patients with oral language, including 1) speech perception areas inducing anomias and alexias close to the auditory cortex (at the posterior portion of the superior temporal gyrus and supramarginal gyrus); 2) speech production areas inducing speech arrest (anarthria) at the ventral premotor cortex, close to the lip motor area and away from the hand motor area; and 3) subcortical stimulation-induced semantic paraphasias at the inferior fronto-occipital fasciculus at the temporal isthmus. CONCLUSIONS: The intraoperative setup for sign language mapping with intraoperative electrical stimulation in deaf-mute patients is similar to the setup described in patients with oral language. To elucidate the type of language errors, a sign language interpreter in close interaction with the neuropsychologist is necessary. Sign language is perceived visually and produced manually; however, this case revealed a cross-modal recruitment of auditory and orofacial motor areas.

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.

Dysfunction of an On-X Heart Valve by Pannus.

A 68-year-old woman with a history of previous double-valve replacement with On-X mechanical heart valves presented with clinical, echocardiographic and cardiac catheterization signs of obstruction of the On-X tricuspid heart valve prosthesis. The patient was successfully reoperated, but at surgery the valve was seen to be invaded by an abnormal overgrowth of pannus that blocked one of the leaflets. A small amount of non-obstructive fresh thrombus was also observed. The valve was successfully replaced with a biological heart valve prosthesis. The patient was discharged home, and is doing well four months after the operation, when echocardiography demonstrated normal function in the tricuspid valve. The present case represents the first ever report of pannus formation and subsequent dysfunction in an On-X heart valve, and also the first case of tricuspid valve malfunction and obstruction using this type of heart valve substitute.

Himen imperforado / Imperforate hymen

El himen imperforado es una anomalía obstructiva del tracto genital inferior femenino que se da en menos del 0,1% de los recién nacidos. El hecho de no realizar una exploración ginecológica a adolescentes sintomáticas por pudor conlleva frecuentemente al retraso diagnóstico. Presentamos a una paciente adolescente sin menarquia remitida a urgencias para estudio de dolor abdominal cíclico asociado a una masa abdominal con retención de orina y estreñimiento. La simple inspección de los genitales externos nos permitió realizar el diagnóstico después de 2 años de sintomatología(AU)

Imperforate hymen is an obstructive anomaly of the female reproductive tract which occurs in less than 0.1% of newborns. Not performing an adequate gynecologic physical examination in symptomatic adolescent girls due to embarrassment can often delay its diagnosis. We present the case of an adolescent girl without menarche who was referred to our hospital for cyclic abdominal pain associated with an abdominal mass accompanied by urinary retention and constipation. Examination of her external genitalia allowed rapid diagnosis after a 2-year history of these symptoms(AU)

Cost-utility of maximal safe resection of WHO grade II gliomas within eloquent areas.

BACKGROUND: Despite the growing use of intraoperative electrical stimulation (IES) mapping for resection of WHO grade II gliomas (GIIG) located within eloquent areas, some authors claim that this is a complex, time-consuming and expensive approach, and not well tolerated by patients, so they rely on other mapping techniques. Here we analyze the health related quality of life, direct and indirect costs of surgeries with and without intraoperative electrical stimulation (IES) mapping for resection of GIIG within eloquent areas. METHODS: A cohort of 11 subjects with GIIG within eloquent areas who had IES while awake (group A) was matched by tumor side and location to a cohort of 11 subjects who had general anesthesia without IES (group B). Direct and indirect costs (measured as loss of labor productivity) and utility (measured in quality adjusted life years, QALYs), were compared between groups. RESULTS: Total mean direct costs per patient were $38,662.70 (range $19,950.70 to $61,626.40) in group A, and $32,116.10 (range $22,764.50 to $46,222.50) in group B (p = 0.279). Total mean indirect costs per patient were $10,640.10 (range $3,010.10 to $86,940.70) in group A, and $48,804.70 (range $3,340.10 to $98,400.60) in group B (p = 0.035). Mean costs per QALY were $12,222.30 (range $3,801.10 to $47,422.90) in group A, and $31,927.10 (range $6,642.90 to $64,196.50) in group B (p = 0.023). CONCLUSIONS: Asleep-awake-asleep craniotomies with IES are associated with an increase in direct costs. However, these initial expenses are ultimately offset by medium and long-term costs averted from a decrease in morbidity and preservation of the patient's professional life. The present study emphasizes the importance to switch to an aggressive and safer surgical strategy in GIIG within eloquent areas.

