Factores de riesgo para infecciones del sitio quirúrgico en tumores de fosa posterior / Risk factors for surgical site infections in posterior fossa tumors

Introducción: Los tumores de fosa posterior son la patología oncológica más frecuente en pediatría con la exéresis quirúrgica como principal tratamiento1­3. El hecho de que sea un procedimiento frecuente no hace que se encuentre exento de complicaciones, como infecciones del sitio quirúrgico 4,5. El objetivo principal es conocer los factores de riesgo que se asocian a infecciones del sitio quirúrgico posterior a la exéresis de tumores de fosa posterior en una población completamente pediátrica. Metodología: Se realizó un estudio de casos y controles retrospectivo donde se analizaron todas las cirugías de tumores de fosa posterior que se realizaron en nuestro hospital entre enero del 2014 a mayo del 2020. Se incluyeron como casos a todos los pacientes que presentaron una infección del sistema nervioso central postoperatoria y como controles a los que pacientes que se operaron y no presentaron infección. Resultados: Al analizar los factores de riesgo encontramos que los pacientes con colocación de DVP (p=0.03) o DVE (p=0.005) tienen mayor chance de presentar infección del sitio quirúrgico en el postoperatorio. Mayor valor de Hemoglobina (p=0.002) parecería ser un factor preventivo. Las cirugías prolongadas (p<0.001) y la fístula a través de la herida (p=0.002) aumentan s las chances de infección del sitio quirúrgico en el postoperatorio. Conclusiones: Algunas estrategias que podrían ayudar a reducir el número de infecciones son: un adecuado control de la hidrocefalia prequirúrgica, preferentemente mediante TVE; reducir al mínimo el tiempo quirúrgico necesario para realizar el procedimiento; ingresar a quirófano con una hemoglobina adecuada y evitar la fístula de líquido por la herida

Evolution of transmaxillary approach to tumors in pterygopalatine fossa and infratemporal fossa: anatomic simulation and clinical practice / 中华医学杂志(英文版)

BACKGROUND@#The endoscopic transnasal approach has been proven to have advantages on the removal of the tumors in pterygopalatine fossa (PPF) and infratemporal fossa (ITF). Herein, this study aimed to describe a modified approach for resection of the tumors in these areas, both in cadaveric specimen and clinical patients.@*METHODS@#The 20 adult cadaveric specimens and five patients with tumors in PPF and ITF were enrolled in this study. For the cadaveric specimens, ten were simulated anterior transmaxillary approach and ten were performed modified endoscopic transnasal transmaxillary approach. The exposure areas were compared between two groups and main anatomic structure were measured. Surgery was operated in the five patients with tumors of PPF and ITF to verify the experience from the anatomy. Perioperative management, intraoperative findings and postoperative complications were recorded and analyzed.@*RESULTS@#The modified endoscopic transnasal transmaxillary approach provided as enough surgical exposure and high operability to the PPF and ITF as the anterior transmaxillary approach did. The diameter of maxillary artery in the PPF was 3.77 ± 0.78 mm (range: 2.06-4.82 mm), the diameter of middle meningeal artery in the ITF was 2.79 ± 0.61 mm (range: 1.54-3.78 mm). Four patients who suffered schwannoma got total removal and one of adenocystic carcinoma got subtotal removal. The main complications were facial numbness and pericoronitis of the wisdom tooth. No permanent complication was found.@*CONCLUSIONS@#With the widespread use of neuroendoscopy, the modified endoscopic transnasal transmaxillary approach is feasible and effective for the resection of tumors located in PPF and ITF, which has significant advantages on less trauma and complications to the patients.

Abordaje endoscópico al cavum de Meckel: resección endoscópica endonasal de schwannoma del nervio trigémino / Endoscopic approach to the Meckel's cave: endonasal endoscopic resection of a trigeminal schwannoma

RESUMEN El cavum de Meckel (CM) es un divertículo localizado en la fosa media adyacente al seno cavernoso. Las neoplasias de esta región son extremadamente raras y representan un desafío para el cirujano debido a las estructuras neurovasculares que se encuentran en la región. Para los tumores ubicados en esta área se han descrito diversos abordajes quirúrgicos, los cuales no logran una adecuada exposición a la porción anteromedial del CM. En la última década, se ha postulado el abordaje endoscópico endonasal extendido (AEE) como una alternativa quirúrgica para el manejo de lesiones ubicadas en esta región. Se presenta el caso de un paciente portador de un schwannoma del nervio trigémino situado en el CM derecho tratado mediante AEE.

