Infratentorial Compartment Research Articles

Immersive Surgical Anatomy of the Venous Drainage and Meningeal Supply of the Posterior Fossa: Anatomical Nuances and Microsurgical Management of Dural Arteriovenous Fistulas (dAVFs).

Dural arteriovenous fistulas (dAVFs) are anomalous connections between arteries and veins within the dura mater, involving dural sinuses, bridging veins, or emissary veins. If untreated, these lesions can result in intracranial hemorrhage. The management of posterior fossa dAVFs is challenging due to the intricate venous anatomy near the brainstem and cranial nerves. This study leverages three-dimensional (3D) technology combined with dissections to understand the anatomy and microsurgical techniques for treating infratentorial dAVFs.Five embalmed heads and one dry skull were used to meticulously document the pertinent anatomy of the infratentorial compartment. Advanced 3D technology, including 3D sculpting and structured light scanning, was employed to constructhigh-resolution volumetric models (VMs). Two-dimensional (2D) images of dissections and VMs illustrate key anatomical landmarks of the posterior fossa.Infratentorial dAVFs primarily involve sinuses, which are divided into groups based on their location: basal, medullary, and petrosal. Most of the arterial supply originates from the external carotid artery, especially the ascending pharyngeal artery. This is followed by meningeal branches from the internal carotid artery (ICA) and vertebrobasilar system. The surgical approaches to treat infratentorial dAVFs include the retrosigmoid and far lateral approaches and their modifications. Our study describes the relevant vascular anatomy of the infratentorial compartment, focusing on the surgical treatment of infratentorial dAVFs. In conjunction with the included interactive models, this study improves our educational capabilities regarding the intricate vascular neuroanatomical features of this region. When applied to a clinical setting, precise anatomical knowledge and VMs tools enhance surgical outcomes, reduce complications, and ultimately improve patient care.

Variations of Tentorial Notch Anatomy in Autopsy and NCCT of Head Injury Patients to Correlate Its Impact over Brainstem—An Observational Study

Abstract Background Tentorium cerebelli divide cranial cavity into supratentorial and infratentorial compartment. Tentorial notch is a gap in tentorium cerebelli located centrally and anteriorly, related to upper brainstem, first six cranial nerves, cerebrum, and cerebellum. The aim of this study was to analyze morphometric variation in tentorial notch anatomy in autopsy and computed tomography (CT) of head injury patients and to find out correlation between tentorial notch anatomy and uncal herniation and changes over brainstem surface in case of uncal herniation. Materials and Methods Autopsy examination of head injury patients was done between July 1, 2021, and Jan 31, 2023. Skull was opened in a standard manner and midbrain sectioned at the level of tentorial edge. Tentorial notch parameters (anterior notch width, maximum notch width, notch length, posterior tentorial length, apicotectal distance, interpedunculoclival distance) were measured using geometry compass and vernier caliper. These parameters were also measured on noncontrast computed tomography (NCCT) head of same patients. Evidence of uncal herniation was sought for in both NCCT head and autopsy examination. Impact of uncal herniation over brainstem in form of indentation over lateral surface of midbrain and macroscopic brainstem hemorrhage was noted. Results In 65 autopsy cases, there were 56 male and 9 female specimens; their mean age was 40.63 ± 16.78 years (range: 7–86 years). The most frequent type of tentorial notch observed in our study was typical type (32.30%). Relative frequency of uncal herniation was present predominantly (75%) in large type of tentorial notch and least (20%) in small type of tentorial notch. A significant correlation (p-value < 0.01) was found between uncal herniation and indentation over lateral surface of midbrain, while no significant correlation (p-value > 0.05) was found between uncal herniation and macroscopic brainstem hemorrhage in autopsy specimens. Conclusion The results of our study provide a baseline data about tentorial notch anatomy and it may facilitate neurosurgical decision making as well as help in deciding the best trajectory for lesions approaching in the vicinity of the tentorial notch

Computed tomography and magnetic resonance imaging findings in central nervous system listeriosis.

