Ependimoma intracraneal: apuntes clínicos, moleculares y anatomopatológicos / Intracranial ependymoma: clinical, molecular and pathological notes

RESUMEN Los ependimomas surgen de las células ependimarias que revisten los ventrículos y los pasajes en el encéfalo y el centro de la médula espinal. Las células ependimarias producen líquido cefalorraquídeo. Se decidió la realización de una revisión acerca del ependimoma intracraneal teniendo en cuenta que no existe artículo nacional que trate este tema, siendo la mayoría de los trabajos consultados referentes a la misma variante histológica pero en localización espinal, cuyo objetivo es describir la características clínicas, moleculares y anatomopatológicas del ependimoma intracraneal. Se realizó la búsqueda de artículos en revistas de las bases de datos: PubMed, Scielo y EBSCO. La búsqueda se limitó a artículos con el texto completo, publicados fundamentalmente en los últimos cinco años. El ependimoma intracraneal es un tumor frecuente en la edad pediátrica, sus manifestaciones clínicas dependen de su localización, presenta una gran diversidad molecular y anatomoptológica (AU).

SUMMARY Ependymomas arise from ependymal cells that line the ventricles and passages in the brain and center of the spinal cord. Ependymal cells produce cerebrospinal fluid. It was decided to conduct a review about intracranial ependymoma taking into account that there is no national article dealing with this issue, with most of the works consulted referring to the same histological variant but in spinal location, whose objective is to describe the clinical characteristics, Molecular and pathological pathways of intracranial ependymoma. We searched articles in journals of the databases: PubMed, Scielo and EBSCO. The search was limited to articles with the full text, published mainly in the last five years. Intracranial ependymoma is a frequent tumor in the pediatric age, its clinical manifestations depend on its location, it has a great molecular and anatomoptological diversity (AU).

Ependymoma with Intraorbital Extracerebral Recurrence: Case Report

Ependymomas are rare neuroepithelial tumors that originate from a type of glial cell called ependymal cell. In general, they correspond to 1.2 to 7.8% of all intracranial neoplasms, and to2 to 6%of all gliomas. Although it corresponds only to2 to 3%of all primary brain tumors, ependymoma is the fourthmost common cerebral neoplasmin children, especially in children younger than 3 years of age.1,2 In patients younger than 20 years of age, the majority (90%) of ependymomas are infratentorial,more precisely from the IV ventricle. In spite of this, in adults, medullary ependymomas are more frequent (60%). In this context, supratentorial and extraventricular ependymomas, as in the case reported in the present article, are infrequent in both adults and children.1,2 Both sexes are equally affected.3 Recurrence of intracranial ependymomas occurs in almost 50% of the cases, and the followup outcome is not favorable.4 In another perspective, the recurrence of extracerebral ependymomas is extremely rare, and even more unusual in the intraorbital site, as it occurred in the case in question.

Hallazgo de quiste ependimario (ependimoma) intramedular en el estudio de la vía piramidal y síndrome siringomiélico / Finding of intramedullary ependymal cyst (Ependymoma) in the study of pyramidal tract and syringomyelic syndrome

Introducción: Una paresia tiene que ser objeto de un detallado análisis para conocer su correcta etiología. La exploración física debe incluir una minuciosa valoración neurológica que oriente la localización de la lesión. Caso Clínico: Paciente con paresia de extremidad inferior derecha, hiperreflexia, clonus y disminución de sensibilidad térmica y algésica por debajo de la apófisis xifoides. Estos hallazgos señalan a nivel vertebral dorsal, D8, posible localización de una lesión que afecta a la vía piramidal motora y la vía sensitiva. La sospecha clínica se confirma mediante RMN que mostró la presencia de masa intramedular, posible ependimoma. Conclusiones: El conocimiento de la anatomía de los haces nerviosos que discurren por la médula espinal y la información nerviosa que proporcionan, contienen signos clínicos motores y sensitivos que permiten discernir qué haces nerviosos están lesionados. Este juicio clínico puede dirigir, de manera mucho más concreta, hacia el tipo de exploraciones y pruebas complementarias que pueden ser necesarias para concretar un diagnóstico y reducir el gasto sanitario, así como el tiempo de espera para un posible tratamiento quirúrgico(AU)

