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Pediatric low-grade gliomas represent the most common childhood brain tumor class. While often curable, some tumors fail to respond and even successful treatments can have life-long side effects. Many clinical trials are underway for pediatric low-grade gliomas. However, these trials are expensive and challenging to organize due to the heterogeneity of patients and subtypes. Advances in sequencing technologies are helping to mitigate this by revealing the molecular landscapes of mutations in pediatric low-grade glioma. Functionalizing these mutations in the form of preclinical models is the next step in both understanding the disease mechanisms as well as for testing therapeutics. However, such models are often more difficult to generate due to their less proliferative nature, and the heterogeneity of tumor microenvironments, cell(s)-of-origin, and genetic alterations. In this review, we discuss the molecular and genetic alterations and the various preclinical models generated for the different types of pediatric low-grade gliomas. We examined the different preclinical models for pediatric low-grade gliomas, summarizing the scientific advances made to the field and therapeutic implications. We also discuss the advantages and limitations of the various models. This review highlights the importance of preclinical models for pediatric low-grade gliomas while noting the challenges and future directions of these models to improve therapeutic outcomes of pediatric low-grade gliomas.

MEK inhibitors (MEKi) represent innovative and promising treatments for managing manifestations of neurofibromatosis type 1 (NF1). To mitigate potential ophthalmic side effects, such as MEKi-associated retinopathy (MEKAR), patients undergoing MEKi therapy routinely receive ophthalmology evaluations. Our study aims to assess the necessity of this regular screening within a predominantly pediatric NF1 population by examining the occurrence of ocular adverse events (OAE). A retrospective study evaluated 45 NF1 patients receiving MEKi. Inclusion criteria included baseline and follow-up examinations following the initiation of MEKi therapy. At each assessment, a comprehensive eye evaluation was performed, comprising a dilated fundus examination, ocular coherence tomography of the macula and nerve fiber layer, and Humphrey visual field testing. Twenty-six patients, with an average age of 13 years (range 2–23 years) and an average follow-up duration of 413 days were included in the analysis. Three different MEKi were used: selumetinib (77%), trametinib (23%), and mirdametinib (4%). None of the patients experienced retinopathy at any point during the study. Some patients had pre-existing optic neuropathies (27%), but no instances of nerve changes occurred after commencing MEKi therapy. Four patients (15%) exhibited symptoms of dry eye, all of which were effectively managed with topical lubrication.

MEK inhibitors (MEKi) represent innovative and promising treatments for managing manifestations of neurofibromatosis type 1 (NF1). To mitigate potential ophthalmic side effects, such as MEKi-associated retinopathy (MEKAR), patients undergoing MEKi therapy routinely receive ophthalmology evaluations. Our study aims to assess the necessity of this regular screening within a predominantly pediatric NF1 population by examining the occurrence of ocular adverse events (OAE). A retrospective study evaluated 45 NF1 patients receiving MEKi. Inclusion criteria included baseline and follow-up examinations following the initiation of MEKi therapy. At each assessment, a comprehensive eye evaluation was performed, comprising a dilated fundus examination, ocular coherence tomography of the macula and nerve fiber layer, and Humphrey visual field testing. Twenty-six patients, with an average age of 13 years (range 2–23 years) and an average follow-up duration of 413 days were included in the analysis. Three different MEKi were used: selumetinib (77%), trametinib (23%), and mirdametinib (4%). None of the patients experienced retinopathy at any point during the study. Some patients had pre-existing optic neuropathies (27%), but no instances of nerve changes occurred after commencing MEKi therapy. Four patients (15%) exhibited symptoms of dry eye, all of which were effectively managed with topical lubrication. [ABSTRACT FROM AUTHOR]

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Abstract Tissue injury and tumorigenesis share many cellular and molecular features, including immune cell (T cells, monocytes) infiltration and inflammatory factor (cytokines, chemokines) elaboration. Their common pathobiology raises the intriguing possibility that brain injury could create a tissue microenvironment permissive for tumor formation. Leveraging several murine models of the Neurofibromatosis type 1 (NF1) cancer predisposition syndrome and two experimental methods of brain injury, we demonstrate that both optic nerve crush and diffuse traumatic brain injury induce optic glioma (OPG) formation in mice harboring Nf1-deficient preneoplastic progenitors. We further elucidate the underlying molecular and cellular mechanisms, whereby glutamate released from damaged neurons stimulates IL-1β release by oligodendrocytes to induce microglia expression of Ccl5, a growth factor critical for Nf1-OPG formation. Interruption of this cellular circuit using glutamate receptor, IL-1β or Ccl5 inhibitors abrogates injury-induced glioma progression, thus establishing a causative relationship between injury and tumorigenesis.

