Pediatric pineal region tumors: institutional experience of surgical managements with posterior interhemispheric transtentorial approach.

PURPOSE: Resecting pineal region tumors in children is often challenging. Several approaches have been proposed and practiced. A personal series of pediatric pineal region tumors resected through craniotomy with posterior interhemispheric occipital transtentorial (OT) approach are reviewed. We present the surgical techniques, pitfalls, and their results. MATERIAL AND METHODS: Eighty patients ranging in age from 3 months to 21 years old, and treated over 3 decades were reviewed. Hydrocephalus caused the main presenting symptoms and was noted in 74 patients. It was treated prior to the craniotomy for tumor resection with endoscopic third ventriculostomy (ETV) in 33, external ventricular drainage in 26, and precraniotomy shunt in 15. Nine patients had ETV together with endoscopic biopsy. All patients had a parieto-occipital craniotomy in a prone position. Through a tentorial section, a gross total resection of the tumor was attempted except for germinomas. RESULTS: The tumor pathology showed 32 germ cell tumors (GCT), 22 benign astrocytomas, 13 pineal parenchymal tumors, 5 ATRTs, 3 papillary tumors, and 5 others. Of GCTs, 18 were teratomas. The extent of resection consisted of 55 gross total resections, 13 subtotal resections, 10 partial, and 2 biopsies with one postoperative death. Hemiparesis in 2, cerebellar ataxia in another 2, and hemiballismus in 1 were transient and improved over time. One had permanent hemisensory loss and another patient had bilateral oculomotor palsy. Postoperative homonymous hemianopia occurred in 2 patients but subsided over a short period of time. Parinaud's sign was noted in 24 patients, of which 16 were transient. CONCLUSION: The posterior interhemispheric OT approach provides a safe route and comfortable access to the pineal region in children. A great majority of postoperative neurological complications are the results of direct manipulations of the midbrain at tumor resection. Identification and preservation of the tumor-brain interface are of paramount importance. GCTs other than teratomas are treated with neoadjuvant chemotherapy and may eliminate the need for craniotomy. Exophytic midbrain JPAs are amenable to resection.

Temporal sylvian fissure arachnoid cyst in children: treatment outcome following microsurgical cyst fenestration with special emphasis on cyst reduction and subdural collection.

OBJECTIVES: Controversy remains regarding surgical managements of sylvian fissure arachnoid cyst (SFAC). This review presents our experience in the microsurgical fenestration of pediatric patients with SFAC to define surgical indication, and risks and benefits with special emphasis on postoperative subdural fluid collection (SDFC) and cyst size reduction. METHODS: Thirty-four children with SFAC who underwent microsurgical cyst fenestration at a single institution over a 10-year period were retrospectively reviewed for their clinical presentation, neuroimaging findings, and postsurgical course. The SFACs were classified by a novel grading system based on the degree of arachnoid cyst extension from the sylvian fissure to the insular cistern shown on MR images: grade 0 - little or no prominence of sylvian fissure, grade I - SFAC confined to the sylvian fissure, grade II - SFAC partially extending to the insular cistern, grade III - SFAC extending to the entire insular cistern. RESULTS: There were 26 males and 8 females. SFAC was present in the left side in 24. Twelve patients presented with cyst rupturing to the subdural space. Cyst grading did not show significant difference compared with rupture status (p > 0.9). All patients underwent microsurgical cyst fenestration. Postoperative SDFC is common but often resolved overtime in two-thirds of the cases with the mean average of 6 months. However, 3 patients had symptomatic postoperative SDFC and needed reoperation shortly after the first operation. Microsurgical cyst fenestrations for SFAC effectively resolved the presenting symptoms and often showed restorations of intracranial structures on follow-up imaging. Cyst resolution or reduction greater than 75% was noted in 61.8% of the patients postoperatively which was noted in a half of the SFAC of children even with age of 11 years or older. During the follow-up, no cyst recurrence or SDFC was noted. Patients with greater surgical reduction of cyst size tended to occur in younger children, and those with lower MR grade. CONCLUSION: Our results showed a high reduction rate of SFAC and brain re-expansion after microsurgical fenestration together with symptomatic improvements regardless the patient's age. Considering the developing CNS during childhood, reductions of a large space-occupying lesion followed by restorations of the structural integrity of the developing brain are very desirable. However, a multi-center cooperative prospective longitudinal study on long-term comparative data of those treated and untreated of neuro-psychological outcome and cyst rupture incidence is needed.

