Optic Glioma Research Articles

Multimodal Imaging of Choroidal Nodules in Neurofibromatosis Type I.

To clarify the possibilities and role of posterior segment imaging in patients with neurofibromatosis type I (NF1), and to show the prevalence of this disease in the pediatric population in Slovakia. Until recently, ophthalmologic consultations in patients with NF1 were limited mainly to the observation of Lisch nodules of the iris and the presence of optic nerve glioma. However, advances in imaging capabilities have made it possible to investigate and describe new f indings concerning the ocular manifestations of this disease. Between October 2020 and November 2021, we examined the anterior and posterior segment of 76 eyes (38 children – 12 boys and 26 girls) with genetically confirmed NF1 gene mutation at our clinic. The age of the patients ranged from 4 to 18 years. The anterior segment was checked for the presence of Lisch nodules biomicroscopically with a slit lamp. On the posterior segment, the presence of choroidal nodules was checked by various imaging methods – fundus camera, infrared confocal selective laser ophthalmoscopy, MultiColor imaging, OCT, and OCT angiography. All the patients had magnetic resonance imaging performed in order to detect potential optic nerve gliomas for the purpose of diagnosis. We observed the correlation between the patients’ age, presence of Lisch nodules and the presence of choroidal nodules. Eight patients also had other manifestations of the disease – optic nerve gliomas or microvascular changes (so-called “corkscrew” vessels). Out of 38 patients, Lisch iris nodules were present in 20 patients (53%) and choroidal nodules in 24 patients (63%). There was no positive correlation between the presence of these two manifestations within the same patient or eye, but there is a clear correlation between the presence of choroidal nodules and patient age. The results suggest that a previously unknown ocular manifestation of neurofibromatosis type I, namely choroidal nodules, has a higher prevalence than Lisch nodules also in the pediatric population and can be easily visualized using various imaging modalities. It will be important to include follow-up observation of this finding among the standard controls for ocular findings in NF1, and it will be very interesting to correlate this f inding with the exact NF1 mutation

Case report: A case report of optic nerve glioma in a 5-year-old African girl

Background: Optic nerve gliomas are rare tumors that constitute less than 5% of all pediatric central nervous system tumors.
 Case Presentation: We present the case of a 5-year-old girl with complaints of progressive protrusion of the right eye and poor vision of 3 years duration who was referred to the ophthalmologist. Ophthalmological evaluation of the right eye revealed tearing, no perception of light, inferior dystopia, severe proptosis, and a firm non-tender orbital mass palpable posterior to the eyeball. The cranial CT-scan was suggestive of a right optic nerve glioma. Histology showed Optic Glioma with extensive proliferation of meningothelial cells.
 Conclusion: Optic gliomas can be associated with extensive proliferation of meningothelial cells that can histologically mimic a meningioma. It is important to be cautious about making a diagnosis of meningioma for tumors in locations that are also characteristic of optic nerve gliomas especially in appropriate clinical settings. 
 
 
 French title: Rapport de cas : Un rapport de cas de gliome du nerf optique chez une fillette africaine de 5 ans Titre en cours - Gliome optique chez une fillette africaineContexte de l'étude : Les gliomes du nerf optique sont des tumeurs rares qui constituent moins de 5 % de toutes les tumeurs pédiatriques du système nerveux central.
 Présentation de cas : Nous présentons le cas d'une fillette de 5 ans présentant des plaintes de protrusion progressive de l'œil droit et une mauvaise vision depuis 3 ans qui a été référée à l'ophtalmologiste. L'évaluation ophtalmologique de l'œil droit a révélé un larmoiement, une absence de perception de la lumière, une dystopie inférieure, une exophtalmie sévère et une masse orbitaire ferme et non douloureuse, palpable en arrière du globe oculaire. Le scanner crânien était évocateur d'un gliome du nerf optique droit. L'histologie montrait un gliome optique avec une prolifération étendue de cellules méningothéliales.
 Conclusion : Les gliomes optiques peuvent être associés à une prolifération étendue de cellules méningothéliales pouvant mimer histologiquement un méningiome. Il est important d'être prudent avant de poser un diagnostic de méningiome pour des tumeurs situées dans des localisations également caractéristiques des gliomes du nerf optique, en particulier dans des contextes cliniques appropriés.

Brain injury drives optic glioma formation through neuron-glia signaling

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.

