Samer K. Elbabaa

Intertumoral Heterogeneity within Medulloblastoma Subgroups

While molecular subgrouping has revolutionized medulloblastoma classification, the extent of heterogeneity within subgroups is unknown. Similarity network fusion (SNF) applied to genome-wide DNA methylation and gene expression data across 763 primary samples identifies very homogeneous clusters of patients, supporting the presence of medulloblastoma subtypes. After integration of somatic copy-number alterations, and clinical features specific to each cluster, we identify 12 different subtypes of medulloblastoma. Integrative analysis using SNF further delineates group 3 from group 4 medulloblastoma, which is not as readily apparent through analyses of individual data types. Two clear subtypes of infants with Sonic Hedgehog medulloblastoma with disparate outcomes and biology are identified. Medulloblastoma subtypes identified through integrative clustering have important implications for stratification of future clinical trials.

Grade II pilocytic astrocytoma in a 3‐month‐old patient with encephalocraniocutaneous lipomatosis (ECCL): Case report and literature review of low grade gliomas in ECCL

Encephalocraniocutaneous lipomatosis (ECCL) is a rare congenital syndrome with an unknown etiology. Since 1970, around 60 cases have been reported in English literature. ECCL is usually classified by cutaneous lesions and non‐progressive intracranial or spinal lipomas; however three cases of ECCL associated with low grade glioma (LGG) have been described. We report on the fourth case of LGG in a patient with ECCL; a grade II pilocytic astrocytoma with pilomyxoid features in a 3‐month‐old male, the youngest in literature.

H3 K27M mutations are extremely rare in posterior fossa group A ependymoma

BackgroundMutations in the tail of histone H3 (K27M) are frequently found in pediatric midline high-grade glioma’s but have rarely been reported in other malignancies. Recently, recurrent somatic nucleotide variants in histone H3 (H3 K27M) have been reported in group A posterior fossa ependymoma (EPN_PFA), an entity previously described to have no recurrent mutations. However, the true incidence of H3 K27M mutations in EPN_PFA is unknown.MethodsIn order to discern the frequency of K27M mutations in histone H3 in EPN_PFA, we analyzed 151 EPN_PFA previously profiled with genome-wide methylation arrays using a validated droplet digital PCR assay.ResultsWe identified only 1 case out of 151 EPN_PFA harboring the K27M mutation indicating that histone mutations are extremely rare in EPN_PFA. Morphologically, this single mutated case is clearly consistent with an ependymoma, and the presence of the K27M mutation was confirmed using immunohistochemistry.DiscussionK27M mutations are extremely rare in EPN_PFA. Routine evaluation of K27M mutations in EPN_PFA is of limited utility, and is unlikely to have any bearing on prognosis and/or future risk stratification.

Impact of DTI tractography on surgical planning for resection of a pediatric pre-pontine neurenteric cyst: a case discussion and literature review

We report a case of a four-year-old male who presented with symptoms of brainstem compression and lower cranial nerve neuropathies. MRI revealed a large, pre-pontine mass causing brainstem compression with an uncertain intra-axial component. Using diffusion tensor imaging (DTI) tractography and other imaging modalities, we were able to confirm that the lesion was extra-axial and did not involve the corticospinal tracts. In addition, DTI tractography illustrated that corticospinal tracts were displaced to the right obligating a left-sided approach. Upon resection, the mass was identified as a pre-pontine, extra-axial neurenteric cyst (NEC), which represents a rare finding in the pediatric population. The patient ultimately did well following the drainage and resection of the cyst wall and had excellent recovery. In this paper, we discuss the pathophysiology of and treatment options for NECs and explain how DTI tractography in our case assisted in planning the surgical approach.

Vein of Galen malformation treated with the Micro Vascular Plug system: case report

This case report describes the use of the Micro Vascular Plug (MVP) system in a mural-type vein of Galen aneurysmal malformation, resulting in successful occlusion of the cerebrovascular fistula. This result was confirmed with immediate cessation in blood flow and 6-month follow-up angiography. The unique characteristics of the MVP provide potential advantages over current embolic techniques for occlusion of high-flow, fistulous, intracranial vessels such as those seen in the vein of Galen aneurysmal malformation, and may represent a valuable addition to the currently available options.