Yunshuo Tang,1,2 David H Gutmann2 1Department of Ophthalmology, Washington University School of Medicine, St. Louis, MO, USA; 2Department of Neurology, Washington University School of Medicine, St. Louis, MO, USACorrespondence: David H Gutmann, Department of Neurology, Washington University School of Medicine, Box 8111, 660 S. Euclid Avenue, St. Louis, MO, 63110, USA, Tel +1 314 362 7379, Fax +1 314 362 2388, Email gutmannd@wustl.eduAbstract: Optic pathway glioma (OPG) occurs in as many as one-fifth of individuals with the neurofibromatosis type 1 (NF1) cancer predisposition syndrome. Generally considered low-grade and slow growing, many children with NF1-OPGs remain asymptomatic. However, due to their location within the optic pathway, ~20-30% of those harboring NF1-OPGs will experience symptoms, including progressive vision loss, proptosis, diplopia, and precocious puberty. While treatment with conventional chemotherapy is largely effective at attenuating tumor growth, it is not clear whether there is much long-term recovery of visual function. Additionally, because these tumors predominantly affect young children, there are unique challenges to NF1-OPG diagnosis, monitoring, and longitudinal management. Over the past two decades, the employment of authenticated genetically engineered Nf1-OPG mouse models have provided key insights into the function of the NF1 protein, neurofibromin, as well as the molecular and cellular pathways that contribute to optic gliomagenesis. Findings from these studies have resulted in the identification of new molecular targets whose inhibition blocks murine Nf1-OPG growth in preclinical studies. Some of these promising compounds have now entered into early clinical trials. Future research focused on defining the determinants that underlie optic glioma initiation, expansion, and tumor-induced optic nerve injury will pave the way to personalized risk assessment strategies, improved tumor monitoring, and optimized treatment plans for children with NF1-OPG.Keywords: neurofibromatosis type 1, optic glioma, vision loss, genetically engineered mouse models

In this paper, the authors present a clinical picture of the diagnosis and current treatment regimens of optic pathway glioma in the pediatric population, with an emphasis on the role of an ophthalmic diagnosis in the differentiation and monitoring of lesions. Glioma is the most common optic nerve tumor in children. Material: Articles in PubMed, Scholar and Website were reviewed, taking into account current standards of management related to sporadic or NF1-related optic glioma, epidemiology, location, course of the disease, clinical manifestations, histological types of the tumor, genetic predisposition, diagnostic ophthalmic tests currently applicable in therapeutic monitoring of the tumor, neurological diagnosis, therapeutic management and prognosis. The importance of current screening recommendations, in line with standards, was emphasized. Results: Glioma occurs in children most often in the first decade of life. Initially, they may be asymptomatic, and clinically ophthalmic changes are associated with the organ of vision or with systemic changes. Gliomas associated with the NF1 mutation have a better prognosis for sporadic gliomas. Diagnosis includes radiological imaging methods/MRI/ophthalmology/OCT and visual acuity log MAR assessment. The basis of treatment is clinical observation. In the case of disease progression, surgical treatment, chemotherapy and targeted therapy are used. Conclusion: Further research into novel techniques for detecting gliomas would allow for early monitoring of the disease. [ABSTRACT FROM AUTHOR]

Introduction: Optic pathway gliomas (OPGs) are associated with significant risk of visual and endocrine morbidity, but data on long-term outcomes in symptomatic patients is sparse. This study reviews the clinical course, disease progression, survival outcomes and long-term sequelae in pediatric patients with symptomatic OPGs in our institution over three decades. Methods: Retrospective review of patients with symptomatic OPG treated in a single tertiary pediatric oncology center from 1984 to 2016. Results: A total of 37 patients were diagnosed with symptomatic OPG. Decreased visual acuity was the commonest presenting symptom (75.7%). Surgical intervention was performed in 62.2%; 56.5% underwent biopsy, 26.1% surgical debulking and 17.4% had orbital decompression with cystic fenestration and cosmetic optic nerve excision at different treatment intervals. CSF diversion was performed in 47.8% patients. Histopathologic examination confirmed 86% to be pilocytic astrocytoma and 1 ganglioglioma. 46% received chemotherapy and 48% had radiotherapy, at different intervals. Median follow-up was 13.74 years. In NF1 patients, overall survival (OS) was 100% at 5 years and 55.6 ± 24.8% at 25 years while progression-free-survival (PFS) was 50 ± 15.8% at 5 and 20 years. In non-NF1 patients, OS was 96.2 ± 3.8% at 5 years and 87.4 ± 9% at 25-years. 5-year PFS was 53.8 ± 9.8% and 25-year PFS was 49.0 ± 10%. Cumulative PFS was 53 ± 8.3% at 5 years and 49.7 ± 8.4% at 20 years while cumulative OS was 97.2 ± 2.7% at 5 years and 77.5 ± 10.8% at 25 years. 59.5% patients developed postoperative endocrinopathy. Long-term vision was normal in 8.1%, improved in 13.5%, stabilized in 40.5% but worsened in 37.8% patients. Three patients treated with radiotherapy developed second brain tumors. Conclusion: 25-year OS in this cohort was 77.5% but survivorship carried significant long-term morbidities including radiation-induced second malignant brain tumors. [ABSTRACT FROM AUTHOR]

