Cavernous Malformation Surgery in the United States: Validation of a Novel International Classification of Disease, 10th Edition, Clinical Modification Code Search Algorithm and Volume-Driven Surgical Outcomes

OBJECTIVE

The surgical decision-making process for cavernous malformation (CM) must weigh the risks of surgery against the burden of patient symptoms/hemorrhage and anticipated natural history. Here, we sought to internally validate an International Classification of Disease (ICD)-10 search algorithm for CM surgery to use to analyze a nationwide administrative database.

METHODS

Institutional records were accessed to test the validity of a novel ICD-10 search algorithm for CM surgery. The algorithm identified patients with positive predictive value (92%), specificity (100%), and sensitivity of 55%. The algorithm was applied to extract our target population from the Nationwide Readmissions Database. Univariate and multivariable analyses were used to identify factors influencing patient outcomes.

RESULTS

We identified 1235 operations for supratentorial (87%) or infratentorial (13%) CM surgery from the Nationwide Readmissions Database (2016-2017). The overall rate of adverse disposition and 30-day readmission were 19.7% and 7.5%, respectively. The rate of adverse disposition was significantly higher for infratentorial (vs. supratentorial cases) (34.3% vs. 17.6%, P = 0.001) and brainstem (vs. cerebellar) cases (55% vs. 28%, P = 0.03). Hospital case-volume percentile was associated with decreasing rates of adverse disposition (1-74th: 22%, 75th: 16%, 90th: 13%, 95th: 7%). Treatment at HVCs was also associated with shorter average length of stay (4.6 vs. 7.3 days, P < 0.001) without significant changes to average cost of hospitalization (P = 0.60).

CONCLUSIONS

Our ICD-10 coding algorithm reliably identifies CM surgery with minimal false positives. Outcomes were influenced by patient age, clinical presentation, location of CM, and experience of institution. Centralization of care may improve outcomes and warrants further investigation.

Intracranial Solitary Fibrous Tumor of the Skull Base: 2 Cases and Systematic Review of the Literature

BACKGROUND

Intracranial solitary fibrous tumors (ISFTs) are rare neoplasms of mesenchymal origin that originate from the meninges. ISFTs of the skull base can be challenging to treat, as resection can be complicated by skull base anatomy. We present 2 cases of ISFT, the first manifesting with compressive cranial neuropathy from Meckel cave involvement and the second a posterior fossa lesion causing symptomatic hydrocephalus.

METHODS

A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The PubMed database was queried with title/abstract keywords "intracranial," "solitary fibrous tumor," "hemangiopericytoma," "SFT," and "HPC." Search results were reviewed to exclude cases not involving the skull base. References from all selected articles were reviewed for potential additional cases. Patient demographic and clinical data from 58 identified skull base cases were collected for qualitative synthesis.

RESULTS

Visual disturbances were the most common presenting symptom (30 cases, 52%) followed by headache (22 cases, 38%). The most common site of involvement was the sellar/parasellar region (18 cases, 31%) followed by middle fossa/temporal bone (14 cases, 24%). Resection was performed in 55 cases; gross total resection was reported in 26 cases (45%) and subtotal resection was reported in 21 cases (36%). Tumor recurrence was documented in 15 cases (26%) with median and mean follow-up periods of 16 and 29.9 months, respectively.

CONCLUSIONS

We discuss presentation, imaging, histopathology, and management considerations for ISFTs while highlighting the potentially complex nature of skull base lesions and need for multidisciplinary approach to treatment.

Fully Endoscopic Resection of an Epidermoid Cyst of the Cerebellopontine Angle: Bilateral Resection via a Unilateral Approach

BACKGROUND AND IMPORTANCE

Epidermoid cysts are rare, benign intracranial neoplasms that typically arise at the cerebellopontine angle (CPA) and can be extensive lesions that intricately involve many critical neurovascular structures. We describe the case of a patient who presents with the classic picture of CPA epidermoid cyst and describe the value of the 4K endoscope for resection, which is illustrated in our accompanying surgical video.

CLINICAL PRESENTATION

The patient presents with headache, nausea, and vomiting accompanied by dizziness and balance issues. Radiographic imaging demonstrated a large lesion highly consistent with epidermoid cyst which involved the left CPA, encircled the basilar artery, and extended to the opposite side. Surgery was planned with a small left-sided retrosigmoid craniotomy with use of a 2-dimensional 4K endoscope to aid in resection, particularly of the contralateral side. This approach was successful with gross total resection apparent at 14-mo follow-up.