Craniofacial Approach for Anterior Skull-Base Lesions

In the field of craniofacial surgery, different surgical methods for treating skull-base lesions have evolved. A thorough understanding of the microsurgical and functional anatomy of the anterior skull base is crucial for optimal selection of surgical approach and minimizing complications. Frazell and Lewis’ observation, “The entire cribriform plate can rarely be resected without creating cerebral complications” [1], reflects the therapeutic principles generally accepted in 1963. Since then, innovative and aggressive surgical techniques evolved because of the high rate of failure and complications following radiation therapy for nonresectable tumors in this area. Improved survival rates stemmed from the realization that en bloc resection of the tumor in the ethmoidal roof or cribriform plate area is possible only through a combined transcranial and facial approach [2]. Smith and colleagues [3] first described the combined facial and intracranial tumor resection for frontal sinus tumors. Dandy [4] and Ray and McLean [5] set the stage for surgical possibilities in the skull-baseareawhentheydescribedacombinedintracranialorbitalapproachtoposteriororbitaltumors. In 1959, Malecki [1] described a combined approach for treatment of posterior frontal, sphenoid, and ethmoidal roof fractures [6]. In 1963, Ketcham and colleagues [7] emphasized the need for ethmoidal roof and cribriform resection of tumors in the paranasal sinuses. Derome [8] applied craniofacial resectiontechniqueswhendevelopingtransbasalsurgeryforregionsofthesphenoidandclivus.In1969,Terz andcolleagues[9]describedmodificationsforsurgeryoftumorextensionsintothepterygoidfossa.The rate of complications associated with his modifications, however, was high. Over the next 3 decades, multiplepublicationsestablishedtheusefulnessofcombinedresectiontechniquesforremovaloftumors involving the anterior cranial floor, ethmoidal roof, cribriform plate, or orbital roof. The risk of intraoperative hemorrhage, injury to intracranial structures, and cerebrospinal fluid (CSF) leaks can largely be obviated by the combined methods. Involvement of important structures, such as the cavernous sinus, internal carotid artery, and optic nerve, however, impose the primary limitations of craniofacial resection techniques for malignant anterior cranial-base lesions [2]. In the past decade, using endoscopy and endoscope-assisted microsurgery has evolved for the treatment of selected pathologies of the skull base, primarily in the sellar and suprasellar regions. The endonasal transsphenoidal approach permits the exposure and removal of sellar and selected suprasellar lesions without the need for brain retraction [10].

Endoscope-Assisted Trans-Maxillo-Sphenoidal Approach to Sellar and Parasellar Regions: Anatomic Study.

BACKGROUND Anterolateral skull base surgery in the sellar and parasellar regions has always represented a technical challenge for neurosurgeons. The microscopic endoscope-assisted transmaxillosphenoidal approach (MEMSA) affords a direct surgical corridor free from critical skull base structures. Here we describe and critically evaluate the use of MEMSA to access the sellar and parasellar areas, in terms of surgical exposure and operability. METHODS Six cadaveric heads were examined. A stepwise dissection using MEMSA was performed. Relevant anatomy and surgical technique were critically described and comparatively reviewed. The operability score was applied for quantitative analysis of surgical operability. RESULTS MEMSA provides wide bilateral surgical exposure and vascular control of the sellar, suprasellar, and parasellar regions, achieving the highest operability on the midline and in the parasellar region. The approach can be tailored to the lesion, with the surgical corridor easily widened toward the contralateral pterygopalatine fossa. Anatomic knowledge of maxillary sinus landmarks is key to the use of this approach. Favorable sphenoidal anatomy is the main limiting factor, making MEMSA a surgical alternative to endoscopic endonasal routes in situations where those routes are not feasible, and the approach of choice in selected cases of primarily sellar lesions widely extending contralaterally to the approached maxillary sinus. CONCLUSIONS MEMSA is a safe and effective technique that provides access to the sellar, suprasellar, and contralateral parasellar areas via a direct, minimally disruptive surgical corridor. The preservation of nasal anatomy ensures the availability of mucosal flaps for use in further reconstruction.