ABSTRACT The Meckel's cave (CM) is a diverticulum located in the middle fossa adjacent to the cavernous sinus. The neoplasms of this region are extremely rare and represent a challenge for the surgeon due to the neurovascular structures that occupy and surround the parasellar region. For tumors located in this area, several surgical approaches have been described, all of which do not achieve an adequate exposure to the anteromedial portion of CM. In the last decade, the extended endonasal endoscopic approach (EEA) has been postulated as an alternative for the surgical management of tumors located in this region. We present the case of a patient with a trigeminal schwannoma located in the right CM treated by EEA.

Intraoperative Neurophysiological Monitoring : A Review of Techniques Used for Brain Tumor Surgery in Children

Intraoperative monitoring (IOM) utilizes electrophysiological techniques as a surrogate test and evaluation of nervous function while a patient is under general anesthesia. They are increasingly used for procedures, both surgical and endovascular, to avoid injury during an operation, examine neurological tissue to guide the surgery, or to test electrophysiological function to allow for more complete resection or corrections. The application of IOM during pediatric brain tumor resections encompasses a unique set of technical issues. First, obtaining stable and reliable responses in children of different ages requires detailed understanding of normal ageadjusted brain-spine development. Neurophysiology, anatomy, and anthropometry of children are different from those of adults. Second, monitoring of the brain may include risk to eloquent functions and cranial nerve functions that are difficult with the usual neurophysiological techniques. Third, interpretation of signal change requires unique sets of normative values specific for children of that age. Fourth, tumor resection involves multiple considerations including defining tumor type, size, location, pathophysiology that might require maximal removal of lesion or minimal intervention. IOM techniques can be divided into monitoring and mapping. Mapping involves identification of specific neural structures to avoid or minimize injury. Monitoring is continuous acquisition of neural signals to determine the integrity of the full longitudinal path of the neural system of interest. Motor evoked potentials and somatosensory evoked potentials are representative methodologies for monitoring. Free-running electromyography is also used to monitor irritation or damage to the motor nerves in the lower motor neuron level : cranial nerves, roots, and peripheral nerves. For the surgery of infratentorial tumors, in addition to free-running electromyography of the bulbar muscles, brainstem auditory evoked potentials or corticobulbar motor evoked potentials could be combined to prevent injury of the cranial nerves or nucleus. IOM for cerebral tumors can adopt direct cortical stimulation or direct subcortical stimulation to map the corticospinal pathways in the vicinity of lesion. IOM is a diagnostic as well as interventional tool for neurosurgery. To prove clinical evidence of it is not simple. Randomized controlled prospective studies may not be possible due to ethical reasons. However, prospective longitudinal studies confirming prognostic value of IOM are available. Furthermore, oncological outcome has also been shown to be superior in some brain tumors, with IOM. New methodologies of IOM are being developed and clinically applied. This review establishes a composite view of techniques used today, noting differences between adult and pediatric monitoring.

Intraoperative Neurophysiological Monitoring : A Review of Techniques Used for Brain Tumor Surgery in Children

Intraoperative monitoring (IOM) utilizes electrophysiological techniques as a surrogate test and evaluation of nervous function while a patient is under general anesthesia. They are increasingly used for procedures, both surgical and endovascular, to avoid injury during an operation, examine neurological tissue to guide the surgery, or to test electrophysiological function to allow for more complete resection or corrections. The application of IOM during pediatric brain tumor resections encompasses a unique set of technical issues. First, obtaining stable and reliable responses in children of different ages requires detailed understanding of normal ageadjusted brain-spine development. Neurophysiology, anatomy, and anthropometry of children are different from those of adults. Second, monitoring of the brain may include risk to eloquent functions and cranial nerve functions that are difficult with the usual neurophysiological techniques. Third, interpretation of signal change requires unique sets of normative values specific for children of that age. Fourth, tumor resection involves multiple considerations including defining tumor type, size, location, pathophysiology that might require maximal removal of lesion or minimal intervention. IOM techniques can be divided into monitoring and mapping. Mapping involves identification of specific neural structures to avoid or minimize injury. Monitoring is continuous acquisition of neural signals to determine the integrity of the full longitudinal path of the neural system of interest. Motor evoked potentials and somatosensory evoked potentials are representative methodologies for monitoring. Free-running electromyography is also used to monitor irritation or damage to the motor nerves in the lower motor neuron level : cranial nerves, roots, and peripheral nerves. For the surgery of infratentorial tumors, in addition to free-running electromyography of the bulbar muscles, brainstem auditory evoked potentials or corticobulbar motor evoked potentials could be combined to prevent injury of the cranial nerves or nucleus. IOM for cerebral tumors can adopt direct cortical stimulation or direct subcortical stimulation to map the corticospinal pathways in the vicinity of lesion. IOM is a diagnostic as well as interventional tool for neurosurgery. To prove clinical evidence of it is not simple. Randomized controlled prospective studies may not be possible due to ethical reasons. However, prospective longitudinal studies confirming prognostic value of IOM are available. Furthermore, oncological outcome has also been shown to be superior in some brain tumors, with IOM. New methodologies of IOM are being developed and clinically applied. This review establishes a composite view of techniques used today, noting differences between adult and pediatric monitoring.