Benign skull and subdural lesions in patients with prior medulloblastoma therapy.

PURPOSE: To report on our institutional cohort of patients and review the literature of medulloblastoma patients who developed skull/subdural-based lesions following treatment. METHODS: Following institutional review board (IRB) approval, we retrospectively reviewed the medical records of four children with a history of treated medulloblastoma who developed non-specific skull-based/subdural lesions incidentally found on surveillance imaging. RESULTS: Biopsies of the lesions proved the pathology to be low grade and included inflammatory myofibroblastic tumor, cortical fibrous defect consistent with fibroma, fibrous tissue, and fibrous dysplasia. The finding of calvarial or subdural fibrous lesions in children following therapy for medulloblastoma was noted in four out of 201 (136 with available follow-up data) medulloblastoma patients seen or discussed in our institution over the past 10 years. CONCLUSIONS: These lesions can grow over time and pose a differential diagnostic challenge with metastatic disease when identified. The skull and subdural space should be scrutinized for secondary lesions on surveillance imaging of patients with medulloblastoma who have received craniospinal irradiation as knowledge of this benign occurrence will assist with management.

Infratentorial choroid plexus tumors in children.

OBJECTIVE: Choroid plexus tumors (CPTs) are rare pediatric intracranial neoplasms, and mostly occur in the lateral ventricle. CPTs located in the infratentorial location are considered to be rare in the pediatric population. We present a series of eight patients treated in the last decade at our institution focusing on clinical presentations and their outcome after excision. METHODS: We performed an institutional retrospective review of patients who underwent surgical resection of infratentorial CPTs during the period from 2008 to 2017. Patients' charts were reviewed for demographic data, clinical presentation, surgical treatment, and follow-up. RESULTS: There were eight patients (6 females and 2 males), with mean age for the cohort at presentation was 9.0 years. They represent 75% of 12 CPTs of all locations treated at the same period in our institution. These 8 infratentorial CPTs were in the fourth ventricle in seven, and in the cerebellopontine angle (CPA) in one. Seven patients had choroid plexus papillomas (WHO grade I) and 1 had an atypical choroid plexus papilloma (WHO grade II). Gross total resection was attempted in all patients. However, two of 3 patients with fourth ventricle floor invasion had subtotal resection with a thin layer of tumor left on the floor. The remaining 6 had a gross total resection. Six patients with preoperative hydrocephalus had a perioperative external ventricular drainage but none required permanent shunting after tumor resection. None showed recurrence/tumor progression without adjuvant therapy during the follow-up period of 20 months to 11 years. CONCLUSION: Infratentorial dominance among pediatric CPTs in this series contradicts previous reports. Infratentorial CPTs are amenable to surgical resection. Unresected small residuals due to invasion to the fourth ventricle floor showed no regrowth during 2 to 3 years follow-up without adjuvant therapy. However, these patients with incomplete resection need watchful observations.

Spring-Assisted Distraction Osteogenesis for the Treatment of Shunt-Induced Craniosynostosis.

Shunt-induced craniosynostosis is a rare complication of ventricular shunting for hydrocephalus in pediatric patients. Although the exact pathophysiology of this form of secondary craniosynostosis is not well understood, the current understanding is that persistent drainage of the ventricular shunt causes decreased dural tension, resulting in decreased expansile force on the cranium and premature sutural fusion. Due to the low incidence of this complication, there is no consensus on the ideal treatment for shunt-induced craniosynostosis. In recent years, distraction osteogenesis has been employed with greater frequency, as it is felt to counter the fundamental problem of decreased expansile force on the cranium. However, in a patient with a ventricular shunt, placement of external hardware in close proximity to the shunt could cause significant morbidity due to the increased risk of shunt infection. We present the management of a patient with shunt-induced craniosynostosis who continued to be shunt-dependent. We chose to use fully buried springs to create an expansile force on the cranium as an alternative to external distractors so as to mitigate the risk of infection. We demonstrate that spring-assisted distraction osteogenesis can be an effective treatment modality for patients with shunt-induced craniosynostosis. This method should be considered in patients with contraindications to external distraction devices, such as ongoing shunt dependency.