Endoscope-Assisted Transmaxillosphenoidal Approach to the Sellar and Parasellar Regions: An Anatomic Study

BACKGROUND Anterolateral skull base surgery in the sellar and parasellar regions has always represented a technical challenge for neurosurgeons. The microscopic endoscope-assisted transmaxillosphenoidal approach (MEMSA) affords a direct surgical corridor free from critical skull base structures. Here we describe and critically evaluate the use of MEMSA to access the sellar and parasellar areas, in terms of surgical exposure and operability. METHODS Six cadaveric heads were examined. A stepwise dissection using MEMSA was performed. Relevant anatomy and surgical technique were critically described and comparatively reviewed. The operability score was applied for quantitative analysis of surgical operability. RESULTS MEMSA provides wide bilateral surgical exposure and vascular control of the sellar, suprasellar, and parasellar regions, achieving the highest operability on the midline and in the parasellar region. The approach can be tailored to the lesion, with the surgical corridor easily widened toward the contralateral pterygopalatine fossa. Anatomic knowledge of maxillary sinus landmarks is key to the use of this approach. Favorable sphenoidal anatomy is the main limiting factor, making MEMSA a surgical alternative to endoscopic endonasal routes in situations where those routes are not feasible, and the approach of choice in selected cases of primarily sellar lesions widely extending contralaterally to the approached maxillary sinus. CONCLUSIONS MEMSA is a safe and effective technique that provides access to the sellar, suprasellar, and contralateral parasellar areas via a direct, minimally disruptive surgical corridor. The preservation of nasal anatomy ensures the availability of mucosal flaps for use in further reconstruction.

Life-threatening neonatal epidural hematoma caused by precipitous vaginal delivery.

Patient: Male, 0 Final Diagnosis: Epidural hematoma Symptoms: Apnea Medication: — Clinical Procedure: Craniotomy Specialty: Pediatrics and Neonatology Objective: Unusual clinical course Background: Neonatal in-hospital falls occur relatively frequently, although they are likely underreported. Significant intracranial head trauma from a fall or birth injury is not common in the immediate newborn period. Furthermore, intracranial bleeding requiring surgical intervention is exceedingly rare. We present an unusual case of an inhospital fall in the delivery room requiring neurosurgical intervention. Case Report: A term infant, appropriate for gestational age, delivered precipitously from a maternal standing position. The vertex neonate struck the linoleum floor after an approximate 80-cm fall, landing headfirst. The physical and neurological exams were initially normal, and skull films did not demonstrate an obvious fracture. The baby was closely observed, undergoing continuous cardiorespiratory monitoring. After the patient had an episode of apnea, a scalp hematoma was noted. A computed tomography (CT) scan revealed a left parietal fracture with an acute epidural hematoma, which required emergent craniotomy. The infant had an unremarkable post-operative course and had a normal neurodevelopmental assessment at 15 months of age. Conclusions: Close, continuous observation is recommended for infants following an in-hospital fall or after significant birth trauma. A high degree of suspicion for intracranial hemorrhage must be maintained. Fall prevention strategies should focus on careful baby handling by the convalescing mother.

Holocord syringomyelia secondary to tethered spinal cord associated with anterior sacral meningocele and tailgut cyst: case report and review of literature.

Background and importanceAnterior sacral meningoceles are lesions that are uncommonly reported and can be associated with other pathology including presacral masses, tethered spinal cord, and syringomyelia. Tethered spinal cord and syringomyelia can result in neurologic deficits, while large meningoceles and presacral masses can have gastroenterologic, urologic, reproductive, and oncologic consequences.Clinical presentationThe authors report a case of a 14-year-old girl with an anterior sacral meningocele, tailgut cyst, and tethered cord with holocord syringomyelia who presented with a tethered cord syndrome, manifested by constipation, urinary retention, bilateral lower extremity weakness, and sensory deficits. After extensive radiographic and urodynamic workups were performed, the patient was treated by the neurosurgery and pediatric surgery teams with a posterior sagittal approach for cord detethering, resection of an intradural cystic mass, resection of the anterior sacral meningocele, and resection of the adjacent presacral mass. After surgical treatment, motor weakness and sensory deficits were resolved, though urinary symptoms persisted. The syrinx resolved after detethering alone. Pathology of the intradural cystic mass and the presacral mass inferior to the anterior sacral meningocele were consistent with tailgut cyst.ConclusionThe patient’s clinical and surgical management are discussed, and a literature review related to anterior sacral meningoceles and their related pathologies is presented. An interdisciplinary approach is required for the best treatment of this constellation of findings.