Intraoperative Monitoring of Hypoglossal Nerve Using Hypoglossal Motor Evoked Potential in Infratentorial Tumor Surgery: A Report of Two Cases

The hypoglossal nerve (CN XII) may be placed at risk during posterior fossa surgeries. The use of intraoperative monitoring (IOM), including the utilization of spontaneous and triggered electromyography (EMG), from tongue muscles innervated by CN XII has been used to reduce these risks. However, there were few reports regarding the intraoperative transcranial motor evoked potential (MEP) of hypoglossal nerve from the tongue muscles. For this reason, we report here two cases of intraoperative hypoglossal MEP monitoring in brain surgery as an indicator of hypoglossal deficits. Although the amplitude of the MEP was reduced in both patients, only in the case 1 whose MEP was disappeared demonstrated the neurological deficits of the hypoglossal nerve. Therefore, the disappearance of the hypoglossal MEP recorded from the tongue, could be considered a predictor of the postoperative hypoglossal nerve deficits.

Tractografía de la vía dento-rubro-talámica en mutismo cerebeloso postoperatorio en niños con tumores de fosa posterior / Analysis of diffusion tensor imaging tractography of the dentate-rubro-thalamic pathway in postoperative cerebellar mutism in children with posterior fossa tumors

Introduction: Cerebellar mutism syndrome refers to the muteness (lack of speech) that follows lesions of the cerebellum. It’s characterized by a late onset, limited duration, and in some cases long-term language sequelae. Its pathogenesis it s not clear yet, but it has been attributed a role to a damage of the dentate nucleus and of the dento-rubro-thalamic tract. Objectives: Identify potential risk factors (clinical or anatomical) to predict the onset of cerebellar mutism after posterior fossa surgery Compare, using MRI analysis and DTI tractography, the integrity of the dento-rubro-thalamic tract in patients with and without cerebellar mutism. Methods: Prospective follow up study of patients operated of posterior fossa tumors between November 2012 and 2013. We performed a study with DTI of the dento rubro thalamic tract in pacients with and without postoperative mutism. Results: 53 patients under the diagnosis of posterior fossa tumor underwent surgical resection. 5 pacients presented postoperative mutism (9,4 percent). There was a significant association between postoperative medulloblastoma diagnosis and postoperative mutism. Tumor volume was not significant. The volume of left and right dento rubro thalamic tract were significantly lower in patients with cerebellar mutism. The fractional anisotropy of the right superior cerebellar peduncle was also lower in patients with postoperative mutism. Conclusions: The postoperative cerebellar mutism is a relevant complication after a posterior fossa surgery. Our study supports the role of dento rubro thalamic tract damage in the pathogenesis of this syndrome. Special care must be taken during surgery to prevent damage to this tract.