To describe the imaging findings and determine the incidence of a characteristic worm-like pattern along the white matter tracts in neurolisteriosis on CT/MRI. An IRB-approved retrospective study in 21 consecutive neurolisteriosis cases during January 2002-July 2020. At least one of the following is required: (1) Positive Listeria monocytogenes (LM) in blood with clinical signs of meningeal irritation and/or abnormal CSF profile, (2) positive LM in blood with signs of encephalitis, (3) positive LM in CSF, (4) positive LM from brain biopsy/aspiration. Six cases were excluded due to the lack of contrast-enhanced images, leaving a total of 15 cases for analysis (mean age 53.5years ± 18.8 SD). The imaging studies were independently reviewed by two blinded readers. Demographic data, imaging findings, and incidence of the worm-like pattern were reported. The Cohen's kappa was used to calculate interrater reproducibility. Of the 12 patients with relevant imaging findings, nine cases (75%) had parenchymal lesions (eight cases in supratentorial compartment and one case in infratentorial compartment), four cases (33.3%) had leptomeningeal enhancement and two cases (16.7%) had hydrocephalus. Brain abscesses were found in eight cases and nodules evocative of abscess in one case. Restricted diffusion in the central area and hemosiderin deposition were observed in all cases. The involvement of white matter tract in a worm-like pattern was demonstrated in eight of nine patients with parenchymal lesions (88.9%). Abnormal findings in brain CT/MRI images are common in neurolisteriosis. The incidence of worm-like spread along the white matter tracts is high and may help diagnose suspicious patients.

Link between both infratentorial and supratentorial intracranial pressure burdens and final outcome in patients with infratentorial brain injury.

Increased intracranial pressure (ICP) is most likely not being transmitted uniformly within the cranium. The ICP profiles in the supra- and infratentorial compartments remain largely unclear. Increased ICP in the cerebellum, however, is insufficiently captured by supratentorial ICP (ICPsup) monitoring due to compartmentalization through the tentorium. The authors hypothesized that additional infratentorial ICP (ICPinf) monitoring can be clinically valuable in selected patients. The aims of this study were to demonstrate the safety and feasibility of ICPinf monitoring and to investigate the influence of the ICPinf on clinical outcome in a real-world setting. Fifteen consecutive patients with posterior fossa (PF) lesions requiring surgery and anticipated prolonged neurointensive care between June 2019 and December 2021 were included. Simultaneous ICPsup and ICPinf were recorded. ICP burden was defined as a 15-minute interval with a mean ICP > 22 mm Hg. The Glasgow Outcome Scale score was assessed after 3 months. The mean ICPinf was substantially higher compared with ICPsup throughout the entire period of ICP recording (16.08 ± 4.44 vs 10.74 ± 3.6 mm Hg, p < 0.01). ICPinf was significantly higher in patients with unfavorable outcome when compared with those with favorable outcome (mean 17.2 ± 4.1 vs 11.4 ± 3.5 mm Hg, p < 0.05). Patients with unfavorable outcome showed significantly higher ICPinf burden compared with those with favorable outcome (mean 40.6 ± 43.8 vs 0.3 ± 0.4 hours, p < 0.05). Neither absolute ICPsup nor ICPsup burden was significantly associated with unfavorable outcome (p = 0.13). No monitoring-associated complications occurred. Supplementary ICPinf monitoring is safe and reliable. There is a significant transtentorial pressure gradient within the cranium showing elevated ICPs in the PF. Elevated ICP levels in the PF were strongly associated with unfavorable neurological outcome irrespective of ICPsup values.