The sphenoid ridge approach (SRA) was initially described as a surgical technique for treating vascular pathologies near the Sylvian fissure. However, limited studies have systematically explored the use of skull base techniques in pediatric patients. This study investigated an extended variation in the sphenoid ridge approach (E-SRA), which systematically removed the pterion, orbital walls (roof and lateral wall), greater sphenoid wing, and anterior clinoid process to access the base of the skull. Objective: This report aimed to evaluate the advantages of the extradural removal of the orbital roof, pterion, sphenoid wing, and anterior clinoid process as a complement to the sphenoid ridge approach in pediatric patients. Patients and Methods: We enrolled 36 patients with suspected neoplastic diseases in different regions. The E-SRA was performed to treat the patients. Patients were included based on the a priori objective of a biopsy or a total gross resection. The surgical time required to complete the approach, associated bleeding, and any complications were documented. Results: Our results demonstrated that the proposed a priori surgical goal, biopsy, or resection were successfully achieved in all cases. In addition, using the E-SRA technique was associated with a shorter operative time, minimal bleeding, and a lower incidence of complications. The most frequently encountered complications were related to dural closure. Conclusions: The extended sphenoid ridge approach represents a safe and effective option for managing intracranial tumors in pediatrics. [ABSTRACT FROM AUTHOR]

IntroductionOptic pathway gliomas (OPGs) are associated with significant risk of visual and endocrine morbidity, but data on long-term outcomes in symptomatic patients is sparse. This study reviews the clinical course, disease progression, survival outcomes and long-term sequelae in pediatric patients with symptomatic OPGs in our institution over three decades.MethodsRetrospective review of patients with symptomatic OPG treated in a single tertiary pediatric oncology center from 1984 to 2016.ResultsA total of 37 patients were diagnosed with symptomatic OPG. Decreased visual acuity was the commonest presenting symptom (75.7%). Surgical intervention was performed in 62.2%; 56.5% underwent biopsy, 26.1% surgical debulking and 17.4% had orbital decompression with cystic fenestration and cosmetic optic nerve excision at different treatment intervals. CSF diversion was performed in 47.8% patients. Histopathologic examination confirmed 86% to be pilocytic astrocytoma and 1 ganglioglioma. 46% received chemotherapy and 48% had radiotherapy, at different intervals. Median follow-up was 13.74 years. In NF1 patients, overall survival (OS) was 100% at 5 years and 55.6 ± 24.8% at 25 years while progression-free-survival (PFS) was 50 ± 15.8% at 5 and 20 years. In non-NF1 patients, OS was 96.2 ± 3.8% at 5 years and 87.4 ± 9% at 25-years. 5-year PFS was 53.8 ± 9.8% and 25-year PFS was 49.0 ± 10%. Cumulative PFS was 53 ± 8.3% at 5 years and 49.7 ± 8.4% at 20 years while cumulative OS was 97.2 ± 2.7% at 5 years and 77.5 ± 10.8% at 25 years. 59.5% patients developed post-operative endocrinopathy. Long-term vision was normal in 8.1%, improved in 13.5%, stabilized in 40.5% but worsened in 37.8% patients. Three patients treated with radiotherapy developed second brain tumors.Conclusion25-year OS in this cohort was 77.5% but survivorship carried significant long-term morbidities including radiation-induced second malignant brain tumors.

Neurofibromatosis type 1 (NF1) is one of the most common genetic conditions. It can be inherited in an autosomal dominant manner, but almost half of cases occur de novo. NF1 is associated with café-au-lait macules, freckles in the inguinal and axillary region, neurofibromas, Lisch nodules of the iris or choroidal abnormalities, optic pathway gliomas, and distinctive bone anomalies. It has complete penetrance but highly variable disease manifestations. Certain features including café-au-lait macules, bony abnormalities, and optic pathway gliomas emerge by early childhood, but others appear later in life. A cure for NF1 has not been found, however emerging treatments have involved modulation of the RAS/MAPK signaling pathway. [ABSTRACT FROM AUTHOR]

Malignant optic gliomas are an uncommon pathology, with around 67 cases reported worldwide in the literature. We present the case of a 77-year-old-male with a two-month history of progressive vision loss, ultimately leading to bilateral blindness. The initial clinical suspicion was a non-inflammatory ischemic optic neuropathy. Stereotactic biopsy was performed on the optic chiasm, and the histopathological diagnosis was confirmed as Glioblastoma.