Introduction: A paresis must be the object of a detailed analysis to know its correct etiology. Physical examination should include a thorough neurological assessment to guide the location of the lesion. Clinical case: Patient with paresis of the lower right extremity, hyperreflexia, clonus, and decreased thermal and algic sensitivity below the xiphoid process is preseneted. These findings point to the dorsal vertebral level, D8, possible location of a lesion that affects the pyramidal motor pathway and the sensory pathway. Clinical suspicion is confirmed by MRI that showed the presence of intramedullary mass, possible ependymoma. Conclusions: The knowledge of the anatomy of the nerve bundles that run through the spinal cord, and the nerve information they provide contain clinical and sensory clinical signs, allowing to discern which nerve bundles are injured. This clinical judgment can lead, in a much more concrete way, to the type of explorations and complementary tests that may be necessary to diagnose and reduce health costs, as well as the waiting time for a possible surgical treatment(AU)

Ependimoma anaplásico supratentorial cortical. Reporte de caso / Cortical supratentorial anaplastic ependymoma. Case report

Introducción: Los ependimomas son tumores neuroepiteliales que representan del 2 al 9% de todos los tumores del SNC. Existe una variante ectópica que se ubica alejada de las células ependimarias que darían su origen. Esta última variante se presenta más frecuentemente en el compartimiento supratentorial. Objetivo: Reporte de un caso de ependimoma anaplásico occipital cortical y revisión de la literatura de esta entidad con una baja casuística mundial.Reporte de caso: Masculino de 35 años, ex tabaquista, cefalea de 2 meses de evolución y disminución de la agudeza visual. Al examen se constató cefalea holocraneana, mareos y hemianopsia homónima derecha por confrontación. Fondo de ojo (FO): edema de papila bilateral, con hemorragias peripapilares en ojo izquierdo. Estudios neuroradiológicos: lesión cortical occipital izquierda con refuerzo homogéneo post contraste, limites netos y abundante edema perilesional. Screening oncológico negativo. Resección quirúrgica, la pieza quirúrgica presentaba buen plano de clivaje, coloración blanquecina y consistencia duroelástica. Hallazgos vinculables con Ependimoma Anaplásico. Se le realizó tratamiento adyuvante STUPP. Screening de siembra metastásica craneoespinal negativo. Al año post tratamiento no se evidenció recidiva de la lesión, con mejoría del CVC y sin edema de papila en el FO control. Conclusiones: Los ependimomas anaplásicos supratentoriales corticales son una entidad rara. En pacientes jóvenes con imágenes que evidencian lesión cortical única con realce homogéneo post contraste debe considerarse a esta entidad dentro de los diagnósticos diferenciales. La resección quirúrgica es el tratamiento de elección, seguido de RT, en variantes malignas o con resección incompleta.

Introduction: Ependymomas are neuroepithelial tumors, representing 2 to 9% of all CNS tumors. There is an ectopicvariant located away from the ependymal cells that wouldoriginate. This last variable occurs more frequently in thesupratentorial compartment.Objectives: Case report of an occipital cortical anaplasticependimoma. Literature review of this entity with a low globalcasuistry. Case report: Male 35 years, former smoker, headache 2 monthsof evolution and decreased visual acuity. Physical examination found holocraneal headache, dizziness and right homonymoushemianopia by confrontation. Ocular fundus (OF): bilateralpapilledema, peripapilar bleeding in left eye. Neuroradiological studies: left occipital cortical lesion with homogeneousreinforcement after contrast, net limits and abundant perilesionaledema. Negative oncological screening. Surgical resection, Thesurgical specimen showed good cleavage plane, whitish and firm,elastic consistency. Linkable findings with anaplasticependimoma. STUPP Adyuvant therapy was performed. Negativescreening of craniospinal metastatic seeding. During posttreatment year showed no recurrence of injury, with CVCimprovement, without papilledema in the ocular fundus control.Conclusions: Cortical supratentorial anaplastic ependimoma arerare. In young patients with images that show unique corticallesion with homogeneous reinforcement after contrast this entitymust be considered between differential diagnoses. Surgicalresection is the treatment of choice, followed by radiotherapy, inmalignant variants of incomplete resection.