Quartet of catastrophe: Bilateral epidural hematoma in both supratentorial and infratentorial compartments – A case report and a novel surgical technique to approach

Background: Epidural hematoma (EDH) is the most common form of traumatic brain lesion in the posterior fossa. This condition is rapidly fatal if not identified and treated accordingly, due to the proximity of the brain stem. Prompt diagnosis is made by early computed tomography (CT) of the head and emergent evacuation is of utmost importance. Case Description: A 28-year-old male presented to the emergency room with complaints of headache and vomiting following a road traffic accident. CT scan revealed EDH around the transverse sinus extending into supratentorial and infratentorial compartment bilaterally. The patient was planned for emergency surgery but relatives did not give consent initially they agreed after 24 h when the patient became unconscious. A midline incision was made and a small infratentorial craniectomy with two burr holes was made bilaterally above the transverse sinus. Excellent recovery was seen following a surgical procedure. Conclusion: Posterior fossa EDH is a rare but potentially fatal entity. Bilateral extension in supratentorial and infratentorial compartments makes it a “quartet of catastrophe.” Prompt diagnosis and emergent evacuation lead to excellent recovery. Two burr holes in supratentorial compartments and a small infratentorial craniectomy can avoid sinus injury.

Combined retrosigmoid and middle fossa approach for a small, superiorly located petroclival meningioma: how I do it.

Petroclival meningiomas pose significant surgical challenges because of their deep location and complex surrounding neurovasculature. The use of multiple surgical approaches can optimize safe tumor removal from multiple anatomic compartments. We describe a patient with a growing superior petroclival meningioma centered at the posterior clinoid with extension into Meckel's cave that was successfully removed with a combined retrosigmoid and subtemporal middle fossa approach. This strategy avoided the need for anterior petrous bone drilling and tentorial splitting. A combined retrosigmoid and subtemporal middle fossa approach can provide safe access to tumors spanning the supra- and infratentorial compartments.

“A tumour registry initiative”

BackgroundPublished literature on epidemiological profile of paediatric brain tumours in India is limited. Aim: To present a retrospective analysis of the histological spectrum of 158 paediatric age group central nervous system tumours operated in a single tertiary care hospital in Coastal South India between January 2015 and December 2021. Material and methodsRetrospective analysis of the data regarding frequencies of various primary brain tumours among 158 paediatric patients (<18 years of age). The tumours were categorised according to the revised 4th edition of World Health Organization (WHO) classification of tumours of the Central Nervous system. ResultsPaediatric CNS constituted 8.5% of total intracranial tumours (158/1860) operated in the study period. The mean age of the patients was 10.2 years and a definite male predominance was noted (1.54:1) Astrocytomas, glioneuronal tumours, and neuronal tumours constituted the majority (72/158; 45.6%) followed by embryonal tumours (31/158; 19.6%) and craniopharyngiomas(24/158; 15.4%).Of the glial neoplasms majority were pilocytic and other astrocytic tumours(41.6%), followed by mixed neuroglial tumours (19.4%), diffuse high grade astrocytomas (Grade III/IV) (11.1%), diffuse low -grade astrocytomas (Grade II) (9.7%) and ependymomas (13.8%). Our series also included six meningiomas (3.8%), five germ cell tumours (3.16%), four nerve sheath tumours (2.53%), two choroid plexus tumours (1.26%), two pineal parenchymal tumours (1.26%) and one metastasis from a soft tissue sarcoma from the thigh. Supratentorial tumours (58.2%) were more common than posterior fossa (34.6%) and spinal tumours (7.6%) and visual pathway gliomas accounted for 5.6% of all our tumours. ConclusionsPaediatric central nervous system tumours are more common in boys and in the second decade of life. Astrocytomas are the most common paediatric brain tumours followed by medulloblastomas and craniopharyngiomas. Pediatric tumours affect the supratentorial compartment more often than the infratentorial compartment. The profile of paediatric brain tumours in our series is similar to that reported from other Indian centres as well as most western literature.