Optic neuritis and optic glioma are diseases that affect the optic nerve and cause visual disturbances. Although they can have different clinical presentations, they can also mimic each other. Optic glioma is a slow-growing tumor that causes gradual vision loss, whereas optic neuritis is an acute inflammatory disease that causes sudden onset vision loss and pain with eye movements. Due to the limitations of magnetic resonance imaging, distinguishing between the two conditions is not always possible. Herein, we have reported the case of a patient who was diagnosed with optic neuritis after extensive investigations and who recovered completely with medical treatment. [ABSTRACT FROM AUTHOR]

Copyright of Die Radiologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: Optic pathway gliomas (OPGs) constitute approximately 3–5% of childhood intracranial tumors. In this study, the authors presented their experience of using the endoscopic endonasal approach to treat patients with OPG located in the chiasma-hypothalamic region and aimed to use the infrachiasmatic corridor in the endoscopic endonasal approach as an alternative to the transcranial approach in the surgical necessity of OPGs. Methods: We retrospectively analyzed the data of ten patients diagnosed with OPG histopathologically among 3757 cases who underwent endoscopic endonasal surgery between August 1997 and March 2021 at Kocaeli University Faculty of Medicine Pituitary Research Center and Department of Neurosurgery. Mean follow-up period 48.5 months. During the postoperative follow-up period, 3 of these 10 patients underwent reoperation due to tumor recurrence. Combined (endoscopic endonasal approach + transcranial approach) approach was applied to 2 patients in the same session. Surgical and clinical outcomes were evaluated in detail. Results: Ten patients with a mean patient age of 20.6 ± 11.4 were included in this study. The most common complaint was visual impairment. After surgery, improvement in visual impairment was observed in five patients. No increase in postoperative visual impairment was observed in any of the patients. Postoperative panhypopituitarism was not observed in any of the patients. STR resection was performed in 5 patients and NTR resection in 5 patients. No additional treatment was required during follow-up in 4 of 5 patients who underwent NTR. A total of 6 patients received postoperative radiotherapy treatment. Conclusions: In gliomas located in the chiasma-hypothalamic region, appropriate patient selection and endoscopic endonasal surgical treatment may contribute to the elimination of symptoms due to the mass effect of the tumor. It may also contribute to keeping the disease under control with targeted adjuvant therapies by clarifying the pathological diagnosis of the lesion. [ABSTRACT FROM AUTHOR]

Background: Surgical treatment of optic nerve tumors is challenging. The study's objective was to evaluate the efficacy of a combined endoscopic transethmoid and transconjunctival approach in patients without functional vision. Design: A retrospective, noncomparative case series. Methods: Retrospective data were collected from all patients who had undergone tumor resection using this approach at the authors' institution between 2015 and 2021. Preoperative assessments included magnetic resonance imaging and ophthalmological examinations, and re-assessments were conducted three months after surgery and regularly during the follow-up period. Results: Seventeen patients, mean age 35 ± 19.0 years, were enrolled. Of these, 64.7% presented with visual acuity (VA) of light perception or no light perception. Gross total resection was realized in all patients. The average decline in exophthalmos was 3.63 ± 1.93 mm. Tumor histopathological analysis identified 12 optic nerve sheath meningiomas and 5 optic gliomas. The mean follow-up time was 30 months during which there was no local recurrence in any of the patients. Conclusions: The combined endoscopic transethmoid and transconjunctival approach offers an additional choice for accessing optic nerve tumors. The procedure is both safe and effective and provides an alternative transcranial route to the orbit. [ABSTRACT FROM AUTHOR]

Resumen: Se presenta el caso de un glioma en ambos nervios ópticos en un paciente con antecedentes médicos de neurofibromatosis tipo 1. El paciente presentaba dolor retro-ocular bilateral constante, refractario a tratamiento analgésico y visión borrosa. En la exploración se apreciaban nódulos de Lisch en la superficie del iris y los nervios ópticos pálidos en el fondo de ojo. La resonancia magnética nuclear reveló una gran masa supraselar separada de la glándula pituitaria. Abstract: We present the case of glioma in both optic nerves in a patient with a medical history of neurofibromatosis type 1. The patient presented constant bilateral retro-ocular pain refractory to analgesic treatment and blurred vision. On examination, Lisch nodules were seen on the surface of the iris and pale optic nerves in the fundus. Nuclear magnetic resonance revealed a large suprasellar mass separate from the pituitary glands.