Primary Central Nervous System Malignant Melanoma in Children: A Case Series and Review of the Literature.

We describe 2 cases of rapidly progressive primary central nervous system malignant melanoma, and summarize 18 previously reported cases of this extremely rare tumor in children. Both patients presented with focal neurologic symptoms, with no evidence of skin or other organ system involvement. One patient was treated with temozolomide and etoposide, whereas the other was treated with multiple surgical resections, radiation therapy, and a trial of ipilimumab. New molecularly targeted and immune-based therapies used in metastatic melanoma in adults are potential new treatment options, but their efficacy and safety in pediatric patients needs to be established.

Atypical teratoid rhabdoid tumors of the posterior fossa in children.

PURPOSE: Atypical teratoid rhabdoid tumors (AT/RT) are rare, aggressive, central nervous system neoplasms that typically affect children under 3 years of age and have a very poor prognosis. Early case series consistently demonstrated rapid recurrence with progression to death, but more recent experience has shown significant improvements in progression free and overall survival. METHODS: A retrospective analysis of the clinical data of children diagnosed with AT/RT at the Ann & Robert H. Lurie Children's Hospital of Chicago (formerly Children's Memorial Hospital) between 2000 and 2014 was performed. Overall survival (OS) was used to describe outcome. Our small sample size and the utilization of different adjuvant regimens over the study period precluded a detailed statistical analysis. RESULTS: Eight children with AT/RT of the posterior fossa were included in our report. Gross total resection (GTR) was achieved in five children (63 %), two children underwent subtotal resection (25 %), and there was one who underwent biopsy. Patients were treated with various combinations of chemotherapy with or without conformal radiation therapy (RT). Median overall survival was 5 months (range 1 to 107 months) with two patients achieving sustained responses to 45 and 107 months. CONCLUSIONS: Our experience is in line with prior reports that show that children diagnosed with AT/RT of the posterior fossa have a poor prognosis, but that long-term survival is possible. These tumors provide many challenges, but contemporary series are beginning to show improvements in survival.

Choroid plexus tumors in pediatric patients.

OBJECTIVE: Choroid plexus tumors are rare intraventricular tumors, accounting for less than 1% of all intracranial tumors and 2-4% of brain tumors in children. The authors present their experience in the management of these lesions, and a review of the literature is performed. METHODS: We retrospectively analyzed the outcome of pediatric patients with choroid plexus tumors treated with surgical resection. The patients' charts were reviewed for demographic data, clinical presentation, surgical therapy and follow-up. RESULTS: This study involves 18 consecutive choroid plexus tumors: 14 papillomas, 2 atypical papillomas and 2 carcinomas. The tumor was located in the lateral ventricles (12), the fourth ventricle (4) and the third ventricle (2). The mean age at presentation was 4.6 years. Surgical resection was performed in all cases and no patients died perioperatively. Survival rate of papilloma patients was 100% without evidence of recurrent disease (mean follow-up for 73 months). Survival rate of carcinoma patients was 50% (mean follow-up for 23.5 months). One carcinoma patient died of disseminated disease 13 months after surgery. The functional outcome in long-term survivors after papilloma surgery was excellent. Postoperative extraventricular drainage (EVD) was performed in 12 patients. Five patients (27.8%) had persistent hydrocephalus after tumor resection and required a ventriculoperitoneal shunt. CONCLUSION: Choroid plexus papilloma is a surgically curable disease. Postoperative EVD was considered effective in lowering the rate of shunt requirement through releasing the blood-tinged CSF and small particles of tumor residue.

Diffuse postoperative cerebellar swelling in medulloblastoma: report of two cases.