CONCLUSION

We describe the use of a fully endoscopic technique from a unilateral approach for resection of a lesion that extended in the CPA bilaterally. Additionally, we highlight the relevant neuroanatomical and neurovascular structures in this highly critical intracranial region which is well-visualized through endoscopy in the associated surgical video.

Ambulatory neurosurgery in the COVID-19 era: patient and provider satisfaction with telemedicine

OBJECTIVE

Telemedicine has rapidly expanded in the recent years as technologies have afforded healthcare practitioners the ability to diagnose and treat patients remotely. Due to the COVID-19 pandemic, nonessential clinical visits were greatly limited, and much of the outpatient neurosurgical practice at the authors' institution was shifted quickly to telehealth. Although there are prior data suggesting that the use of telemedicine is satisfactory in other surgical fields, data in neurosurgery are limited. This study aimed to investigate both patient and provider satisfaction with telemedicine and its strengths and limitations in outpatient neurosurgery visits.

METHODS

This quality improvement study was designed to analyze provider and patient satisfaction with telemedicine consultations in an outpatient neurosurgery clinic setting at a tertiary care, large-volume, academic center. The authors designed an 11-question survey for neurosurgical providers and a 13-question survey for patients using both closed 5-point Likert scale responses and multiple choice responses. The questionnaires were administered to patients and providers during the period when the clinic restricted in-person visits. At the conclusion of the study, the overall data were analyzed qualitatively and quantitatively.

RESULTS

During the study period, 607 surveys were sent out to patients seen by telehealth at the authors' academic center, and 122 responses were received. For the provider survey, 85 surveys were sent out to providers at the authors' center and other academic centers, and 40 surveys were received. Ninety-two percent of patients agreed or strongly agreed that they were satisfied with that particular telehealth visit. Eighty-eight percent of patients agreed that their telehealth visit was more convenient for them than an in-person visit, but only 36% of patients stated they would like their future visits to be telehealth. Sixty-three percent of providers agreed that telehealth visits were more convenient for them than in-person visits, and 85% of responding providers stated that they wished to incorporate telehealth into their future practice.

CONCLUSIONS

Although the authors' transition to telehealth was both rapid and unexpected, most providers and patients reported positive experiences with their telemedicine visits and found telemedicine to be an effective form of ambulatory neurosurgical care. Not all patients preferred telemedicine visits over in-person visits, but the high satisfaction with telemedicine by both providers and patients is promising to the future expansion of telehealth in ambulatory neurosurgery.

Virtual education in neurosurgery during the COVID-19 pandemic

OBJECTIVE

Neurosurgical education in the US has changed significantly as a consequence of the novel coronavirus (COVID-19) pandemic. Institutional social distancing requirements have resulted in many neurosurgical programs utilizing video conferencing for educational activities. However, it is unclear how or if these practices should continue after the pandemic. The objective of this study was to characterize virtual education in neurosurgery and understand how it should be utilized after COVID-19.

METHODS

A 24-question, 3-part online survey was administered anonymously to all 117 US neurosurgical residency programs from May 15, 2020, to June 15, 2020. Questions pertained to the current use of virtual conferencing, preferences over traditional conferences, and future inclinations. The Likert scale (1 = strongly disagree, 3 = neutral, 5 = strongly agree) was used. Comparisons were calculated using the Mann-Whitney U-test. Statistical significance was set at 0.05.

RESULTS

One-hundred eight responses were recorded. Overall, 38 respondents (35.2%) were attendings and 70 (64.8%) were trainees. Forty-one respondents (38.0%) indicated attending 5–6 conferences per week and 70 (64.8%) attend national virtual conferences. When considering different conference types, there was no overall preference (scores < 3) for virtual conferences over traditional conferences. In regard to future use, respondents strongly agreed that they would continue the practice at some capacity after the pandemic (median score 5). Overall, respondents agreed that virtual conferences would partially replace traditional conferences (median score 4), whereas they strongly disagreed with the complete replacement of traditional conferences (median score 1). The most common choices for the partial replacement of tradition conferences were case conferences (59/108, 55%) and board preparation (64/108, 59%). Lastly, there was a significant difference in scores for continued use of virtual conferencing in those who attend nationally sponsored conferences (median score 5, n = 70) and those who do not (median score 4, n = 38; U = 1762.50, z = 2.97, r = 0.29, p = 0.003).