The sphenoid ridge approach (SRA) was initially described as a surgical technique for treating vascular pathologies near the Sylvian fissure. However, limited studies have systematically explored the use of skull base techniques in pediatric patients. This study investigated an extended variation in the sphenoid ridge approach (E-SRA), which systematically removed the pterion, orbital walls (roof and lateral wall), greater sphenoid wing, and anterior clinoid process to access the base of the skull. Objective: This report aimed to evaluate the advantages of the extradural removal of the orbital roof, pterion, sphenoid wing, and anterior clinoid process as a complement to the sphenoid ridge approach in pediatric patients. Patients and Methods: We enrolled 36 patients with suspected neoplastic diseases in different regions. The E-SRA was performed to treat the patients. Patients were included based on the a priori objective of a biopsy or a total gross resection. The surgical time required to complete the approach, associated bleeding, and any complications were documented. Results: Our results demonstrated that the proposed a priori surgical goal, biopsy, or resection were successfully achieved in all cases. In addition, using the E-SRA technique was associated with a shorter operative time, minimal bleeding, and a lower incidence of complications. The most frequently encountered complications were related to dural closure. Conclusions: The extended sphenoid ridge approach represents a safe and effective option for managing intracranial tumors in pediatrics.

BackgroundHemorrhage into optic pathway–hypothalamic glioma (OPHG) is rare. Variable clinical presentations and outcomes are associated with such pathology. We aim to present two infants presented with OPHG and a systematic review of the literature.MethodsWe describe two cases of infants presenting with sudden decreased vision, poor feeding, and irritability due to OPHG. Both patients underwent urgent craniotomy and subtotal resection followed by chemotherapy. We systematically reviewed the literature using PubMed, Google Scholar, and Embase. In addition, we included all English published reports for all ages discussing the optic pathway (optic nerve and optic chiasm) or hypothalamic glioma associated with hemorrhage from the year of the first reported case (1970) to January 2022.ResultsOf 17,949, 44 articles met the inclusion criteria of this review. A total of 56 cases were described with a mean of 21.35 years (0.5–70), with the male gender 52% and the female gender 45%. The hemorrhage location was sellar/suprasellar in 43% cases. Histopathology of included cases was pilocytic astrocytoma in 41%, followed by pilomyxoid astrocytoma in 16% cases. The outcome was unfavorable; 37.5% cases showed improvement, whereas 18% cases resulted in death.ConclusionApoplexy of the OPHG can be fatal and associated with poor outcomes. A systematic review of the literature has shown that younger age, pilocytic or pilomexyoid astrocytoma histopathology, and chiasmal/hypothalamic locations are associated with a higher risk of intertumoral hemorrhage and poor prognosis. Further genetic studies for OPHG may provide information for high-risk patients.

Marcella Nebbioso,1,* Antonietta Moramarco,1,* Alessandro Lambiase,1 Sandra Giustini,2 Marco Marenco,1 Emanuele Miraglia,2 Pasquale Fino,2 Chiara Iacovino,2 Ludovico Alisi1 1Department of Sense Organs, Sapienza University of Rome, Rome, Italy; 2Department of Dermatology, Sapienza University of Rome, Rome, Italy*These authors contributed equally to this workCorrespondence: Alessandro LambiaseDepartment of Sense Organs, Sapienza University of Rome, Viale del Policlinico 155, Rome 00161, ItalyTel +390649975357Fax +390649975425Email alessandro.lambiase@uniroma1.itIntroduction: Neurofibromatosis type 1 (NF1) is a multisystemic disease caused by the mutation of Nf1 gene located on chromosome 17q11.2. The mutation determines the loss of function of the protein neurofibromin with consequent uncontrolled cellular proliferation. Patients are characterized by a wide range of dermatological, neurological, and ophthalmological symptoms.Purpose: The aim of the study was to evaluate, through pattern visual evoked potentials (p-VEPs) and frequency doubling technology (FDT) Matrix perimetry, the objective and psychophysical functionality of the optic pathways in a group of NF1 patient.Methods: The study group consisted of 26 patients affected by NF1 and 17 healthy controls. Each patient underwent a complete ophthalmological examination, p-VEPs with the evaluation of amplitude and latency of the P100 wave, and FDT perimetry, with the evaluation of central sensitivity (CS), mean deviation (MD), pattern standard deviation (PSD) and glaucoma hemifield test (GHT).Results: NF1 patients showed a statistically significant alteration in the transmission of visual impulse. P-VEPs results highlighted a reduced amplitude and an increased latency of the P100 wave, suggesting an involvement of the visual pathway. Visual field analysis showed a significant reduction in all the observed parameters as well (CS, MD, PSD, and GHT).Conclusion: The present study showed, in NF1 patients, a qualitative and quantitative alteration in the conduction of stimuli through the visual pathways. The observed alterations are present, although, only at a subclinical level. None of the patients included in the study showed any manifest visual deficit nor had any concomitant pathology that might have affected the outcome of the study. In conclusion, electrophysiological exams and computer perimetry may take part, alongside a wider array of exams, in the differential diagnosis and later monitoring of NF1.Keywords: electrophysiologic testing, frequency doubling technology Matrix perimetry, FDT, neurofibromatosis type 1, optic glioma, pattern visual evoked potentials