Autoimmune encephalitis after BBIBP-CorV (Sinopharm) COVID-19 vaccination: a case report

BackgroundVaccination is an important public health strategy; however, many neurological adverse effects are associated with COVID-19 vaccination, being encephalitis a rare manifestation.Case presentationWe present the case of a 33-year-old woman who received the first dose of the BBIBP-CorV vaccine against COVID-19 on April 4 and the second dose on April 28, 2021. Three days after receiving the second dose, she experienced a subacute episode of headache, fever, insomnia, and transient episodes of environment disconnection. We obtained negative results for infectious, systemic, and oncological causes. Brain magnetic resonance imaging showed lesions in the bilateral caudate nucleus and nonspecific demyelinating lesions at the supratentorial and infratentorial compartments. The results of the neuronal autoantibodies panel were negative. She had an adequate response to immunoglobulin and methylprednisolone; however, she experienced an early clinical relapse and received a new cycle of immunosuppressive treatment followed by a satisfactory clinical evolution.ConclusionsWe report the first case of severe encephalitis associated with BBIBP-CorV (Sinopharm) vaccination in Latin America. The patient had atypical imaging patterns, with early clinical relapse and a favorable response to corticosteroid therapy.

Infratentorial retroclival and tentorial subdural hematoma from posterior communicating artery aneurysm rupture: A case report and systematic review of literature.

The objective of this systematic review is to evaluate the pathogenesis, clinical course, and prognosis of patients who suffer from aneurysm rupture, leading to subdural hematoma (SDH) of the infratentorial space without associated subarachnoid hemorrhage (SAH). Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a literature review was conducted in PubMed and Scopus electronic databases for relevant published cases of aneurysmal SDH (AnSDH) of the infratentorial compartment without associated SAH. The presentation, treatment, clinical course, and outcome of identified cases are compiled. In addition, a patient suffering from an infratentorial SDH following aneurysm rupture is presented with an illustrative case. Three articles were identified and met inclusion criteria. All cases occurred from ruptured posterior communicating artery aneurysms. All patients arrived with a Hunt and Hess classification of 2 or less. Only one case was managed with operative aneurysm clipping and hematoma evacuation while the other three cases were managed endovascularly. There were no reported postoperative complications, vasospasm, or seizures reported. All patients had a final Modified Rankin score of 3 or less at last reported follow-up. Infratentorial AnSDH without associated SAH is an etiology rarely reported in the literature. Here, we present a case report and systematic review demonstrating a relatively benign clinical course and outcome compared to report aneurysm rupture associated with SAH or mixed SAH and SDH. Moreover, there appear to be lower rates of vasospasm and improved outcomes in patients with isolated AnSDH compared to the literature aneurysmal SAH rates.

Endoscopic Fenestration of Posterior Fossa Arachnoid Cysts

Introduction: Posterior Fossa arachnoid cysts (PFAC) are rare lesions in the childhood. Owing to the wide variety of cystic malformations within the posterior cranial fossa, PFAC have long attracted the attention of pediatric neurosurgeons because they can produce not only neurological symptons but also behaviro and learning deficts, in addition to presenting major surgical challenges. Surgical treatment is warranted in symptomatic patients. Nowadays, neuroendoscopic techniques have established themselves as the treatment of choice of these lesions.&#x0D; Patients and Methods: We present four cases of symptomatic PFAC which were treated using endoscopic neurosurgery. Endoscopic approaches were defined by the presence of hydrocephalus, and discussed in each case.&#x0D; Results : Two cases of quadrigeminal plate cysts, predominantly occupying the infratentorial compartment , one case of supracerebellar cyst and one case of cerebellopontine angle were treated with good results. However, one case of quadrigeminal plate cyst developed a communicating hydrocephalus, requiring placement of cyst-ventricle peritoneal shunt, guided by the neuroendoscope.&#x0D; Discussion and Conclusion : A literature review was performed. The clinical features, the advantages and disadvantages of several surgical treatments are discussed. Symptomatic PFAC should be treated. The relatively good results using endoscopic fenestration buttresses our use as a first-line surgery.