CONCLUSIONS

Virtual conferences will likely remain an integral part of neurosurgical education after the COVID-19 pandemic has abated. Across the country, residents and faculty report a preference for continued use of virtual conferencing, especially virtual case conferences and board preparation. Some traditional conferences may even be replaced with virtual conferences, in particular those that are more didactic. Furthermore, nationally sponsored virtual conferences have a positive effect on the preferences for continued use of virtual conferences.

Effects of Preoperative Embolization on Juvenile Nasopharyngeal Angiofibroma Surgical Outcomes: A Study of the Kids' Inpatient Database

Objectives The aim of the study is to evaluate the effect of preoperative vascular embolization (PVE) on juvenile nasopharyngeal angiofibroma (JNA) surgical outcomes using a national pediatric hospitalization database.

Methods The health care cost and utilization project Kids' Inpatient Database was queried for all cases of operative management of JNA between the years of 1997 and 2016. Cases were stratified based on whether the patient received PVE. A multiple linear regression was used to predict the effect of PVE on hospital length of stay (LOS) and total cost while controlling for patient demographic factors and comorbidities. The odds ratio (OR) of receiving a perioperative blood transfusion was computed using a binary logistic regression for PVE patients.

Results A total of 473 patients who underwent JNA surgical resection in this time period were identified. The use of PVE has increased from 0% in 1997 to 66% of all cases by 2016. PVE was found to decrease LOS by 1 day (p = 0.036) and decrease the odds of needing a perioperative blood transfusion (OR = 0.511, p = 0.041). Patients receiving PVE were charged an additional $35,600 (p < 0.001), but recent data in 2016 indicate that hospital costs for PVE are decreasing.

Conclusion PVE of JNA is becoming increasingly prevalent. Embolization results in decreased hospital LOS and lower odds of needing blood transfusions. While embolization increases the cost of management, this trend should be re-evaluated as this procedure is becoming more widespread.

Paraneoplastic syndromes in small cell lung cancer

Paraneoplastic syndromes can commonly occur due to lung cancer, especially small cell lung cancer. Frequently paraneoplastic syndromes can precede the diagnosis of the neoplasm or present with limited stage disease. However, these syndromes can also occur at the time of recurrence or metastasis of disease. This review focuses on the epidemiology, pathogenesis, clinical features, and current management of the most common paraneoplastic syndromes encountered in patients with small cell lung cancer. Manifestations of paraneoplastic syndromes in small cell lung cancer include endocrine syndromes with secretion of excess hormones, and neurologic syndromes due to the production of antibodies causing an autoimmune condition. Recent advances have allowed for greater understanding of these syndromes and for the development of improved diagnostic as well as therapeutic tools. Awareness of paraneoplastic syndromes in small cell lung cancer can lead to an earlier diagnosis and recognition of both the condition and in some cases the disease potentially improving the overall survival and prognosis for patients. Further research examining effective methods to improve recovery from neurologic deficits in patients with a paraneoplastic neurologic illness is warranted.

Identification of novel fusion transcripts in meningioma

INTRODUCTION

Meningiomas are the most common primary intracranial tumor. Recent next generation sequencing analyses have elaborated the molecular drivers of this disease. We aimed to identify and characterize novel fusion genes in meningiomas.

METHODS

We performed a secondary analysis of our RNA sequencing data of 145 primary meningioma from 140 patients to detect fusion genes. Semi-quantitative rt-PCR was performed to confirm transcription of the fusion genes in the original tumors. Whole exome sequencing was performed to identify copy number variations within each tumor sample. Comparative RNA seq analysis was performed to assess the clonality of the fusion constructs within the tumor.

RESULTS

We detected six fusion events (NOTCH3-SETBP1, NF2-SPATA13, SLC6A3-AGBL3, PHF19-FOXP2 in two patients, and ITPK1-FBP2) in five out of 145 tumor samples. All but one event (NF2-SPATA13) led to extremely short reading frames, making these events de facto null alleles. Three of the five patients had a history of childhood radiation. Four out of six fusion events were detected in expression type C tumors, which represent the most aggressive meningioma. We validated the presence of the RNA transcripts in the tumor tissue by semi-quantitative RT PCR. All but the two PHF19-FOXP2 fusions demonstrated high degrees of clonality.