BACKGROUND: We report two cases of diffuse cerebellar swelling with upward transtentorial herniation following medulloblastoma resection. We present our insight for managing medulloblastoma with aggressive clinical behavior. Case 1 is a 32-month-old boy. Magnetic resonance imaging (MRI) revealed fourth ventricular mass with diffuse leptomeningeal metastasis. He underwent gross total resectioning of the tumor and histopathology revealed a large cell medulloblastoma. A ventriculoperitoneal shunt was placed on the 25th postoperative day. Ten days after he developed lethargy, and MRI showed diffuse cerebellar swelling with upward herniation. He underwent emergent posterior fossa decompression; however, he remained unresponsive since then. Case 2 is a 31-month-old boy. MRI revealed a fourth ventricular mass with diffuse leptomeningeal metastasis. He underwent gross total resection and histopathology was a large cell medulloblastoma. Due to developing ventriculomegaly, extraventricular drainage was reinserted on the 11th postoperative day. Four days after, he developed lethargy and decerebrate posturing. MRI showed diffuse cerebellar swelling with upward herniation. He underwent aggressive posterior fossa decompression. Chemotherapy was started postoperatively. Gradually, his movement of extremities improved. On the 79th postoperative day, he started to follow commands and talk some words. He was discharged to a rehabilitation institute and has continued to improve since then. CONCLUSION: Diffuse cerebellar swelling with upward herniation could occur in patients with aggressive medulloblastoma postoperatively. Our patients had diffuse leptomeningeal dissemination of the tumor at the initial presentation. Close monitoring and prompt diagnosis with earlier surgical posterior fossa decompression and administration of chemotherapy may prevent irreversible neurologic deterioration.

Direct percutaneous transcarotid approach for embolization of dural sinus malformation in a premature neonate: A case report.

CONCLUSIONS: Direct percutaneous TCAA can be a feasible access for intracranial interventions in neonates with LBW and unavailable UA access.

Endoscopic third ventriculostomy for obstructive hydrocephalus in children younger than 6 months of age.

PURPOSE: The outcome of endoscopic third ventriculostomy (ETV) is worse in children younger than 2 years old and especially in infants, and controversies still exist whether ETV might be superior to shunt placement in this age group. We retrospectively analyzed the data of 23 patients younger than 6 months of age treated with ETV and assessed its feasibility as a first choice of treatment for hydrocephalus. METHODS: Between 1994 and 2008 in our clinic, 23 patients younger than 6 months having presented with obstructive hydrocephalus were treated endoscopically. The etiology of hydrocephalus was congenital aqueduct stenosis in 11 patients, posthemorrhagic obstruction in six patients, myelomeningocele in two patients, postmeningitis in two patients, Chiari I malformation in one patients, and Dandy walker variant in one patient. ETV was considered successful when no shunt operation was needed in the patient. RESULTS: ETV was successful in eight patients with regression of intracranial hypertension. In the remaining 15 patients, ventriculoperitoneal shunt implantation was necessary. Total success rate in our group of patients was 34.8%. In patients younger than 3 months of age (n=12), success rate was 25.0%. In patients from 3 to 6 months of age (n=11), success rate was 45.5%. Complication included intraventricular hemorrhage in one patient, meningitis and cerebrospinal fluid leak in one patient, and meningitis in one patient. CONCLUSIONS: Based on our experience, ETV could be the first method of choice for hydrocephalus in children younger than 6 months of age, especially in patients older than 3 months of age.

Safety and outcome of combined endovascular and surgical management of low grade cerebral arteriovenous malformations in children compared to surgery alone.