Background: With the recognition that noncancerous cells function as critical regulators of brain tumor growth, we recently demonstrated that neurons drive low-grade glioma initiation and progression. Using mouse models of neurofibromatosis type 1 (NF1)-associated optic pathway glioma (OPG), we showed that Nf1 mutation induces neuronal hyperexcitability and midkine expression, which activates an immune axis to support tumor growth, such that high-dose lamotrigine treatment reduces Nf1-OPG proliferation. Herein, we execute a series of complementary experiments to address several key knowledge gaps relevant to future clinical translation., Methods: We leverage a collection of Nf1-mutant mice that spontaneously develop OPGs to alter both germline and retinal neuron-specific midkine expression. Nf1-mutant mice harboring several different NF1 patient-derived germline mutations were employed to evaluate neuronal excitability and midkine expression. Two distinct Nf1-OPG preclinical mouse models were used to assess lamotrigine effects on tumor progression and growth in vivo., Results: We establish that neuronal midkine is both necessary and sufficient for Nf1-OPG growth, demonstrating an obligate relationship between germline Nf1 mutation, neuronal excitability, midkine production, and Nf1-OPG proliferation. We show anti-epileptic drug (lamotrigine) specificity in suppressing neuronal midkine production. Relevant to clinical translation, lamotrigine prevents Nf1-OPG progression and suppresses the growth of existing tumors for months following drug cessation. Importantly, lamotrigine abrogates tumor growth in two Nf1-OPG strains using pediatric epilepsy clinical dosing., Conclusions: Together, these findings establish midkine and neuronal hyperexcitability as targetable drivers of Nf1-OPG growth and support the use of lamotrigine as a potential chemoprevention or chemotherapy agent for children with NF1-OPG., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Objective: Neurofibromatosis (NF) is the most common autosomal dominantly inherited neurocutaneous syndrome. The characteristic features of NF type 1 (NF-1) are café au lait spots, axillary and inguinal freckling, peripheral neurofibromas, optic pathway glioma, and Lisch nodules. The present study aimed to analyze the clinical features of children with NF-1. Materials and Methods: In this study, the children with NF-1 diagnosed and followed-up in our center between 2000 and 2020 were retrospectively evaluated. Demographic and clinical features of patients were defined. Results: The study group consisted of 52 patients. Of those, 25 were boys and 27 were girls. The children's median age at diagnosis was 5.9 years (1-15.8). Café au lait (CAL) spots and axillary/ inguinal freckling were observed in 50 and 24 patients, respectively. Neurofibroma was present in 22 cases. Ten of the cohort had optic gliomas, and 39 of them had cranial hamartomas. Orthopedic complications such as scoliosis, tibial pseudoarthrosis, and osteoporosis were observed in 13 patients. Eleven children had neurocognitive disorders. Conclusions: Early diagnosis is important in neurofibromatosis to prevent the complications of the disease. Also, neurological development and secondary malignancy follow-up should be done carefully in this group of patients. [ABSTRACT FROM AUTHOR]

Objective: To investigate the variant spectrum and genotype–phenotype correlations in a Turkish cohort with Neurofibromatosis Type‐1 (NF1). Materials and methods: We retrospectively investigated the clinical and molecular data of 138 NF1 patients from 129 families who had been followed‐up for a median of 3.9 (1.25–18.5) years. Results: NF1 sequencing revealed 73 different intragenic variants, 19 of which were novel. Seven large deletions were detected by multiplex ligation‐dependent probe amplification (MLPA) analyses. The total detection rate of pathogenic NF1 variants was found to be 87.1%. Comparing age groups, cutaneous neurofibromas, freckling, and Lisch nodules were more prevalent in patients older than 12 years (p >.05). Optic glioma detected in 17.3% of the patients and was significantly more common before the age of 6 (p >.001). Other solid tumors developed in 5% of the patients. There was no genotype–phenotype correlation between patients with truncating and nontruncating variants. However, six out of seven patients with large deletions had significant developmental delay, one patient with the c.2970_2972delAAT (p.Met992del) variant had only typical pigmentary features, and another patient with the c.4267A > G (p.Lys1423Glu) variant had CALMs, freckling, neurofibromas, and Noonan‐like phenotype. Conclusions: We described 19 novel variants and seven large deletions in NF1. Applying MLPA assay in NF1 is useful in expanding the molecular diagnosis. Although very limited genotype–phenotype correlation has been reported in NF1, the fact that specific phenotypic findings were observed in our patients with large deletions and two intragenic variants supports the studies published recently. [ABSTRACT FROM AUTHOR]