Multi-staged approach for safe removal of tentorial meningioma – A case report

Falcotentorial meningiomas are rare and comprise only 0.3-1.1% of all meningiomas. The choice of surgical strategy for such lesions is not straightforward. 46 year old female came to our institute with complaints of gradually intensifying headache since 3 months which had aggravated over a period of 5 days. MRI Brain with contrast was done which showed a large, well circumscribed, lobulated, midline, extra-axial lesion attached to the posterior third of the falx and the anterior lip of the tentorium. The surgical plan was to excise the infra tentorial portion, for which a Steins (supra cerebellar infra tentorial) approach was deployed. Attempts to approach the supratentorial portion by incising the tentorium were unsuccessful as the required trajectory was far too acute. The supra tentorial portion would have to be approached by a more cranial trajectory, and hence it was decided to tackle that portion at a second stage. Some tumors may not be amenable to total excision in a single sitting. This case is being reported to underline the importance of a delayed 2 stage approach to excise this complex genre of Falcotentorial meningiomas which invade the supra and infra tentorial compartments.

HGG-57. Barriers in the management of pediatric high-grade gliomas in a low-resource setting during the COVID era

INTRODUCTION: High-grade gliomas account for <5% of all pediatric brain tumors with a 20% 5-year overall survival even with maximal safe resection followed by concurrent radiotherapy and chemotherapy. Patients in low- and middle-income countries already face delays and barriers to the treatment they require. The current COVID pandemic has added unique challenges to the delivery of complex, multidisciplinary health services to these patients. METHODOLOGY AND RESULTS: We retrospectively reviewed the records of four patients, ages 2-18 years old, with histologically confirmed high-grade glioma managed in a tertiary government institution from 2020-2021. Three of the patients had a supratentorial tumor and one patient had multiple tumors located in both supra- and infratentorial compartments. Neurosurgical procedures performed were: gross total excision (1), subtotal excision (2), and biopsy (1). The tissue diagnoses obtained were glioblastoma (3) and high-grade astrocytoma (1). Two patients survived and are currently undergoing adjuvant radiotherapy and chemotherapy. The remaining two patients expired: one from hospital-acquired pneumonia and the other from COVID-19 infection. DISCUSSION: Decreased mobility due to lockdowns, the burden of requiring negative COVID-19 results before admission for surgery, reduced hospital capacity to comply with physical distancing measures, the postponement of elective surgery to minimize COVID-19 transmission, physician and nursing shortages due to infection or mandatory isolation of staff, cancellation of face-to-face outpatient clinics, and hesitation among patients and their families to go to the hospital for fear of exposure were found to be common causes of delays in treatment. Also, the redirection of health resources and other government and hospital policies to handle the COVID-19 pandemic resulted in an overall delay in the delivery of health services. In particular, the management of pediatric patients with cancers, especially high-grade gliomas, was significantly disrupted.

The central vein sign is present in most infratentorial multiple sclerosis plaques

Background and purposeThere is growing evidence supporting the presence of the central vein sign (CVS) in the supratentorial brain as an imaging biomarker for multiple sclerosis (MS) diagnosis. Recently, using optimized susceptibility-weighted angiography (SWAN-venule), we detected CVS in 86% of supratentorial white matter lesions (WMLs) in the clinical setting on images obtained in a 3T MRI scanner. Despite the relevance of the infratentorial compartment, CVS prevalence in infratentorial MS plaques has not been investigated in detail. Our objective was to determine the proportion of MS infratentorial lesions showing CVS positivity. Materials and methodsWe included subjects with MS and other brain diseases showing at least one infratentorial lesion larger than 3 mm on 3D-FLAIR. Patients were scanned in a 3T MRI scanner (GE Medical Systems, discovery-MR750), applying a comprehensive protocol including post-contrast 3D-FLAIR and SWAN-venule sequences. CVS presence was confirmed by two trained raters. ResultsThirty MRIs of subjects with MS were analyzed. One hundred and one infratentorial lesions were detected on FLAIR, and 86% were centered by a vein. Fifteen MRIs from the non-MS group were analyzed, 19 lesions were visible ion FLAIR and 16% were positive for the CVS. ConclusionsSWAN-venule detects infratentorial lesions and highlights the central vein in MS plaques at 3T MRI. As occurs in the supratentorial brain, most infratentorial lesions are perivenular.