Introducción: El síndrome mutismo cerebeloso consiste en falta del habla posterior a lesiones del cerebelo. Se caracteriza por inicio tardío, duración limitada, y ocasionalmente secuelas lingüísticas. Su patogenia no está clara, pero se ha atribuido un rol a daños en el núcleo dentado y en la vía dento-rubro-talámica. Objetivos: Identificar posibles factores de riesgo (clínicos o anatómicos) asociados a la aparición de mutismo cerebeloso después de una cirugía de fosa posterior. Comparar, mediante un análisis de resonancia magnética (IRM) y tractografía por tensor de difusión (DTI), la integridad de la vía dento-rubro-talámica en pacientes con y sin mutismo cerebeloso. Métodos: Estudio prospectivo de pacientes operados por tumores de fosa posterior entre noviembre de 2012 y 2013. Se analizó con DTI la vía dento-rubro-talámica en pacientes con y sin mutismo postoperatorio. Se comparó la volumetría del tracto en ambas cohortes. Resultados: Cincuenta y tres pacientes con diagnóstico de tumor de fosa posterior fueron sometidos a cirugía de exéresis. Cinco pacientes presentaron mutismo postoperatorio (9,4 por ciento). Hubo una asociación significativa entre el diagnóstico de meduloblastoma y mutismo postoperatorio. El volumen tumoral no fue significativo. El volumen de la vía dento-rubro-talámica fue significativamente menor en pacientes con mutismo, en forma bilateral, así como la anisotropía fraccional del pedúnculo cerebeloso derecho. Conclusiones: El mutismo cerebeloso es una complicación relevante después de una cirugía de fosa posterior. Nuestro estudio apoya el papel del daño de la vía dento-rubro-talámica en la patogénesis de este síndrome. Se debe tener especial cuidado durante la cirugía para prevenir daños al núcleo dentado.

Análise de sobrevida de pacientes portadores de tumores do sistema nervoso central / Survival analysis of patients with central nervous tumor

Objetivos: analisar a sobrevida de pacientes com diagnóstico de tumores do sistema nervoso central (SNC) em um serviço de referência em Oncologia Pediátrica, sua apresentação clínica, evolução e influência de fatores prognósticos. Métodos: estudo de coorte histórica. Foram estudados pacientes menores de 19 anos, no período de março de 2003 a dezembro de 2009. O método de Kaplan-Meier foi utilizado para estimar a probabilidade de sobrevida global (SGLO). O teste de log rank e o modelo de regressão de Cox foram usados nas análises univariada e multivariada. Resultados: foram incluídos 159 pacientes, com mediana de tempo de seguimento de 13 meses. O intervalo entre o início dos sintomas e o diagnóstico teve mediana de 1,9 mês; 52% eram do gênero masculino. A mediana de idade ao diagnóstico foi de 7,2 anos. Os diagnósticos histológicos mais frequentes foram glioma de baixo grau (27%), meduloblastoma (19,5%) e tumor de tronco encefálico (17,6%). Cefaleia foi o sintoma mais frequente ao diagnóstico. A localização primária mais comum dos tumores foi a infratentorial (55,3%). A SGLO aos cinco anos foi de 42% (IC 95, 33 a 53%). Na análise univariada, foi observada associação significativa entre tempo de surgimento dos sintomas e o diagnóstico (p=0,046) e diagnóstico histológico (p<0,001). Na análise multivariada, esses fatores mantiveram-se e foram acrescidos da localização primária do tumor. Discussão: a SGLO observada neste estudo foi claramente inferior às descritas na literatura internacional, porém semelhante à de dois outros centros de referência nacionais. Estudos multicêntricos em nível nacional são necessários para confirmação desses resultados.

Objetives: To evaluate outcome of patients with the diagnosis of Central Nervous System tumors at a local reference pediatric oncology service, their clinical presentation, evolution and influence of prognostic factors. Methods: Patients enrolled in this retrospective study between March,2003 and December,2009, were less than nineteen years old at the time of the diagnosis. Kaplan-Meier method was used to estimate the overall survival (OS). Log rank test and Cox?s method were used in the statistical analysis. Results: Study population consisted of 159 patients with median follow up period of 13 months. Median of the time between onset of symptoms and diagnosis was 1,9 months. Boys comprised 52% of the studied population. Median age at diagnosis was 7,2 years. Most common diagnostic subtypes were low grade glioma (27%), medulloblastoma (19,5%) and brain stem tumors (17,6%). Headache was the most frequent symptom (57%) and infratentorial tumors correspond to 55,3% of the cases. An estimated OS of 42% (CI 95%, 33% to 53%) was observed for the role group. An association between outcome and the following variables was observed: interval between the time of onset of symptoms and diagnosis (p=0,046)and histological classification of the tumors (p<0,001). In the multivariate analysis, these variables were sustained, added of the primary location of the tumor in the Central Nervous System. Discussion: Overall survival detected in this study was clearly worse when compared with international centers rates, although were similar to other Brazilian studies. It?s important to develop multicentric studies to confirm data showed in this study