Ependimoma mixopapilar dorsolumbar: reporte de un caso / Ependymoma myxopapillary dorsolumba: case report

Se presenta un caso con diagnóstico de Ependimoma mixopapilar de localización dorso lumbar con cuadro de presentación de paraparesia progresiva y que recibió tratamiento quirúrgico y oncológíco. La evolución no fue satisfactoria a pesar de mejorar el estado neurológico motor, por su grado de extensión y adherencia a estructuras nerviosas y óseas.

Intramedullary tumors in children: analysis of 24 operated cases / Tumores intramedulares em crianças: análise de 24 casos operados

Intramedullary tumors are rare. The authors reviewed 24 cases operated between 1996 and 2006. The study assessed the clinical characteristics and surgical results based upon the neurological function. METHOD: Medical records of patients with intramedullary astrocytoma and ependymoma were reviewed. The minimal follow up time was 6 months and, at the end of this period, a comparative analysis of the neurological function was performed based using the McCormick scale score. RESULTS: Most patients had astrocytoma (75 percent). Male gender was more prevalent (58.3 percent). The most common type of tumor was graded as I or II, and in three cases these were malignant. The total resection of the tumor was achieved in 20.8 percent of the cases. The statistical analysis did not show a statistically significant difference between preoperative and postoperative grades at McCormick scale. CONCLUSION: The authors concluded that microsurgery to intramedullary tumors did not significantly alter the neurological function after six months.

Os tumores intramedulares são doenças raras. Os autores analisaram 24 casos operados entre 1996 e 2006. O estudo analisou as características clínicas e o resultado da cirurgia quanto à função neurológica. MÉTODO: Foram analisados pacientes com astrocitomas e ependimomas intramedulares. O tempo mínimo de acompanhamento foi de 6 meses e ao final deste período foi realizada a avaliação comparativa da variação do estado neurológico baseado na escala de McCormick. RESULTADOS: A maioria dos pacientes era de astrocitoma (75 por cento). O gênero masculino foi mais prevalente (58,3 por cento). A maioria dos tumores era de grau I ou II, 3 casos eram malignos. A ressecção total do tumor ocorreu em 20,8 por cento dos casos. A avaliação estatística demonstrou que não houve diferença significativa entre o estado neurológico na escala de McCormick pré-operatória e pós-operatória. CONCLUSÕES: Os autores concluem que a microcirurgia para ressecção dos tumores intramedulares não ocasionou variação funcional significativa nos pacientes após seis meses da cirurgia.

Arachnoiditis mimicking recurrent spinal ependymoma

Spinal arachnoiditis is a cause of persistent symptoms or recurrence of symptoms in 6-16% of postoperative patient. Spinal arachnoiditis mimicking ependymoma tumour recurrence in a young child is reported here. A 9-year-old child was operated 3 years back for extensive lumbar and sacral ependymoma. He presented with short history of rapidly progressive paraparesis and radiology was stongly suggestive of recurrent tumour in lumbar spinal canal. However, surgery revealed only CSF loculation in the spinal canal. No tumour was seen. The patient improved after adhesiolysis. Postoperative spinal arachnoiditis can mimic tumour recurrence in ependymomas. This is an interesting case observed by us and we advise that the possibility of spinal arachnoiditis should be kept in mind in the differential diagnosis of causes of neurological deterioration in previously operated cases of ependymoma

Ependimoma supratentorial em criança: relato de caso / Supratentorial ependymoma in child: a case report

O ependimoma é um tumor glioneural do grupo neuroepitelial que se origina no epêndima, de crescimento lento e localização infratentorial em dois terços dos casos. Os infratentoriais são maiscomuns em crianças e os supratentoriais, nos adultos. O presente relato descreve um caso na infância,supratentorial, em íntimo contato com o ventrículo lateral, predominantemente cístico, com áreas sólidas, pequeno efeito expansivo regional, sendo evidenciado, pela anatomopatologia, tratar-se de um subtipo infrequente nesta faixa etária, o subependimoma.

Ependymoma is a neuroepithelial tumor of the glioneural group which originates in the ependima, with slow growth and infratentorial location in 2/3 of the cases. The infratentorials are morecommon in children and the supratentorials in adults. This reportdescribes a case in childhood, supratentorial, in close contact withthe lateral ventricle, predominantly cystic, with solid areas, little regional expansive effect and evidenced by the pathology as an infrequent subtype in this age group, the subependymoma.