Subacute Sclerosing Panencephalitis: Restricted Diffusion and Clinical Evolution.

Subacute sclerosing panencephalitis (SSPE) is a rare entity characterized by a protracted course and progressive neurological deterioration. We present patterns of diffusion restriction in eight cases of SSPE, a seldom described imaging attribute. A retrospective analysis was performed on the clinical and neuroimaging data obtained from records of patients with proven SSPE. Patients whose magnetic resonance imaging (MRI) showed evidence of diffusion restriction were included in the analysis. MRI was performed on 3 T and 1.5-T clinical MR systems. Imaging characteristics were reviewed and tabulated by two neuroradiologists. Eight SSPE patients (seven men, one woman; age range: 5-15 years; mean age: 11 years) diagnosed and managed at our institute were included in the analysis. Restricted diffusion was evident in the basal ganglia (n = 3), corpus callosum (n = 2), white matter (n = 2) and in bilateral middle cerebellar peduncles (MCP) (n = 2). One patient had diffusion restriction in the genu of the corpus callosum and bilateral frontal cortical white matter. None of the diffusion-restricted lesions showed contrast enhancement or susceptibility. Six cases fulfilled the diagnostic criteria for fulminant SSPE (fSSPE). The extent of neuroparenchymal involvement was greater in this subset of patients. Restricted diffusion in SSPE, hitherto infrequently described, can indeed occur in both grey and white matter structures and in both supratentorial and infratentorial compartments. Parenchymal diffusion restriction in SSPE possibly reflects an early time point in the clinical evolution. A greater extent of parenchymal diffusion restriction may portend a rapid downhill course, possibly qualifying for fSSPE.

Molecular Classification and Therapeutic Targets in Ependymoma.

Simple SummaryMolecular characterization of ependymoma has revolutionized its categorization. This new molecular classification has implications particularly in targeted therapeutics. Amongst the ten subgroups of ependymoma currently described, three are found in the spinal compartment, and three in the infratentorial and supratentorial compartments respectively; the subependymoma subgroup is found in all these anatomic compartments. Each subgroup carries unique molecular features that lead to oncogenesis and to disparities in prognosis. Here, the molecular classification, key clinical features, current understanding of tumorigenesis, and potential molecular targets for cranial and spinal ependymoma are discussed.Ependymoma is a biologically diverse tumor wherein molecular classification has superseded traditional histological grading based on its superior ability to characterize behavior, prognosis, and possible targeted therapies. The current, updated molecular classification of ependymoma consists of ten distinct subgroups spread evenly among the spinal, infratentorial, and supratentorial compartments, each with its own distinct clinical and molecular characteristics. In this review, the history, histopathology, standard of care, prognosis, oncogenic drivers, and hypothesized molecular targets for all subgroups of ependymoma are explored. This review emphasizes that despite the varied behavior of the ependymoma subgroups, it remains clear that research must be performed to further elucidate molecular targets for these tumors. Although not all ependymoma subgroups are oncologically aggressive, development of targeted therapies is essential, particularly for cases where surgical resection is not an option without causing significant morbidity. The development of molecular therapies must rely on building upon our current understanding of ependymoma oncogenesis, as well as cultivating transfer of knowledge based on malignancies with similar genomic alterations.

Pediatric and Adult Low-Grade Gliomas: Where Do the Differences Lie?