CONCLUSIONS

Fusion genes occur infrequently in meningiomas and are more likely to be found in tumors with greater degree of genomic instability (expression type C) or in patients with history of cranial irradiation.

Patient-Derived Orthotopic Xenograft (PDOX) Mouse Models of Primary and Recurrent Meningioma

BACKGROUND

Meningiomas constitute one-third of all primary brain tumors. Although typically benign, about 20% of these tumors recur despite surgery and radiation, and may ultimately prove fatal. There are currently no effective chemotherapies for meningioma. We, therefore, set out to develop patient-derived orthotopic xenograft (PDOX) mouse models of human meningioma using tumor.

METHOD

Of nine patients, four had World Health Organization (WHO) grade I tumors, five had WHO grade II tumors, and in this second group two patients also had recurrent (WHO grade III) meningioma. We also classified the tumors according to our recently developed molecular classification system (Types A, B, and C, with C being the most aggressive). We transplanted all 11 surgical samples into the skull base of immunodeficient (SCID) mice. Only the primary and recurrent tumor cells from one patient-both molecular Type C, despite being WHO grades II and III, respectively-led to the formation of meningioma in the resulting mouse models. We characterized the xenografts by histopathology and RNA-seq and compared them with the original tumors. We performed an in vitro drug screen using 60 anti-cancer drugs followed by in vivo validation.

RESULTS

The PDOX models established from the primary and recurrent tumors from patient K29 (K29P-PDOX and K29R-PDOX, respectively) replicated the histopathology and key gene expression profiles of the original samples. Although these xenografts could not be subtransplanted, the cryopreserved primary tumor cells were able to reliably generate PDOX tumors. Drug screening in K29P and K29R tumor cell lines revealed eight compounds that were active on both tumors, including three histone deacetylase (HDAC) inhibitors. We tested the HDAC inhibitor Panobinostat in K29R-PDOX mice, and it significantly prolonged mouse survival (p < 0.05) by inducing histone H3 acetylation and apoptosis.

CONCLUSION

Meningiomas are not very amenable to PDOX modeling, for reasons that remain unclear. Yet at least some of the most malignant tumors can be modeled, and cryopreserved primary tumor cells can create large panels of tumors that can be used for preclinical drug testing.

Outcomes in Pediatric Transsphenoidal Pituitary Surgery Stratified by the Use of Image Guidance: An Analysis of the Kids' Inpatient Database from 1997 to 2016

Background  To evaluate the utilization of image guidance technology for pediatric transsphenoidal pituitary resection (TSPR) and analyze the complication rates, length of stay (LOS), and total cost for such surgeries as function of time and utilization of image guidance. Methods  The Healthcare Cost and Utilization Project Kids' Inpatient Database (KID) was queried for all cases of TSPR between 1997 and 2016. Factors extracted included patient demographics, use of image guidance, LOS, total cost, and complications, including panhypopituitarism, diabetes insipidus (DI), cerebrospinal fluid (CSF) rhinorrhea, and cranial nerve (CN) III, IV, and VI palsies. Multivariate logistic regression was utilized to determine the odds ratio of developing panhypopituitarism, DI, CSF rhinorrhea, and CN palsies for image-guided versus nonimage-guided cases. A generalized linear model was used to determine the effect of image guidance on inflation-adjusted total cost and LOS. Results  A total of 1,297 cases of TSPR were included in the KID over this time period. The majority were female, Caucasian, and older than 15 years. Utilization of image guidance has rapidly increased since 2006. Complication rates were comparable, but when controlling for other factors, the use of image guidance showed a lower risk of postoperative DI ( p  = 0.05). The use of image guidance also resulted in a shorter LOS by 2.84 days ( p  < 0.001) with no associated increase in total cost ( p  = 0.663). Conclusion  The use of imaging guidance for pediatric TSPR has precipitously increased in recent years, as it is cost-effective, decreases LOS, and may lead to lower complication rates, such as DI.

Juvenile Nasopharyngeal Angiofibroma Outcomes and Cost: Analysis of the Kids’ Inpatient Database

Objective:

To report trends in Juvenile Nasopharyngeal Angiofibroma (JNA) hospitalizations and identify key factors affecting treatment outcomes and cost of care in JNA patients.