Eficacia y seguridad del mapeo por estimulación eléctrica intraoperatoria para la extirpación de gliomas OMS grado ii y iii en áreas cerebrales elocuentes / Efficacy and safety of intraoperative electrical stimulation mapping for resection of WHO grade ii and iii gliomas within eloquent areas

Fundamento y objetivo: La técnica de mapeo por estimulación eléctrica intraoperatoria (EEI) es cada vez más utilizada para la extirpación de gliomas OMS grado ii (GGII) y iii (GGIII) en áreas elocuentes, pero son muy pocos los estudios que comparan esta técnica con la cirugía convencional (sin EEI). En este trabajo se compara el grado de resección tumoral, las secuelas, el control de la epilepsia y la calidad de vida en 2 series de pacientes operados con y sin mapeo por EEI.Pacientes y método: Se compararon los resultados en 2 series de pacientes operados de GGII y GGIII en áreas elocuentes en el mismo centro. Período A (2004-2009): 17 pacientes operados sin utilizar EEI. Período B (2009-2010): 19 pacientes operados utilizando EEI.Resultados: El porcentaje tumoral extirpado fue del 54,7% en el período A y del 79,9% en el período B (p=0,006). A los 6 meses de la cirugía, 8 pacientes del período A y uno del período B desarrollaron morbilidad neurológica (p=0,015; odds ratio [OR] 16, intervalo de confianza del 95% [IC 95%] 1,7-148,3). Dos pacientes del período A con epilepsia farmacorresistente y 8 del período B mejoraron el control de las crisis epilépticas (p=0,05; OR 42, IC 95% 2,1-825,7). Nueve pacientes del período A y 18 del período B volvieron a la misma situación laboral que antes de la cirugía (p=0,015; OR 16, IC 95% 1,7-148,4).Conclusiones: La comparación entre las cirugías convencional y con mapeo por EEI revela que esta última aumenta el grado de resección tumoral en un 25,2%, reduce el riesgo de secuelas permanentes en un 48,1%, mejora el control de la epilepsia en formas farmacorresistentes y preserva la calidad de vida (AU)

Background and objective: Despite the growing use of intraoperative electrical stimulation (IES) mapping for the resection of WHO grade ii and iii gliomas (GGII and GGIII) in eloquent areas, few studies have compared 2 series with and without IES. The present study compares 2 series of patients operated with and without IES at the same institution, analyzing the extent of resection, neurological morbidity, epilepsy prognosis and quality of life.Patients and methods: The surgical results in 2 series of patients with GGII and GGIII within eloquent were compared. Period A (2004-2009): 17 patients operated without IES. Period B (2009-2010): 19 patients operated with IES. Results: The extent of tumor resection was 54.7% in group A and 79.9% in group B (P=.006). Six months after surgery, neurological morbidity was present in 8 patients of group A and one patient of group B (P=.015; odds ratio [OR] 16, 95% confidence interval [95% CI] 1.7-148.3). Two patients of group A with refractory epilepsy, and 8 patients of group B improved epilepsy control (P=.05; OR 42, 95% CI 2.1-825.7). Nine patients of group A and 18 patients of group B returned to the same socio-professional situation as before surgery (P=.015; OR 16, 95% CI 1.7-148.4). Conclusions: The comparison of IES mapping surgery to conventional surgery revealed that the former enables to: increase in 25.2% the extent of tumor resection, decrease in 48.1% the risk of permanent sequelae, improve epilepsy control and preserve quality of life (AU)

[Efficacy and safety of intraoperative electrical stimulation mapping for resection of WHO grade ii and iii gliomas within eloquent areas]. / Eficacia y seguridad del mapeo por estimulación eléctrica intraoperatoria para la extirpación de gliomas OMS grado ii y iii en áreas cerebrales elocuentes.