Patterns of Failure Following Multimodal Treatment for Medulloblastoma: Long-Term Follow-up Results at a Single Institution / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The purpose of this study is to investigate the long-term results and appropriateness of radiation therapy (RT) for medulloblastoma (MB) at a single institution. MATERIALS AND METHODS: We analyzed the clinical outcomes of 106 patients with MB who received RT between January 1992 and October 2009. The median age was 7 years (range, 0 to 50 years), and the proportion of M0, M1, M2, and M3 stages was 60.4%, 8.5%, 4.7%, and 22.6%, respectively. The median total craniospinal irradiation (CSI) and posterior fossa tumor bed dose in 102 patients (96.2%) treated with CSI was 36 Gy and 54 Gy, respectively. RESULTS: The median follow-up period in survivors was 132 months (range, 31 to 248 months). A gradual improvement in survival outcomes was observed, with 5-year overall survival rates of 61.5% in 1990s increasing to 73.6% in 2000s. A total of 29 recurrences (27.4%) developed at the following sites: five (17.2%) in the tumor bed; five (17.2%) in the posterior fossa other than the tumor bed; nine (31%) in the supratentorium; and six (20.7%) in the spinal subarachnoid space only. The four remaining patients showed multiple site recurrences. Among 12 supratentorial recurrences, five cases recurred in the subfrontal areas. Although the frequency of posterior fossa/tumor bed recurrences was significantly high among patients treated with subtotal resection, other site (other intracranial/spinal) recurrences were more common among patients treated with gross tumor removal (p=0.016). There was no case of spinal subarachnoid space relapse from desmoplastic/extensive nodular histological subtypes. CONCLUSION: Long-term follow-up results and patterns of failure confirmed the importance of optimal RT dose and field arrangement. More tailored multimodal strategies and proper CSI technique may be the cornerstones for improving treatment outcomes in MB patients.

Estudio neuropsicológico pre y posquirúrgico en dos niños de 8 años de edad con tumor en fosa posterior / Neuropsychological study pre and post surgical in two children aged 8 years with posterior fossa tumor

Objetivo: Identificar y describir las diferencias neuropsicológicas antes y después de resecar el tumor en 2 pacientes de 8 años de edad con una neoplasia en la fosa posterior. Metodología: Se realizó evaluación neuropsicológica pre y posquirúrgica a 2 pacientes de 8 años de edad del Instituto Nacional de Pediatría, uno femenino con quiste aracnoideo en cisterna paravermiana y otro masculino con meduloblastoma en vermis y se compararon los datos obtenidos antes de extirpación de tumor y después de ella. Para la obtención del IQ se aplicó el WISC-IV y para las otras funciones, la Evaluación Neuropsicológica Infantil (ENI), para niños de 5 a 16 años, obteniéndose sus valores en percentiles que se igualaron con la clasificación cualitativa. Resultados: Los 2 pacientes presentaron deficiencias en el IQ, en Funciones Cognitivas, en las Habilidades de Rendimiento Académico, así como en sus Funciones Ejecutivas. A pesar de que no se aplicó quimioterapia ni radioterapia, tanto antes de la cirugía, como después de la extirpación del tumor, empeorando dichas funciones después de la extirpación. Conclusiones: Los tumores en Fosa Posterior originan diversas alteraciones neuropsicológicas similares a las observadas con lesiones en la corteza cerebral, dichas alteraciones se hacen más severas después de la extirpación del tumor; esta evolución puede presentar un dilema a la luz de la Bioética: ¿Se prolonga la vida a expensas de mayor deterioro neurocognitivo al quitar el tumor, o no se opera para evitar mayor deterioro en la calidad de vida y se reduce el tiempo de vida?.

Aim: Identify and describe the neuropsychological differences before and after surgery in 2 patients 8 years of age with a tumor in the posterior fossa. Methodology: Neuropsychological assessment was performed before and after surgery to 2 patients (8 years of age), one female with arachnoid cyst in paravermian cyst and another male with medulloblastoma in vermis and we compared the data obtained before removal of tumor and after. We use the following Neuropsychological Tests: WISC-IV was applied to assess IQ and Child Neuropsychological Assessment (ENI) was to evaluate cognitive functions. Results: The 2 patients had deficits in IQ, cognitive functions, the academic performance skills and his executive skills, even without chemotherapy or radiotherapy, both before surgery and after removal of the tumor. These functions worsened after surgery. Conclusions: Posterior fossa tumors originate many various neuropsychological similar to those observed in cerebral cortex, these changes are most evident after removal of the tumor, this evolution can present a dilemma in light of Bioethics: Is justified to prolong the life at expense of neurocognitive impairment, after removing a big tumor, or not to operate preventing further deterioration in the quality of life and reducing the lifetime?.