Methods:

The Healthcare Cost and Utilization Project (HCUP) Kids’ Inpatient Database was queried for all cases of JNA between the years of 1997 and 2016. Key factors extracted were patient demographics, geographic region, hospital size, teaching status, elective admissions, and number of diagnoses and procedures performed during the hospitalization. These elements were correlated to length of stay (LOS) and cost-per-day (CPD) using a multiple linear regression (MLR). Regional variation in JNA diagnosis and changes in LOS and CPD trends over time were also analyzed.

Results:

A total of 614 JNA patients were hospitalized in this time period, with a majority of patients identifying as male (98%) and Caucasian/White (55%). The average LOS has decreased by 0.14 day per year since 1997 ( P = .0034) whereas the CPD has steadily increased by $2 380 per year ( P < .001). MLR analysis revealed that while holding all other factors constant, patients who stayed at teaching hospitals had an increased LOS of 1.7 days ( P = .026), but paid $11 961 less per day ( P = .05). Regional variation in CPD was found in the Northeast region, where hospitalizations were more expensive by $9 801 per day compared to the South ( P = .017).

Conclusion:

These results indicate hospital characteristics, such as teaching status and geographic region, may predict differences in JNA outcomes and cost. Healthcare providers should be cognizant of these variations to ensure optimal patient outcomes and expenditures.

Mecp2 Deletion from Cholinergic Neurons Selectively Impairs Recognition Memory and Disrupts Cholinergic Modulation of the Perirhinal Cortex

Rett Syndrome is a neurological disorder caused by mutations in the gene encoding methyl CpG binding protein 2 (MeCP2) and characterized by severe intellectual disability. The cholinergic system is a critical modulator of cognitive ability and is affected in patients with Rett Syndrome. To better understand the importance of MeCP2 function in cholinergic neurons, we studied the effect of selective Mecp2 deletion from cholinergic neurons in mice. Mice with Mecp2 deletion from cholinergic neurons were selectively impaired in assays of recognition memory, a cognitive task largely mediated by the perirhinal cortex (PRH). Deletion of Mecp2 from cholinergic neurons resulted in profound alterations in baseline firing of L5/6 neurons and eliminated the responses of these neurons to optogenetic stimulation of cholinergic input to PRH. Both the behavioral and the electrophysiological deficits of cholinergic Mecp2 deletion were rescued by inhibiting ACh breakdown with donepezil treatment.

Operative Anatomy of the Human Skull: A Virtual Reality Expedition

INTRODUCTION

The human cranial vault possesses an incredible, complex anatomical intricacy. Bridging the divide between 2-dimensional (2D) learning resources and the 3-dimensional (3D) world in which the anatomy becomes clinically relevant poses an intellectual challenge. Advances in computer graphics and modelling technologies have allowed increasingly accurate and representative resources to supplement cadaveric dissection specimens.

OBJECTIVE

To create accurate virtual models of all cranial bones to augment education, research, and clinical endeavours.

METHODS

Through a careful analysis of osteological specimens and high-resolution radiographic studies, a highly accurate virtual model of the human skull was created and annotated with relevant anatomical landmarks.

RESULTS

The skull was divided into 6 major segments including frontal, ethmoid, sphenoid, temporal, parietal, and occipital bones. These bones were thoroughly annotated to demonstrate the intricate anatomical features.

CONCLUSION

This virtual model has the potential to serve as a valuable resource for educational, research, and clinical endeavours, and demonstrates the significance of advances in computer modelling that can contribute to our understanding of neurosurgical anatomical substrates.

The Role of Merlin/NF2 Loss in Meningioma Biology

Mutations in the neurofibromin 2 (NF2) gene were among the first genetic alterations implicated in meningioma tumorigenesis, based on analysis of neurofibromatosis type 2 (NF2) patients who not only develop vestibular schwannomas but later have a high incidence of meningiomas. The NF2 gene product, merlin, is a tumor suppressor that is thought to link the actin cytoskeleton with plasma membrane proteins and mediate contact-dependent inhibition of proliferation. However, the early recognition of the crucial role of NF2 mutations in the pathogenesis of the majority of meningiomas has not yet translated into useful clinical insights, due to the complexity of merlin's many interacting partners and signaling pathways. Next-generation sequencing studies and increasingly sophisticated NF2-deletion-based in vitro and in vivo models have helped elucidate the consequences of merlin loss in meningioma pathogenesis. In this review, we seek to summarize recent findings and provide future directions toward potential therapeutics for this tumor.