Optic nerve glioma (ONG) is a rare, typically slow-growing WHO I grade tumor that affects the visual pathways. ONG is most commonly seen in the pediatric population, in association with neurofibromatosis type 1 syndrome. However, sporadic adult cases may also occur and may clinically behave more aggressively, despite benign histopathology. Genetic characterization of these tumors, particularly in the adult population, is lacking. A 39-year-old female presented with 1 month of progressive left-sided visual loss secondary to a enhancing mass along the left optic nerve sheath. Initial empiric management with focal radiotherapy failed to prevent tumor progression, prompting open biopsy which revealed a WHO I pilocytic astrocytoma of the optic nerve. Whole-exome sequencing of the biopsy specimen revealed somatic mutations in NF1,FGFR1 and PTPN11 that may provide actionable targets for molecularly guided therapies. Genetic characterization of ONG is lacking but is needed to guide the management of these rare but complex tumors. The genomic alterations reported in this case contributes to understanding the pathophysiology of adult sporadic ONG and may help guide future clinical prognostication and development of targeted therapies. [ABSTRACT FROM AUTHOR]

Brain tumors are the leading cause of cancer-related death in children, where low-grade gliomas (LGGs) predominate. One common hereditary cause for LGGs involves neurofibromatosis-1 (NF1) gene mutation, as seen in individuals with the NF1 cancer predisposition syndrome. As such, children with NF1 are at increased risk of developing LGGs of the optic pathway, brainstem, cerebellum, and midline brain structures. Using genetically engineered mouse models, studies have revealed both cell-intrinsic (MEK signaling) and stromal dependencies that underlie their formation and growth. Importantly, these dependencies represent vulnerabilities against which targeted agents can be used for preclinical investigation prior to clinical translation., Competing Interests: The author has no relevant conflicts to disclose., (© The Author(s) 2024. Published by Oxford University Press, the Society for Neuro-Oncology and the European Association of Neuro-Oncology.)

Neurofibromatosis type 1 is an autosomal dominant disorder which is characterized by multiple café-au-lait spots in the body, intertriginous freckles, Lisch nodules, neurofibroma, optic glioma and bone dysplasia. One of the clinical characteristics of Neurofibromatosis type 1 is the risk of benign and malignant tumor development. Optic gliomas, a type of astrocytoma, are the most common central nervous system complication in children with Neurofibromatosis type 1 and are seen in 10-15% of cases. In this case report, a patient with an optic glioma and a mutation that was not previously identified in the NF1 gene is presented in the light of the literature. Identification of new mutations that cause Neurofibromatosis type 1 disease and reporting of clinical findings caused by the mutations will allow a large proportion of genotypephenotype correlation. Early diagnosis has a great importance in terms of followup of patients for malignancies that may develop in the future. [ABSTRACT FROM AUTHOR]

Neurofibromatosis type 1 is a relatively common genetic disease, with a prevalence ranging between 1/3000 and 1/6000 people worldwide. The disease affects multiple systems with cutaneous, neurologic, and orthopedic as major manifestations which lead to significant morbidity or mortality. Indeed, NF1 patients are at an increased risk of malignancy and have a life expectancy about 10-15 years shorter than the general population. The mainstay of management of NF1 is a patient-centered longitudinal care with age-specific monitoring of clinical manifestations, aiming at the early recognition and symptomatic treatment of complications as they occur. Protocole national de diagnostic et de soins (PNDS) are mandatory French clinical practice guidelines for rare diseases required by the French national plan for rare diseases. Their purpose is to provide health care professionals with guidance regarding the optimal diagnostic and therapeutic management of patients affected with a rare disease; and thus, harmonizing their management nationwide. PNDS are usually developed through a critical literature review and a multidisciplinary expert consensus. The purpose of this article is to present the French guidelines on NF1, making them even more available to the international medical community. We further dwelled on the emerging new evidence that might have therapeutic potential or a strong impact on NF1 management in the coming feature. Given the complexity of the disease, the management of children and adults with NF1 entails the full complement healthcare providers and communication among the various specialties. [ABSTRACT FROM AUTHOR]

Pediatric low-grade gliomas represent the most common childhood brain tumor class. While often curable, some tumors fail to respond and even successful treatments can have life-long side effects. Many clinical trials are underway for pediatric low-grade gliomas. However, these trials are expensive and challenging to organize due to the heterogeneity of patients and subtypes. Advances in sequencing technologies are helping to mitigate this by revealing the molecular landscapes of mutations in pediatric low-grade glioma. Functionalizing these mutations in the form of preclinical models is the next step in both understanding the disease mechanisms as well as for testing therapeutics. However, such models are often more difficult to generate due to their less proliferative nature, and the heterogeneity of tumor microenvironments, cell(s)-of-origin, and genetic alterations. In this review, we discuss the molecular and genetic alterations and the various preclinical models generated for the different types of pediatric low-grade gliomas. We examined the different preclinical models for pediatric low-grade gliomas, summarizing the scientific advances made to the field and therapeutic implications. We also discuss the advantages and limitations of the various models. This review highlights the importance of preclinical models for pediatric low-grade gliomas while noting the challenges and future directions of these models to improve therapeutic outcomes of pediatric low-grade gliomas., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Yvone and Breunig.)