Ependimoma intracraneano en la infancia / Intracranial ependymoma in infancy and childhood

El ependimoma es un tumor de lento crecimiento que se origina de células de la pared de los ventrículos cerebrales o del canal ependimario, que afecta preferentemente a los niños y adultos jóvenes. Corresponde histológicamente a grado II de la clasificación de la OMS (Organización Mundial de la Salud). La variante anaplásica corresponde al grado III. Representa el 6.12 % de los tumores intracraneanos en la infancia. La edad más frecuente es alrededor de los 6 años y no hay prevalencia de sexos. El ependimoma puede nacer en cualquier punto del sistema ventricular o del canal espinal o, alejados de ellos, de remanentes aislados en el parénquima cerebral. En los niños ocupa el tercer lugar de frecuencia en la fosa posterior, después del meduloblastoma y astrocitoma. La conducta biológica del ependimoma varía totalmente según esté localizado en el compartimiento supratentorial o en la fosa posterior: el ependimoma supratentorial no tiene un patrón radiológico característico y suele ser anaplásico; no obstante, como la resección es posible en la mayoría de los casos se puede hablar de curación. En cambio el ependimoma de fosa posterior que tiene un patrón radiológico característico, generalmente nace del piso del cuarto ventrículo lo que impide la resección total y por ende la curación, aunque sea de bajo grado. El tratamiento de elección del ependimoma es la resección total, y cuando ello no es posible se completa el tratamiento con radioterapia local conformada (acelerador lineal) sea un ependimoma de alto o bajo grado. La quimioterapia no es efectiva en el ependimoma.

Ependymoma is a slowly growing tumor, that takes origin from cells of the ventricular wall or the epndymal canal. It affects preferentially children and jung adults. Histologically it belongs to the OMS type II classification. The anaplastic variant belongs to the OMS grade III. It represents the 6.12% of the intracranial tumors in infancy andthe most frequent age of appearance is around 6 years without sex preference.In children is the third most frequent tumor of the posterior fossa, after medulloblastoma and astrocytoma.The biological behaviour of ependymoma varies after its locationin the posterior fossa or the supratentorial room. The supratentorialependymomoma has not a characteristic radiological pattern and is frequently anaplastic; however, because the totalresection is possible, it can be cured in most cases. On the other hand, the posterior fossa ependymoma having a typical radiologic pattern, grows habitually from the floor of the fourthventricle making impossible the total resection and therefore curation, even in low grade tumors. The elective treatment of ependymoma is total resection and, if not possible, it can be complemented with conformed localradiotherapy with linear acclerator, both for low or high grade tumors. Chemotherapy is ineffective in ependymomas.

Accuracy of cytologic diagnosis of central nervous system tumours in crush preparation.

The aim of this study was to assess the usefulness and accuracy of cytologic smears by making crush preparation as a diagnostic method, in central nervous system tumors. 278 patients with central nervous system tumors were investigated. In 98 cases, material was obtained intraoperatively during craniotomy and in 180 cases stereotactic biopsies were done. In all the cases crush preparations were made, and cytologic diagnosis was correlated with final histologic diagnosis. 244 out of 278 patients showed correlation with histopathological diagnosis. So, in present study diagnostic accuracy was 87.76%. In 18 cases no definite diagnosis was made due to inadequate material. Majority of the patients were in age group 31 to 40 years (72 cases). The youngest patient was three years old and the eldest was 87 years old. The most common tumor in intracranial cavity was astrocytoma (56.68%), followed by meningioma (6.88%), medulloblastoma (5.66%) and ependymoma (5.56%). The most common tumor in intraspinal cavity was ependymoma (38.46%), followed by meningioma (23.07%) and schwannoma (23.07%). In conclusion, crush preparation is an effective, simple, rapid, relatively safe and reliable technique for the diagnosis of central nervous system tumors. Diagnostic accuracy of cytology with final histopathological report is established with accuracy rate of 87.76%.

Is brain SPECT a suitable modality for evaluation of postradiotherapy posterior fossa brain tumours? A comparative evaluation with contrast enhanced computed tomography.