Bone Conduction Implants for Hearing Rehabilitation in Skull Base Tumor Patients

Bone conduction implants transfer sound to the inner ear through direct vibration of the skull. In patients with skull base tumors and infections, these devices can bypass a dysfunctional ear canal and/or middle ear. Though not all skull base surgery patients opt for bone conduction hearing rehabilitation, a variety of these devices have been developed and marketed over time. This article reviews the evolution and existing state of bone conduction technology.

Newly Diagnosed Optic Pathway Glioma During Pregnancy

BACKGROUND

Optic pathway gliomas (OPGs) are relatively rare, and their presentation after the first decade of life is even less common. Although many treatment options exist, surgery is typically reserved for tumors significantly compressing surrounding structures. Pregnancy can complicate the management of these tumors, as fetal developmental considerations limit the ways in which they are imaged and treated.

CASE DESCRIPTION

In this report we detail the case of a 27-year-old pregnant woman who was found to have an OPG during her third trimester. After a decline in this patient's vision and clinical status, a decision was made to induce labor at 31 weeks so that her disease could be more thoroughly addressed.

CONCLUSIONS

While OPGs are typically benign tumors, pregnancy complicates their management significantly. Contrast media and anesthesia pose significant risks to the fetus, while pregnancy may contribute to increased rates of tumor growth and clinical deterioration. Managing OPGs in pregnant patients thus requires balancing the risks to the fetus and patient.

Inability of positive phase II clinical trials of investigational treatments to subsequently predict positive phase III clinical trials in glioblastoma

Background

Glioblastoma is the most common primary malignant brain tumor in adults, but effective therapies are lacking. With the scarcity of positive phase III trials, which are increasing in cost, we examined the ability of positive phase II trials to predict statistically significant improvement in clinical outcomes of phase III trials.

Methods

A PubMed search was conducted to identify phase III clinical trials performed in the past 25 years for patients with newly diagnosed or recurrent glioblastoma. Trials were excluded if they did not examine an investigational chemotherapy or agent, if they were stopped early owing to toxicity, if they lacked prior phase II studies, or if a prior phase II study was negative.

Results

Seven phase III clinical trials in newly diagnosed glioblastoma and 4 phase III clinical trials in recurrent glioblastoma met the inclusion criteria. Only 1 (9%) phase III study documented an improvement in overall survival and changed the standard of care.

Conclusion

The high failure rate of phase III trials demonstrates the urgent need to increase the reliability of phase II trials of treatments for glioblastoma. Strategies such as the use of adaptive trial designs, Bayesian statistics, biomarkers, volumetric imaging, and mathematical modeling warrant testing. Additionally, it is critical to increase our expectations of phase II trials so that positive findings increase the probability that a phase III trial will be successful.

Highlighting the need for reliable clinical trials in glioblastoma

INTRODUCTION

Several recent phase III studies have attempted to improve the dismal survival seen in glioblastoma patients, with disappointing results despite prior promising phase II data. Areas covered: A literature review of prior phase II and phase III studied in glioblastoma was performed to help identify possible areas of concern. Numerous issues in previous phase II trials for glioblastoma were found that may have contributed to these discouraging outcomes and discordant results. Expert commentary: These concerns include the improper selection of therapeutics warranting investigation in a phase III trial, suboptimal design of phase II studies (often lacking a control arm), absence of molecular data, the use of imaging criteria as a surrogate endpoint, and a lack of pharmacodynamic testing. Hopefully, by recognizing prior phase II trial limitations that contributed to failed phase III trials, we can adapt quickly to improve our ability to accurately discover survival-prolonging treatments for glioblastoma patients.

Spinal Epidermoid Tumors: Case Report and Review of the Literature

Spinal epidermoid tumors are rare, benign tumors that are either acquired from trauma, surgery, or lumbar puncture or arise as congenital lesions, particularly spinal dysraphisms. We report a case of a massive spinal epidermoid tumor and review the literature with a focus on the surgical outcomes. A 71-year-old female patient presented after a fall with subsequent symptoms of severe back and hip pain, as well as loss of motor strength in the left leg. Her magnetic resonance imaging demonstrated a T2/short tau inversion recovery hyperintense mass extending from the level of the T10–11 disc caudally through S2. A biopsy was recommended to determine whether the tumor was radio- or chemo-sensitive. The patient underwent a L4 laminectomy and a pearly-white tumor was encountered, with a subsequent biopsy confirming it to be an epidermoid tumor. The following conclusions can be drawn from a review of the literature. Spinal epidermoid tumors are more common in women and tend to present in younger patients (median age of 23). The majority of patients had acquired lesions (46%). In terms of surgical outcomes for adherent tumors, gross total resection was found to provide optimal outcomes, with 90% of patients improving clinically after surgery.