Two thirds of pediatric gliomas are classified as low-grade (LGG), while in adults only around 20% of gliomas are low-grade. However, these tumors do not only differ in their incidence but also in their location, behavior and, subsequently, treatment. Pediatric LGG constitute 65% of pilocytic astrocytomas, while in adults the most commonly found histology is diffuse low-grade glioma (WHO II), which mostly occurs in eloquent regions of the brain, while its pediatric counterpart is frequently found in the infratentorial compartment. The different tumor locations require different skillsets from neurosurgeons. In adult LGG, a common practice is awake surgery, which is rarely performed on children. On the other hand, pediatric neurosurgeons are more commonly confronted with infratentorial tumors causing hydrocephalus, which more often require endoscopic or shunt procedures to restore the cerebrospinal fluid flow. In adult and pediatric LGG surgery, gross total excision is the primary treatment strategy. Only tumor recurrences or progression warrant adjuvant therapy with either chemo- or radiotherapy. In pediatric LGG, MEK inhibitors have shown promising initial results in treating recurrent LGG and several ongoing trials are investigating their role and safety. Moreover, predisposition syndromes, such as neurofibromatosis or tuberous sclerosis complex, can increase the risk of developing LGG in children, while in adults, usually no tumor growth in these syndromes is observed. In this review, we discuss and compare the differences between pediatric and adult LGG, emphasizing that pediatric LGG should not be approached and managed in the same way as adult LCG.

Supralesional Ablation Volumes Are Feasible in the Posterior Fossa and May Provide Enhanced Symptomatic Relief.

Laser interstitial thermal therapy (LITT) for posterior fossa lesions remains rare as the small size of the infratentorial compartment, proximity to the brainstem, and thickness/angulation of the occipital bone creates barriers to procedural success. Furthermore, evaluation of the effect of ablation volume on outcomes is limited. To analyze our institutional experience with LITT in the posterior fossa stratifying perioperative and long-term outcomes by ablation volumes. Seventeen patients with posterior fossa lesions treated with LITT from 2013 to 2020 were identified. Local progression-free survival (PFS), overall survival, steroid dependence, and edema reduction were evaluated with Kaplan-Meier analysis grouped by ablation volume. Preoperative, postoperative, and last known Karnofsky Performance Status (KPS) were compared using a matched paired t test. No differences in pathology, preoperative KPS, or preoperative lesion volume were found between patients with total (100%-200% increase in pre-LITT lesion volume) versus radical (>200% increase in pre-LITT lesion volume) ablations. Patients who underwent radical ablation had a higher postoperative KPS (93 vs 82, P=.02) and higher KPS (94 vs 87, P=.04) and greater reduction in perilesional edema at last follow-up (P=.01). Median follow-up was 80.8 wk. Despite obvious anatomical challenges, our results demonstrate that radical ablations are both feasible and safe in the posterior fossa. Furthermore, radical ablations may lead to greater decreases in perilesional edema and improved functional status both immediately after surgery and at last follow-up. Thus, LITT should be considered for patients with otherwise unresectable or radioresistant posterior fossa lesions.

Maternal embryonal leucine zipper kinase immunoreactivity in atypical teratoid/rhabdoid tumors: a study of 50 cases.