PURPOSE: To evaluate the outcomes of combined preoperative embolization and microsurgical resection in comparison with microsurgical resection alone as the current standard of care for low-grade cerebral arteriovenous malformations (AVM) in the pediatric population. MATERIALS & METHODS: We performed a single-center retrospective study of pediatric patients presenting with Spetzler-Martin (SM) grade I and II cerebral AVMs at a high-volume tertiary pediatric hospital between January 2005 and September 2016. Low grade AVM patients were divided into two groups: pre-operative embolization with subsequent microsurgical resection or microsurgical resection alone. Patient demographics, clinical and imaging presentations, AVM morphological characteristics, post-operative complications, and mid to long-term clinical outcomes were studied. Post-embolization and post-surgical outcomes were assessed prior to and after treatment, at 3 months and at final follow-up using the modified Rankin Scale (mRS) to compare both final independent (mRS 0-2) and favorable (no change or improved mRS) clinical outcomes for comparison between study groups. Statistical associations of patient demographics, AVM characteristics/SM grading, and treatment modality group with post-operative complications were performed using univariate logistic regression analysis. RESULTS: Thirty-four patients with low grade cerebral AVMs met the study inclusion criteria (mean age 10.6 ± 3.4 years; range 3-16 years, 22M:12 F). Twenty patients (59%) presented with ruptured AVMs. Twenty-five patients (73.5%) underwent combined treatment with embolization and microsurgical resection, while 9/34 (26.5%) underwent microsurgical resection alone. A total of 35 embolization procedures performed in 25 patients (Mode, 1; Range, 1-7) were associated with two minor post-embolization and 7 subsequent post-surgical (28%) complications, resulting in clinical deterioration in a single patient. Microsurgical resection alone was associated with 3 post-surgical complications (33%), resulting in permanent neurological disability in a single patient. There was no significance association of post-operative complications with either treatment modality group, combined treatment versus surgical resection alone [OR:1.13; 95% CI:0.23-5.62; p-value 0.88]. SM Grade II and eloquent locations were found to be significantly associated with post-surgical complications of low grade pediatric cerebral AVMs [OR 13.2 and OR 8 respectively, p-value 0.004 and 0.005). On mean follow-up time of 35.7 months, final clinical outcome was favorable in the majority of both treatment arms with no dependent (mRS>2) patients in the combined endovascular and surgical cohort. Two patients in the surgical cohort failed to achieve independent functional status, primarily due to a pre-operative morbid status (p-value 0.015). However, there was no significant difference in favorable outcomes between the treatment groups [p-value 0.14]. CONCLUSION: Our study suggests equivalent safety and favorable clinical outcomes related to combined endovascular embolization and microsurgical resection of low grade pediatric cerebral AVMs in comparison to microsurgical resection alone. On long term clinical follow-up, the vast majority of patients achieved an independent and favorable functional status irrespective of pre-operative embolization.

Pediatric primary spinal atypical teratoid rhabdoid tumor: a case series and review of the literature.

Atypical teratoid rhabdoid tumors (ATRTs) are rare malignant central nervous system tumors, commonly occurring before 3 years of age. Median overall survival (OS) of patients with these tumors is about 1 year, despite aggressive multimodal therapy. Pediatric primary spinal ATRTs are even more rare, with fewer than 50 cases reported. The authors present a series of four patients who were treated at Ann and Robert H. Lurie Children's Hospital of Chicago in the period from 1996 to 2017.These patients, with ages 2-11 years, presented with pain and a decline in motor functions. They were found to have lesions in the lumbar, thoracic, and/or cervical spine. One patient's tumor was intramedullary with exophytic components, while another patient's tumor had both intra- and extradural components. All patients underwent resection followed by chemotherapy (systemic and intrathecal). Two patients had fractionated radiation therapy and one had an autologous stem cell transplant. Three patients are known to be deceased (OS 8.5-45 months). The fourth patient was in remission 19 years after her initial diagnosis. To the authors' knowledge, this is the largest series of pediatric primary spinal ATRTs documented at a single institution. These cases illustrate a variety of presentations of spinal ATRT and add to the body of literature on this aggressive pathology.A systematic MEDLINE search was also conducted using the keywords "atypical teratoid rhabdoid tumor," "pediatric spinal rhabdoid tumor," and "malignant rhabdoid tumor spine." Reports were included for patients younger than 21 years, without evidence of intracranial or systemic disease at the time of diagnosis. Clinical characteristics and outcomes of the four institutional cases were compared to those in the literature. This review yielded an additional 48 cases of primary pediatric spinal ATRTs reported in the English-language literature. Patients (ages 2 months to 19 years) presented with symptoms of pain, regression of motor function, and spinal cord compression. The majority of tumors were intradural (14 extramedullary, 8 intramedullary, 1 both). Eleven cases in the literature described tumors limited to extradural structures, while 10 tumors involved the intra- and extradural spine. Four reports did not specify tumor location. Although rare, spinal ATRT should be considered in the differential diagnosis of pediatric patients presenting with a new spinal mass.