Management of obstructive hydrocephalus before posterior fossa tumor resection in children / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the management of obstructive hydrocephalus caused by posterior fossa tumors before tumor resection in children.</p><p><b>METHODS</b>The clinical data were reviewed of 162 pediatric patients of posterior fossa tumors with obstructive hydrocephalus undergoing surgical tumor removal between January 2008 and June 2012. Ninety children received preoperative Ommaya external drainage (group A) and 72 underwent preoperative ventriculo-peritoneal shunting (V-Ps) (group B). The therapeutic effects were evaluated and compared between the two groups.</p><p><b>RESULTS</b>Postoperative complications found in a total of 67 cases including infection (27), shunt blockage (19), subdural hematoma or effusion (16), ventricle fissure syndrome (5), and tumor hernia (4). Significant differences were found in the incidences of shunt blockage (P=0.047) and subdural hematoma or effusion (P=0.039) but not in the incidences of intracranial infection (P=0.478) or tumor hernia (P=0.462) between the two groups.</p><p><b>CONCLUSION</b>Ommaya reservoir can produce good results through simple surgical procedures for treatment of acute hydrocephalus in children with posterior fossa tumors and is associated less trauma and complications.</p>

Tortícolis recurrente como forma de presentación de un tumor de la fosa posterior del cerebro / Recurrent torticollis as a form of presenting a tumor in the posterior fossa brain

La tortícolis se presenta como una manifestación focal del sistema nervioso central, y es una afección poco frecuente, aunque puede ser el síntoma inicial en patologías de la fosa posterior del cerebro. Se presenta el caso de un paciente masculino de cuatro años de edad, con antecedentes de dolor, lateralización y torsión del cuello con nueve meses de evolución, cuyos síntomas se mantuvieron progresando. Gradualmente se asocian cefalea, náuseas e inestabilidad a la marcha. Al realizar el examen físico se encontraron elementos clínicos de una tortícolis y un síndrome cerebeloso de hemicuerpo derecho. Se realizó una resonancia magnética nuclear de cráneo, la cual evidenció una lesión sólida que ocupaba todo el piso del IV ventrículo, y se extendía hasta el segundo segmento medular cervical. Se efectuó abordaje quirúrgico de la fosa posterior del cerebro y exeresis de la lesión. El diagnóstico histológico fue el de un ependimoma. Aunque la tortícolis la mayoría de las ocasiones es una condición benigna, cuando se presenta secundariamente en los niños, uno de los diagnósticos diferenciales que deben tenerse en cuenta, son los tumores de la fosa posterior del cerebro, como ocurrió en este caso

Torticollis is presented as a focal demonstration of the central nervous system, and it is a rare condition, but it may be the initial symptom in diseases of the posterior fossa brain. We report the case of a male patient aged four, with a history of pain, lateralization and twisted neck with nine months of evolution, whose symptoms were progressing. Gradually, headache, nausea and gait instability are associated. When performing the physical examination, we found clinical elements of a stiff neck and a right hemisphere cerebellar syndrome. We performed a cranial MRI, which showed a solid lesion occupying the entire floor of the fourth ventricle, and it extended to the second cervical spinal segment. Surgical approach was performed in the posterior fossa and brain tumor excision. Ependymoma was the histological diagnosis. Though most occasions, torticollis is a benign condition, when it occurs secondarily in children, one of the differential diagnoses that should be considered is the posterior fossa tumors of the brain, as in this case

Astrocitoma pilomixoide de fossa posterior em criança: relato de caso / Pilomyxoid astrocytoma of the posterior fossa in children: case report

Descrever um caso de astrocitoma pilomixoide, um tumor do sistema nervoso central raro, descrito e classificado recentemente diante de sintomatologia e achados pouco específicos. Análise e descrição de um caso de astrocitoma pilomixoide submetido a tratamento cirúrgico no Instituto José Frota, Fortaleza, Ceará. Paciente evolui com regressão importante dos sintomas, sem indícios de recidiva tumoral. O diagnóstico e a classificação correta dos tumores cerebrais são de extrema importância clínica, pois modificam de forma impactante o prognóstico, assim como a abordagem terapêutica.