Intracranial Erdheim-Chester Disease Mimicking Parafalcine Meningioma: Report of Two Cases and Review of the Literature

BACKGROUND

Erdheim-Chester disease (ECD) is a rare, non-Langerhans cell histiocytosis that typically occurs in middle-aged patients. It is usually characterized by multifocal osteosclerotic lesions of the long-bones, however many cases have extraskeletal involvement. Central nervous system (CNS) involvement is common, but isolated CNS involvement at presentation has rarely been reported.

CASE DESCRIPTION

Here we report two cases of dural-based ECD mimicking meningioma on imaging with no other identified sites of disease.

CONCLUSION

ECD is a rare disease, with isolated CNS involvement reported only a few times in the literature. The significance of this presentation requires additional study and long-term follow up.

Jak2-mediated phosphorylation of Atoh1 is critical for medulloblastoma growth

Treatment for medulloblastoma, the most common malignant brain tumor in children, remains limited to surgical resection, radiation, and traditional chemotherapy; with long-term survival as low as 50–60% for Sonic Hedgehog (Shh)-type medulloblastoma. We have shown that the transcription factor Atonal homologue 1 (Atoh1) is required for Shh-type medulloblastoma development in mice. To determine whether reducing either Atoh1 levels or activity in tumors after their development is beneficial, we studied Atoh1 dosage and modifications in Shh-type medulloblastoma. Heterozygosity of Atoh1 reduced tumor occurrence and prolonged survival. We discovered tyrosine 78 of Atoh1 is phosphorylated by a Jak2-mediated pathway only in tumor-initiating cells and in human SHH-type medulloblastoma. Phosphorylation of tyrosine 78 stabilizes Atoh1, increases Atoh1’s transcriptional activity, and is independent of canonical Jak2 signaling. Importantly, inhibition of Jak2 impairs tyrosine 78 phosphorylation and tumor growth in vivo. Taken together, inhibiting Jak2-mediated tyrosine 78 phosphorylation could provide a viable therapy for medulloblastoma.

Medulloblastoma is the most common solid brain tumor that develops in children, with more than five hundred new cases diagnosed in the United States every year. There are four broad types of medulloblastoma. One of these is called the “Sonic Hedgehog” subtype, named after the biological pathway that becomes re-activated in these tumors. Only about half of patients with this subtype survive for more than 10 years. Moreover, medulloblastoma treatment combines surgery, chemotherapy and radiation, which can cause severe side effects including psychiatric disorders and cognitive impairment.

Several drugs that treat medulloblastoma by targeting the Sonic Hedgehog pathway are currently being tested in clinical trials. However, these drugs are usually only effective for a limited time before the tumor evades the treatment. Therefore, there is a need to develop new treatment options for medulloblastoma, perhaps by targeting different signaling pathways in the cells.

A protein called Atoh1 is needed for proper brain development in humans, but is not normally present after the first year of life. This protein is, however, re-expressed at high levels in medulloblastoma in mice and humans and is essential for Sonic Hedgehog-type medulloblastoma to form in mice.

Klisch et al. used genetic techniques to reduce the amount of Atoh1 in mice that develop medulloblastoma. This intervention reduced the number of mice that developled tumors and increased their lifespan. Biochemical experiments showed that the tumor stem cells of the mice contain a modified version of Atoh1 where a phosphate molecule is bound to a particular region of the protein. This phosphorylation increased the amount and activity of Atoh1 in the cell, and so caused tumors to grow more quickly in mice. Phosphorylated Atoh1 was also detected in samples taken from human medulloblastoma tumors.

Klisch et al. also found that an enzyme called Jak2 phosphorylates Atoh1. Inhibiting Jak2 reduced the levels of Atoh1 in medulloblastoma cells and slowed tumor growth in mice. Future work could investigate different ways of preventing Atoh1 phosphorylation, with the hope of finding new treatments for Sonic-Hedgehog-type medulloblastomas.