Phase I study of gene-mediated cytotoxic immunotherapy with AdV-tk as adjuvant to surgery and radiation for pediatric malignant glioma and recurrent ependymoma.

BACKGROUND: Gene-mediated cytotoxic immunotherapy (GMCI) is a tumor-specific immune stimulatory strategy implemented through local delivery of aglatimagene besadenovec (AdV-tk) followed by anti-herpetic prodrug. GMCI induces T-cell dependent tumor immunity and synergizes with radiotherapy. Clinical trials in adult malignant gliomas demonstrated safety and potential efficacy. This is the first trial of GMCI in pediatric brain tumors. METHODS: This phase I dose escalation study was conducted to evaluate GMCI in patients 3 years of age or older with malignant glioma or recurrent ependymoma. AdV-tk at doses of 1 × 1011 and 3 × 1011 vector particles (vp) was injected into the tumor bed at the time of surgery followed by 14 days of valacyclovir. Radiation started within 8 days of surgery, and if indicated, chemotherapy began after completion of valacyclovir. RESULTS: Eight patients (6 glioblastoma, 1 anaplastic astrocytoma, 1 recurrent ependymoma) were enrolled and completed therapy: 3 on dose level 1 and 5 on dose level 2. Median age was 12.5 years (range 7-17) and Lansky/Karnofsky performance scores were 60-100. Five patients had multifocal/extensive tumors that could not be resected completely and 3 had gross total resection. There were no dose-limiting toxicities. The most common possibly GMCI-related adverse events included Common Terminology Criteria for Adverse Events grade 1-2 fever, fatigue, and nausea/vomiting. Three patients, in dose level 2, lived more than 24 months, with 2 alive without progression 37.3 and 47.7 months after AdV-tk injection. CONCLUSIONS: GMCI can be safely combined with radiation therapy with or without temozolomide in pediatric patients with brain tumors and the present results strongly support further investigation. CLINICAL TRIAL REGISTRY: ClinicalTrials.gov NCT00634231.

Medulloblastoma arising from an immature teratoma of the posterior fossa. Case report.

Teratomas, a group of nongerminomatous germ cell tumors, account for 3% of all childhood tumors. These unusual lesions reproduce the cellular and structural phenotypic traits associated with the three classic germ layers in inappropriate places in the body and often retain an embryonal character. These immature cells can differentiate into more malignant neoplasms. An intracranial location for this lesion type is rare. The authors describe the case of a 2-year-old boy with a teratoma of the posterior fossa that had partially differentiated into a medulloblastoma.

Planning and Executing the Neurosurgery Boot Camp: The Bolivia Experience.

BACKGROUND: The neurosurgical boot camp has been fully incorporated into U.S. postgraduate education. This is the first implementation of the neurosurgical boot in a developing country. To advance neurosurgical education, we developed a similar boot camp program, in collaboration with Bolivian neurosurgeons, to determine its feasibility and effectiveness in an international setting. METHODS: In a collective effort, the Bolivian Society for Neurosurgery, Foundation for International Education in Neurological Surgery, Solidarity Bridge, and University of Massachusetts organized and executed the first South American neurosurgical boot camp in Bolivia in 2015. Both U.S. and Bolivian faculty led didactic lectures followed by a practicum day using mannequins and simulators. South American residents and faculty were surveyed after the course to determine levels of enthusiasm and their perceived improvement in fund of knowledge and course effectiveness. RESULTS: Twenty-four neurosurgery residents from 5 South American countries participated. Average survey scores ranged between 4.2 and 4.9 out of 5. Five Bolivian neurosurgeons completed the survey with average scores of 4.5-5. This event allowed for Bolivian leaders in the field to unify around education, resulting in the formation of an institute to continue similar initiatives. Total cost was estimated at $40 000 USD; however, significant faculty, industry, and donor support helped offset this amount. CONCLUSION: The first South American neurosurgical boot camp had significant value and was well received in Bolivia. This humanitarian model provides a sustainable solution to education needs and should be expanded to other regions as a means for standardizing the core competencies in neurosurgery.

Seizure Outcomes in Children Following Electrocorticography-Guided Single-Stage Surgical Resection.