To describe a pilomyxoid astrocytoma case, a tumor of the central nervous system rare recently described and classified in the face of a specific symptomatology and little found. Analysis and description of a case of pilomyxoid astrocytoma underwent surgical treatment at the José Frota Institute in Fortaleza, Ceará. Patient developed a significant decrease of symptoms without evidence of tumor relapse. The diagnosis and the correct classification of cerebral tumors are of extreme clinical importance, because it changes so as impacting the prognosis as well as therapeutic approach.

Posterior fossa tumor in children

Primary brain tumors are the most common solid neoplasms of childhood, representing 20% of all pediatric tumors. The best current estimates place the incidence between 2.76 and 4.28/100,000 children per year. Compared with brain tumors in adults, a much higher percentage of pediatric brain tumors arise in the posterior fossa. Infratentorial tumors comprise as many as two thirds of all pediatric brain tumors in some large series. Tumor types that most often occur in the posterior fossa include medulloblastoma, ependymoma, cerebellar astrocytoma and brainstem glioma. All pediatric cases of posterior fossa tumor that were considered for surgery from 1981 to 2011 were selected and the demographic data including age, gender and tumor characteristics along with the location and pathological diagnosis were recorded. The surgical outcomes were assessed according to pathological diagnosis. Our series consisted of 84 patients [52 males, 32 females]. Cerebellar symptoms were the most common cause of presentation [80.9%] followed by headache [73.8%] and vomiting [38.1%]. The most common histology was medulloblastoma [42.8%] followed by cerebellar astrocytoma [28.6%], ependymoma [14.3%], brainstem glioma [7.2%] and miscellaneous pathologies [e.g., dermoid, and tuberculoma] [7.2%]. The diagnosis of brain tumors in the general pediatric population remains challenging. Most symptomatic children require several visits to a physician before the correct diagnosis is made. These patients are often misdiagnosed for gastrointestinal disorders. Greater understanding of the clinical presentation of these tumors and judicious use of modern neuroimaging techniques should lead to more efficacious therapies

Metástasis supratentorial de meduloblastoma de fosa posterior / Supratentorial metastasis of P-fosa medulloblastoma

Objective: our objective is to analyze the patients that presented supratentorial metastases. Material and methods: we studied 170 patients with medulloblastoma from the year 1991 to 2005. Twenty seven presentedsupratentorial metastases. We considered age at presentation, pathology, staging, dissemination to other places and outcome. Results: twenty seven patients (15,8%) with medulloblastoma presented supratentorial metastases, the average age was 5,87 years range from 3 to 11 years. 13/27 were staged high risk and 14/27 standard. The average time between surgery and presence of recurrence was 12,65 month. 12/27 presented desmoplasia. 25/27 patients died. Conclusion: 15,8% of patients with medulloblastoma presented supratentorial metastases before 16 months of the first surgery. Allthe patients were younger than 12 years. The appearance of supratentorial metastases is not related with the stage or the presence of desmoplasia. The outcome was unfavorable once the dissemination was diagnosed.

Cisto epidermoide da fossa posterior: relato de caso / Epidermoid cyst of the posterior fossa: a case report

Epidermoid cysts of the central nervous system are uncommon conditions, which are frequently located in the cerebellopontine angle and around the pons. They are covered with keratinized squamous epithelium and keratin lamella, which give its contents a soft, white-pearly appearance. Epidermoid cysts are mostly originated from malformations, presumably associated with surface elements of the nervous system ectoderm during the closure of the neural groove or formation of secondary cerebral vesicles. The authors describe a case of epidermoid cyst in the posterior fossa causing hydrocephalus and review morphologic and diagnostic criteria of this lesion.

Os cistos epidermoides do sistema nervoso central (SNC) são condições incomuns, estando localizados mais frequentemente no ângulo pontocerebelar e ao redor da ponte. Eles são revestidos por epitélio escamoso queratinizado e lamelas de queratina, tornando seu conteúdo branco-perolado e pastoso. Os cistos epidermoides são, na maioria das vezes, originados de malformações, possivelmente associados ao entremeio de elementos superficiais do ectoderma do SNC durante o fechamento da placa neural, ou formação das vesículas cerebrais secundárias. Os autores descrevem um caso de cisto epidermoide da fossa posterior determinando hidrocefalia e revisam critérios morfológicos e diagnósticos dessa lesão.