Purpose: Children with sporadic optic pathway glioma (OPG) commonly experience a decline in visual acuity (VA). This study aimed to quantify long-term VA outcomes after definitive radiation therapy (RT). Methods: From 1997 to 2017, 41 patients underwent RT for OPG and had baseline VA testing. All patients underwent serial VA testing every 3–6 months during the first 5 years and annually thereafter. The cumulative incidence of VA decline or improvement (per eye) was estimated using death as a competing risk. Results: Mean follow-up was 5 years. Most tumors (93%) involved the postchiasmatic optic tracts and/or hypothalamus. Of the tumors tested for BRAF alterations (n = 15), 67% had a BRAF fusion. Median time to VA decline was 20 months in the eye with worse vision and 22 months in the better eye. For the worse eye, the 5-year cumulative incidences of VA decline and improvement were 17.9% [95% confidence interval (CI) 7–32.8%] and 13.5% (95% CI 4.7–26.7%), respectively. For the better eye, the 5-year cumulative incidences of VA decline and improvement were 11.5% (95% CI 3.5–30.7%) and 10.6% (95% CI 2.6–25.2%), respectively. Visual outcomes did not correlate with radiographic evidence of tumor progression. Conclusions: The 5-year cumulative incidence of VA decline was low. VA decline is most likely to occur within the first 2 years after RT and is not associated with radiographic progression of disease, highlighting the need for frequent ophthalmologic exams during this period. [ABSTRACT FROM AUTHOR]

Objective: Optic gliomas are histologically benign and well differentiated pilocytic astrocytomas. The histopathologic features of the tumor are important prognostic markers that affect survival rates in association with location, the age of the patient, and neurofibromatosis type-1. Chemotherapy is the most important choice in the treatment and the clinicians' goal is to stay as far away from radiotherapy as possible. The combination of vincristine and carboplatin, which is a safe and long-lasting safe treatment plan that sets the stage for radiotherapy and surgeon avoidance, is one of the first choice standard treatment approaches. However, in these treatments, refractory disease, imatinib mesylate, a multi-tyrosine kinase inhibitor with a low rate of systemic side effects can be added as an important option. It can be used safely in pediatric patients. Because of small number of studies reported in this area, we wanted to share our good results regarding the use of imatinib mesylate with clinicians. Material and Methods: A total of 16 patients with optic glioma who were diagnosed between 2007-2017 at our oncology clinic were included in the study. Results: When clinically and radiologically progressive disease was present after two cycles of the vincristine carboplatin combination, imatinib (270 mg/m2 oral) treatment was added for 1-2 years until stable disease or regression findings were observed. The median follow-up period of the patients was 7 (5-10) years. There was a complete response in four patients and stable disease findings in two patients. There was no imatinib-related side effect in our patients. Conclusion: Imatinib acts mainly by inhibiting the expression of PDGFR-a and P from tumor capillary endothelia. We believe that the inclusion of smart target molecules will reduce the need for radiotherapy, which is associated with late side effects in progressive disease. Many molecular targeting agents that may be implemented in the future may enter the treatment of refractory optic gliomas and children can be protected from complications arising from surgery and radiotherapy in this manner. [ABSTRACT FROM AUTHOR]

Highlights • Orbital tumors involving the optic nerve are challenging to treat. • To ensure non-tumor side visual function, optic nerve transection is necessary. • The lateral approach for this type of tumor is less invasive. Abstract Although orbital tumors involving the optic nerve are rare, it is well-known that they are very likely to cause serious visual impairment in a patient. Unfortunately, at present, there are no effective interventions that can reliably preserve visual function while controlling tumor growth into intracranial spaces. To ensure visual function of the non-affected side, transection of the optic nerve together with the tumors involved is necessary in some cases. For this procedure large craniotomy and orbital unroofing are commonly utilized. As an alternative, we propose a novel surgical intervention for transection of the optic nerve having optic nerve tumors, which utilizes a lateral orbitotomy approach. To evaluate the invasiveness of different surgical approaches, we compared the days of hospitalization after surgery across patients who underwent the transcranial, lateral, and anterior approaches, respectively. We successfully removed 2 optic nerve tumors using the lateral approach, which required significantly shorter hospitalization than the transcranial approach. The transection of the optic nerve together with tumor removal by the lateral approach may be one of the novel surgical interventions for optic nerve tumors as this method is considerably less invasive than the transcranial removal method. [ABSTRACT FROM AUTHOR]