Single photon emission computed tomography (SPECT) of the brain is exquisitely sensitive in detecting viable tumour tissue in the supratentorial region, but its efficacy has not been properly evaluated till date in case of infratentorial posterior fossa tumours. Twenty-four patients with primary posterior fossa brain tumour were included in this study. In each case brain SPECT with 99mTc-glucoheptonate (GHA) was performed for the evaluation of disease status. Contrast enhanced computerised tomography of brain was also performed in all the patients. Brain SPECT was positive in four patients with recurrence of tumour as compared to fifteen cases with computed tomography with a mean GHA retention index 5.26 +/- 1.64. Patients with postradiation gliosis (n=9) showed lower GHA retention index of 1.24 +/- 0.27. This study demonstrates that brain SPECT is not sensitive in detecting recurrence of tumour tissue in infratentorial region, as it is in the supratentorial region, with a sensitivity of 20%, accuracy of 45.83% and negative predictive value of 40% and the chance of any single study coming as false negative is about 80%.

Supratentorial lobar anaplastic ependymoma resembling cerebral metastasis: a case report.

A 45-year-old man presented with progressive deterioration of vision. Visual acuity test revealed no light perception in both eyes. The fundoscopic examination demonstrated pale optic discs, consistent with secondary optic atrophy. Preoperative neuroimaging studies revealed a well-defined contrast-enhancing mass, 3 cm in diameter, at the left parietal region. Its radiologic appearances simulated those of cerebral metastases. A totally removed lesion was verified pathologically as an anaplastic clear cell ependymoma, which is rare in this location. A brief review of clinical features and neuroimaging of supratentorial lobar ependymoma is also included.

Estudo por imagens convencionais e espectroscopia de prótons por ressonância magnética dos tumores da fossa posterior na faixa etária pediátrica / Magnetic resonance imaging and proton magnetic resonance spectroscopy of pediatric posterior fossa tumors

Objetivou-se descrever e comparar os tumores da fossa posterior na faixa etária pediátrica através dos achados das IRM e 1H ERM. Realizou-se seqüências pesadas em T1, T2FLAIR, T1 pós-Gd e PRESS com voxel único no tumor. Encontrou-se 14 casos de meduloblastoma, 8 de astrocitoma pilocítico e 5 de ependimoma. O meduloblastoma diferenciou-se dodemais pela sua localização, isossinal em T2, cistos de pequenas dimensões, maioresrelaçõesCo/Ce Co/NAA. Os ependimomas diferenciaram-se pela extensão pelos forames de Luschka e Magendie e cistos de médias dimensões. Os astrocitoma pilocíticos diferenciaram-se pelo realce anelar, edema perilesional, cistos grandes e maior relação NAA/Cr / This study objetives to describe and compare the pediatric posterior fossa tumors by MRI and 1H MRS. We performed sequences weighted on T1, T2, FLAIR, Gd-T1, and single voxel PRESS technique in the tumor. We found 14 cases of medulloblastoma, 8 of pilocytic astrocytoma and 5 of ependymoma. The medulloblastomas were different due to their localization, their isosignal on T2 sequence, the smallest cysts, higher Cho/Cr and Cho/NAA ratios. The ependymomas were different because their extension to the foramen Luschka and Magendie and medium size cysts. The pilocytic astrocytomas were different due to the anelar gadolinium-enhancement, perilesional edema, the largest cysts and higher NAA/Cr ratio...

Intracranial and Spinal Ependymomas: Review of MR Images in 61 Patients

OBJECTIVE: To compare the age distribution and characteristic MR imaging findings of ependymoma for each typical location within the neuraxis. MATERIALS AND METHODS: During a recent eleven-year period, MR images of 61 patients with histologically proven ependymomas were obtained and retrospectively reviewed in terms of incidence, peak age, location, size, signal intensity, the presence or absence of cyst and hemorrhage, enhancement pattern, and other associated findings. RESULTS: Among the 61 patients, tumor location was spinal in 35 (57%), infrartentorial in 19 (31%), and supratentorial in seven (12%). In four of these seven, the tumor was located in brain parenchyma, and in most cases developed between the third and fifth decade. Approximately half of the infratentorial tumors occurred during the first decade. The signal intensity of ependymomas was nonspecific, regardless of their location. A cystic component was seen in 71% (5/7) of supratentorial, 74% (14/19) of infratentorial, and 14% (5/35) of spinal cord tumors. Forty- nine percent (17/35) of those in the spinal cord were associated with rostral and/or caudal reactive cysts. Intratumoral hemorrhage occurred in 57% (4/7) of supratentorial, 32% (6/19) of infratentorial, and 9% (3/35) of spinal cord tumors. In 17% (6/35) of spinal ependymomas, a curvilinear low T2 signal, suggesting marginal hemorrhage, was seen at the upper and/or lower margins of the tumors. Peritumoral edema occurred in 57% (4/7) of supratentorial, 16% (3/19) of infratentorial and 23% (8/35) of spinal cord tumors. Seventy-two percent (5/7) of supratentorial and 95% (18/19) of infratentorial tumors showed heterogeneous enhancement, while in 50% (17/34) of spinal cord tumors, enhancement was homogeneous. CONCLUSION: Even though the MR imaging findings of ependymomas vary and are nonspecific, awareness of these findings, and of tumor distribution according to age, is helpful and increases the likelihood of correct preoperative clinical diagnosis.