Monitoração neurofisiológica intraoperatória em tumores de ângulo pontocerebelar: papel de parâmetros distintos na predição do resultado funcional do nervo facial / Intraoperative neurophysiology monitoring for cerebellopontine angle tumors: role of distinctive parameters in predicting the facial nerve functional outcome

Nas cirurgias de ressecção de tumores do ângulo pontocerebelar, a preservação do nervo facial está entre os seus principais objetivos. Diversas técnicas neurofisiológicas vêm sendo empregadas com o objetivo de predizer déficit imediato do nervo facial no pós-operatório, como a eletromiografia contínua para registro de atividade neurotônica tipo A, a estimulação direta do nervo facial no sítio tumoral e a estimulação elétrica transcraniana com captação em músculos de face. Analisamos 23 pacientes de forma prospectiva, submetidos à cranectomia retrossigmoide para ressecção de tumores em fossa posterior no período de janeiro de 2008 a março de 2010. Os pacientes foram avaliados clinicamente de acordo com a gradação de House-Brackmann para a função do nervo facial. Foram observadas a ocorrência de atividade neurotônica do tipo A, também chamada de atividade irritativa, a queda da amplitude do potencial motor do nervo facial obtido com a estimulação elétrica transcraniana e o aumento na intensidade do estímulo elétrico da estimulação elétrica transcraniana para a obtenção desse potencial. Esses dados foram relacionados à condição clínica do nervo facial no pós-operatório imediato e na última data de acompanhamento. Observamos que a queda da amplitude do nervo facial acima de 60% do seu valor inicial basal foi a variável mais sensível (89%) e com maior valor preditivo positivo (92%) para a piora clínica do nervo facial. A ocorrência de atividade irritativa isolada foi a variável menos sensível (7%) e com valor preditivo positivo de apenas 25%. O aumento na intensidade da estimulação elétrica transcraniana não mostrou significância estatística (p = 0,287). Concluímos que das variáveis estudadas, a queda na amplitude do potencial evocado motor do 7º nervo craniano acima de 60% foi a melhor na predição de piora clínica imediata do nervo facial.

The preservation of facial nerve function is one of the most important goals of the cerebellopontine angle tumor resection surgeries. Valuable neurophysiologic techniques have been used to predict the facial nerve outcome, such as continuous electromyography to identify neurotonic activity type A, direct facial nerve stimulation in the vicinity of the tumor and transcranial motor evoked potential recording in face muscles. We analyzed 23 patients undergoing retrossigmoidectomy approaches for posterior fossa tumor resection between January 2008 and March 2010. Their facial nerve function was evaluated using the House-Brackmann score. We correlated the occurrence of type A neurotonic activity, facial nerve motor evoked potential amplitude obtained with transcranial electrical stimulation and increase in the electric stimulus threshold to the immediate and last follow-up facial nerve outcome. In this series, the increase in electric stimulus threshold showed no statistical significance (p = 0,287). The drop of the facial nerve motor evoked potential amplitude equal or above 60% was the most sensitive (89%) and with the highest positive predictive value (92%) in identifying poor facial nerve outcome. The occurrence of neurotonic activity type A showed to be the least sensitive (7%) and with the poorest positive predictive value (25%) of them. We conclude that among the used parameters, the drop of the final 7º nerve motor evoked potential amplitude equal or above 60% of basal recording was the best one in predicting poor facial nerve outcome.

Metastatic brain tumors: a retrospective review in east Azarbyjan [Tabriz]

A set of one hundred and twenty nine patients with known primary malignancy and suspected brain metastasis was reviewed in present study. The patients were selected among patients presented to the MRI section of Imam Khomeini Hospital or a private MRI center in Tabriz [Iran]. Primary tumor site, clinical manifestations, number and site of lesions were identified in this patient population. The primary tumor site was breast in 55 patients [42.6%], followed by lung [40.3%], kidney [7.7%], colorectal [4.6%], lymphoma [3.1%] and melanoma [1.5%]. Most patients were presented with features of increased intracranial pressure [headaches and vomiting], seizures and focal neurologic signs. Single brain metastasis occurred in 16.3% of patients, while multiple lesions accounted for 83.7% of patients. Ninety seven patients had supratentorial metastases [75.2%]. Twenty cases [15.5%] had metastases in both compartments. Infratentorial lesions were observed only in twelve patients [9.3%]

Multicentric astrocytoma presenting with supra- and infratentorial involvement: a case report

This report describes the case of a 56 year-old man with a history of diplopia. His brain imaging showed multiple lesions with a metastatic appearance, however all investigations to determine the primary source of malignancy were negative. The patient underwent a brain biopsy, which was positive for anaplastic astrocytoma, a rare tumor that should be considered in the differential diagnosis of secondary brain tumors