BACKGROUND: In children with abnormal imaging, single-stage epilepsy surgery is an attractive alternative to the two-stage approach that relies on invasive recording of seizures. Implanted electrodes carry risks of their own and extend hospitalization, but the efficacy of one-stage resections in a variety of pathologies and cerebral locations is not well established. We report our center's experience with single-stage epilepsy surgery guided by intraoperative electrocorticography (ECoG). METHODS: We retrospectively analyzed 130 consecutive patients who underwent single-stage epilepsy surgery before age 19 years and had at least a two-year follow-up. Intraoperative ECoG was available for review in 113. Patients were considered seizure-free if they were continuously Engel Class I up to the two-year postoperative mark. ECoG findings were classified according to the presence of interictal attenuation, spikes, both, or neither. Complications and hospital length of stay were evaluated. RESULTS: Eighty percent of 130 patients were seizure-free at two years. All but one had an abnormal MRI. Patients with tumor had a better seizure outcome than patients with cortical malformation. Frontal resections had worse outcome, especially among tumors. Intraoperative ECoG revealed both attenuation and spikes in 48%, attenuation only in 23%, spikes only in 20%, and neither in 9%. The complication rate was 6.9%, with no major neurological complications. The average length of stay was 5.7 nights. CONCLUSIONS: With ECoG-guided single-stage surgery, we achieved results comparable with other pediatric surgical series and with a low complication rate. An extensive two-stage approach may not be required when there is a lesion on imaging and other information is concordant, even when the MRI abnormality is subtle and unclearly delineated. Frontal foci may present a challenge because of their proximity to "eloquent" nonresectable cortex or critical structures.

A granulomatous reaction to Avitene mimicking recurrence of a medulloblastoma. Case report.

Microfibrillar collagen hemostat (MCH), also known by its trade name Avitene, is commonly used to control hemorrhage during neurosurgery. Among the documented complications associated with this agent, a granulomatous foreign body reaction is rare, having been described in the central nervous system in only one previous clinical report. In the present study, the authors report the case of a 3-year-old boy who presented with a lesion which appeared to be the recurrence of a tumor 2 months after he had undergone gross-total resection for a medulloblastoma. The patient underwent resection of the presumed recurrent tumor, but histopathological analysis of the specimen revealed a granulomatous foreign body reaction to MCH and no tumor recurrence. In addition to describing the case, the authors review the surgical literature on foreign body reactions to MCH.

Long-term control after resection and gamma knife surgery of an intracranial clear cell meningioma: case report.

Clear cell meningioma (CCM) is a rare variant of meningioma characterized by sheets of polygonal cells with clear cytoplasm, a feature attributable to its high glycogen content. Authors have described its propensity to recur and metastasize despite its benign pathological characteristics. Clinical response to radiation in these reports has varied. The authors present the case of a 7-year-old girl with a large petroclival CCM who underwent a staged subtotal resection and subsequent gamma knife surgery (GKS). Initially, the residual tumor decreased in size, but 6 years later, it had regrown (9 mm in size). A second GKS treatment was performed and the mass completely regressed without further complication. The findings in this case suggest that GKS is a safe and effective adjunct for residual and recurrent CCM after resection. The delayed recurrence also emphasizes the importance of undertaking close follow-up examination after treating this potentially aggressive variant of meningioma.

Development of a de novo cerebral arteriovenous malformation in a child with sickle cell disease and moyamoya arteriopathy. Case report.

The authors report the unique case of a 6-year-old African-American girl with sickle cell disease (SCD) and an associated moyamoya arteriopathy who developed a de novo arteriovenous malformation (AVM) of the cerebral circulation. Based on preoperative cerebral angiography, computerized tomography angiography, and magnetic resonance imaging, the incidentally discovered lesion was originally thought to be a direct arteriovenous fistula with an associated varix. At surgery, however, a 1.5-cm AVM was identified adjacent to the deep surface of the varix, and it was successfully resected. The diagnosis of cerebral AVM was then confirmed histopathologically. Based on a review of the literature, no published correlation between cerebral AVMs and SCD exists. In addition to reporting this case, the authors provide a description of AVM pathogenesis, with particular emphasis on acquired AVMs of the cerebral circulation.