Atypical teratoid/rhabdoid tumors (AT/RTs) are aggressive embryonal neoplasms of the central nervous system that correspond to WHO grade IV and have a dismal prognosis. The latest Central Brain Tumor Registry of the United States data shows that AT/RT constitutes 16.6% of all embryonal tumors in children. The molecular hallmark of this tumor is pathogenic SMARCB1 genetic alterations resulting in the loss of INI-1 immunopositivity, with fewer tumors harboring SMARCA4 (BRG1) variants. Maternal embryonal leucine zipper kinase (MELK) is a member of the Snf1/AMPK family of serine/threonine-protein kinases involved in various processes such as cell cycle regulation, self-renewal of stem cells, apoptosis, and splicing regulation. Recent studies have highlighted the involvement of MELK in AT/RT and its possible therapeutic role.The purpose of this study was to review the histological and immunohistochemical profile of AT/RT with special reference to MELK staining.In this retrospective study conducted over 6years, all diagnosed cases of AT/RT, defined by loss of INI-1 immunopositivity, were retrieved and studied. Demographic details of patients and microscopic findings were analyzed, with special attention to histological patterns and immunohistochemistry profile including MELK immunoreactivity.There were 50 cases of AT/RT diagnosed in the specified period. Of the cases operated at our institute during this period, embryonal tumors constituted 20.6% of all pediatric brain tumors with AT/RT representing 12.6% of this subset. The median age at presentation was 3.5years (range: 8months-22years) and there were three adult cases. Males outnumbered females by a ratio of 1.94:1. Tumor location was distributed equally between the supratentorial and infratentorial compartments. Characteristic rhabdoid cells were identified in 70% of cases. Areas with epithelial, mesenchymal, and undifferentiated tumor cells were seen in 8%, 20%, and 52% of cases, respectively. Cells with vacuolated cytoplasm were noted in 28% of cases. Immunohistochemistry (IHC) showed a polyimmunophenotypic profile with immunopositivity for GFAP in 70%, Vimentin in 100%, SMA in 68%, and EMA in 88% of cases, indicating the remarkable heterogeneity of the tumor cells. MELK immunopositivity was noted in 83.33% of cases.Thus,atypical teratoid/rhabdoid tumors are rare neoplasms. In line with other studies, we show that these tumors occur predominantly in very young children and display marked variability on histology and IHC with loss of INI-1. MELK is presumed to be an important molecule involved in cell cycle regulation, proliferation, and other critical functions. High expression of MELK in AT/RT may suggest its plausible role in neoplastic transformation of embryonic and postnatal multipotent neural progenitors which in turn could explain the diverse morphological and immunohistochemical characteristics observed in these tumors.

Extreme lateral supracerebellar infratentorial approach for tentorial arteriovenous fistula associated with a giant venous ectasia: how I do it

BackgroundSurgery of tentorial dural arteriovenous fistulas (DAVF) associated with large ectatic vein remains challenging due to the intimate neurovascular relationships in the incisural space. Interruption of the arterialized vein requires a good knowledge of the regional anatomy and a precise preoperative evaluation.MethodsWe describe the key steps extreme lateral supracerebellar infratentorial (ELSI) approach for tentorial DAVF with a video illustration. The surgical anatomy is described along with the advantages and limitations of this approach.ConclusionsIn cases of tentorial DAVF where the foot of the arterialized vein is located in the infratentorial compartment, ELSI offers good surgical exposure and outcomes.

MRI characteristics of intracranial masses in the paediatric population of KwaZulu-Natal: A neuroimaging-based study.

BackgroundMRI is the imaging modality of choice for the assessment of intracranial masses in children. Imaging is vital in planning further management.ObjectivesThe purpose of this study was to describe the common intracranial masses and their imaging characteristics in the paediatric population referred to Inkosi Albert Luthuli Central Hospital for MRI of the brain.MethodWe retrospectively reviewed the medical records of paediatric patients (aged from birth to 18 years) who underwent MRI investigations for intracranial masses between January 2010 and December 2016.ResultsA total of 931 MRI brain scans were performed. One hundred and seven scans met the inclusion criteria, of which 92 were primary brain tumours and 15 were inflammatory masses. The majority were females (56%). The mean age was 12 ± 4.52 (range of 3–18 years). The most common presenting symptom was seizures (70/107, 65.4%). We categorised the masses according to supra- and infratentorial compartments. The most common site for masses was the supratentorial compartment (n = 56, 52%). The most common masses in the supratentorial compartment were craniopharyngiomas (14/45, 31.1%), whilst in the infratentorial compartment, the most common masses were medulloblastomas (24/47, 51.1%).ConclusionIn our series, the supratentorial compartment was the commonest site for intracranial masses. The most common tumour in the infratentorial compartment was medulloblastoma. This information is vital in formulating differential diagnoses of intracranial masses.