BACKGROUND AND OBJECTIVE: Despite the growing use of intraoperative electrical stimulation (IES) mapping for the resection of WHO grade ii and iii gliomas (GGII and GGIII) in eloquent areas, few studies have compared 2 series with and without IES. The present study compares 2 series of patients operated with and without IES at the same institution, analyzing the extent of resection, neurological morbidity, epilepsy prognosis and quality of life. PATIENTS AND METHODS: The surgical results in 2 series of patients with GGII and GGIII within eloquent were compared. Period A (2004-2009): 17 patients operated without IES. Period B (2009-2010): 19 patients operated with IES. RESULTS: The extent of tumor resection was 54.7% in group A and 79.9% in group B (P=.006). Six months after surgery, neurological morbidity was present in 8 patients of group A and one patient of group B (P=.015; odds ratio [OR] 16, 95% confidence interval [95% CI] 1.7-148.3). Two patients of group A with refractory epilepsy, and 8 patients of group B improved epilepsy control (P=.05; OR 42, 95% CI 2.1-825.7). Nine patients of group A and 18 patients of group B returned to the same socio-professional situation as before surgery (P=.015; OR 16, 95% CI 1.7-148.4). CONCLUSIONS: The comparison of IES mapping surgery to conventional surgery revealed that the former enables to: increase in 25.2% the extent of tumor resection, decrease in 48.1% the risk of permanent sequelae, improve epilepsy control and preserve quality of life.

[Controversy in the management of WHO grade II gliomas in eloquent brain areas: recent literature review]. / Controversias en el tratamiento de los gliomas OMS grado II localizados en áreas elocuentes: revisión de la bibliografía reciente.

Recent studies have shown that diffuse grade II gliomas (GGII) located in eloquent brain areas represent over 80% of all GGII. The optimal management of these tumours is still controversial. It has long been considered that surgery is not an option for GGII within eloquent areas, due to the high risk of inducing postoperative sequelae in patients with normal neurological explorations. However, the safety of these surgeries has significantly improved in recent years due to the rapid development of techniques enabling a precise mapping of brain functions. Noninvasive functional neuroimaging techniques have been recently developed, enabling cortical mapping of the entire brain prior to surgical procedures. Such precise data provide a preoperative estimation of the location of eloquent areas in relation to the tumour, which is essential for surgical planning and preoperative assessment of morbidity for various surgical approaches. The intraoperative electrical stimulation (IES) mapping technique consists in the application of a bipolar electrode on the brain tissue, enabling an accurate location of brain functions. This provides unique assistance in GGII resection, as it generates a discrete and transient "virtual" lesion within the eloquent tissue. Tumour removal is then tailored according to functional boundaries in order to optimise the quality of resection and to minimise the risk of postoperative sequelae, preserving quality of life. For patients with a GGII in an eloquent area, the possibility of an early resection should be evaluated by a multidisciplinary neuro-oncology team specialising in the management of such tumours.

[WHO grade II gliomas: review of the current management]. / Gliomas hemisféricos OMS grado II: revisión del manejo actual.

The optimal management of diffuse WHO grade II gliomas (GGII) is still controversial. Some authors propose a long-term radiological follow-up of the tumor, others perform a biopsy and treat only if clinical or radiological signs of progression, finally, others propose an active treatment from diagnosis. There is mounting evidence that suggest that expectant management is no longer optimal, supporting active treatment from diagnosis. In the present work, an extensive review of the recent literature was performed, in order to clarify some of these controversies. Neuroimaging techniques, such as magnetic resonance imaging (MRI), multivoxel spectroscopy or methionine positron emission tomography (PET), give valuable information about the tumor, but lack of sufficient reliability to make a definitive diagnosis of GGII. Stereotactic biopsy leads to misdiagnosis in up to 71% of cases, which has been associated with sampling errors and inter-observer variability due to the small sample obtained. Therefore, it is now considered that a definitive diagnosis of GGII requires a detailed histological analysis of the sample after maximum tumor removal. Despite the lack of class I evidence, there is growing evidence from cohort studies, favoring extensive surgical resection to improve survival and time to tumor degeneration. Surgery is also effective to treat epilepsy, as an improvement in up to 76% of drug-resistant epilepsies has been documented. Consequently, surgery is now considered as a crucial step for diagnosis and treatment of these tumors. Early radiotherapy after surgery lengthens the period without progression but does not affect overall survival, and is related to cognitive disorders that affect quality of life. Hence, this treatment could be deferred until tumor progression.