Esclerose múltipla, ependimoma medular e meningioma intracraniano: relato de caso / Multiple sclerosis, spinal cord ependymoma and intracranial meningioma: case report

Relatamos a associaçäo impar entre esclerose múltipla (EM), tumor medular e tumor intracraniano em uma paciente de 63 anos de idade e com EM há dez anos com evoluçäo em surtos de remissäo e exacerbaçäo. Havia melhora dos sintomas com o uso de corticosteráides. Em 1997 apresentou paraparesia crural e do membro superior direito, de instalaçäo progressiva e que näo respondeu à corticoterapia. A ressonância magnética da coluna cervical evidenciou tumor intramedular, que se revelou um ependimoma, e a do crânio, a presença de meningioma parietal à esquerda. Ressaltamos a associaçäo incomum entre tumores do sistema nervoso central e EM e enfatizamos a necessidade de investigaçäo clínica e por imagem diante de uma manifestaçäo ou evoluçäo clínica incomum no curso da doença

Clínica, diagnóstico y tratamiento de los ependimomas mixopapilares de la región sacra / Myxopapillary ependymomes of the sacral region: clinical manifestations, diagnosis and treatment

Se presentan dos pacientes portadores de tumores sacros con extensión pelviana que presentaban dolor y síntomas neurológicos de largo tiempo de evolución, y en los cuales la biopsia preoperatoria confirmó que se trataba de ependimomas mixopapilares. Los tumores eran de localización extradural, y se resecaron completamente por un abordaje posterior, logrando mejorar el estado neurológico preoperatorio y manteniendo la estabilidad sacroilíaca y lumbosacra. En el período de follow-up de casi 2 años, no hubo recurrencias tumorales. Conclusiones: a) las lesiones osteolíticas extensas del sacro son muy infrecuentes; b) la gran destrucción ósea no siempre está relacionada con metástasis sistémicas o mal pronóstico, pudiendo ser solamente un indicador de una compresión de larga data; c) la primera manifestación clínica, casi constante es el dolor local, aún en ausencia de signos neurológicos, de muy largo tiempo de evolución (meses o años), pudiendo aparecer en el curso evolutivo trastornos esfinterianos (20 por ciento de los casos) o fracturas patológicas con agravamiento neurológico agudo; d) la biopsia preoperatoria de los tumores de la región sacra es un procedimiento de gran valor para la elección de la modalidad de tratamiento y/o vía operatoria; e) las ventajas de la vía posterior para los ependimomas mixopapilares reside en que es el mejor abordaje para reconocer las estructuras neurales, permitiendo la inspección intradural si fuese necesario, al igual que procedimientos de estabilización; f) la radioterapia postoperatoria tiene su indicación en los pacientes con exéresis incompletas o luego del tratamiento del tumor recurrente

Audiometria de tronco cerebral (BERA) e eletrococleografia (ECoG) em uma criança operada de ependimoma intracraniano / Brain stem audiometry (BERA) and electrocochleography (ECoG) in a operated child of intracranial ependynoma

Os autores apresentam um caso de ependinoma intracraniano, localizado na regiäo do IV ventrículo, em criança de 3 anos. Após a remoçäo cirúrgica do tumor, houve perda auditiva unilateral, comprovada pela audiometria tonal limiar. A pesquisa da possível localizaçäo da lesäo do sistema auditivo através da eletrococleografia e audiometria do tronco cerebral mostrou que a lesäo se localizava no tronco cerebral. Este caso ilustra bem a importância da ECoG e do BERA no topo diagnóstico de lesöes de aparelho auditivo.