A sellar-suprasellar malignant optic pathway glioblastoma in the absence of prior radiation therapy: illustrative case.

To date, only a few cases of sellar and suprasellar glioblastomas have been reported even though high-grade glioma constitutes the most common adult brain tumor, commonly arising in the cerebral hemispheres. It arises de novo from astrocytes within the optic nerve, optic chiasm, or optic tracts and is quite challenging to diagnose and treat. To the authors' knowledge, there are 72 cases (including this one) of optic glioma malignancies in the medical literature, 30 corresponding to glioblastomas. The authors present the diagnostic considerations and challenges, management strategies, and clinical course of a very large sellar-suprasellar glioblastoma in a 19-year-female who had never received radiation therapy or prior surgery. Sellar-suprasellar glioblastomas, although extremely rare, are known to occur and pose challenges in their diagnosis and preoperative treatment planning. The presence of diffusion restriction on diffusion-weighted magnetic resonance imaging in a mass lesion that has ring and nodular postcontrast enhancement in addition to absent calcification on computed tomography should be alert to the possibility of a high-grade mass. This is extremely important for preoperative patient counseling and planning for the multimodal treatments, because sellar-suprasellar glioblastomas carry a poorer prognosis than the common benign mass lesions in the region.

Orbital tumors

Orbital tumours include a variety of orbital diseases of different origins. In the case of malignant orbital tumours, early detection is important so that treatment can be initiated promptly. Neuroradiological imaging, in particular magnetic resonance imaging (MRI), plays an important role in the diagnostic of orbital tumours. In adults, lymphoproliferative diseases, inflammations and secondary orbital tumours are most frequently found, whereas in children mostly dermoid cysts, optic gliomas and capillary haemangiomas are found. Optic glioma is a pilocytic astrocytoma and accounts for two thirds of all primary optic tumours. Optic nerve sheath meningiomas mostly affect middle-aged women. In childhood, retinoblastoma is the most common intraocular tumour. This is an aggressive malignant tumour which can occur unilaterally or bilaterally. Based on the imaging findings, differential diagnoses can usually be easily narrowed down using criteria such as age of manifestation, frequency, localisation and imaging characteristics.

Orbital Neurogenic Tumors: An Eye Care Service Experience in Turkey

Introduction:This study aimed to evaluate the clinical and pathological features and treatment outcomes of neurogenic tumors developing in the orbit.
 Materials and Methods: A retrospective study was conducted on the medical records of 23 patients diagnosed with orbital neurogenic tumors between 2008 and 2020 in the ophthalmology clinic. Clinicopathologic features and treatment results of this patient group were evaluated.
 Results: Twenty-three patients, mean (SD) age 33.34±20.18 (min-max 4-60) years, were included in this study. Median follow-up time was 56.7±42.7 (min-max 9-120) months. At the time of presentation, 15 (65%) patients had proptosis, 8 (35%) patients had strabismus and reduced vision. Histopathologic diagnosis was made after lateral orbitotomy through the skin in 16 patients (69.5%) and medial orbitotomy through the conjunctiva in 4 patients (17.4%). The diagnosis was established clinically in three (13%) cases. Ten patients (43.4%) underwent whole excisional biopsy, nine patients (391.1%) underwent incisional biopsy, and one patient (4.3%) underwent subtotal excisional biopsy. Nine (39.1%) of the orbital neurogenic tumors were diagnosed as meningiomas based on histological and clinical findings, eight (34.8%) as optic nerve gliomas, and the other six (26%) as peripheral nerve origin tumors. Four (44.5%) of the meningiomas originated from the sphenoid wing, and five (55.5%) from the optic nerve sheath. As a treatment modality, external radiotherapy was administered to fifteen patients (65.2%), cyberknife radiosurgery to one patient (4.3%), chemotherapy to one patient (4.3%), and exenteration surgery to one patient (4.3%).
 Discussion: According to our study, meningioma, optic nerve glioma, and peripheral nerve sheath tumors were the most frequent neurogenic tumors of the orbit. Gliomas and meningiomas of the optic nerve sheath were treated with external radiation. Total excision was performed for schwannoma and solitary neurofibroma among the peripheral nerve sheath tumors, while subtotal excision was performed for infiltrative plexiform neurofibroma. With the treatments applied, survival and the visual prognosis were satisfactory.

10006-PEDT-1 PEDIATRIC LOWER GRADE GLIOMA SURGERY IN THE ERA OF GENOMIC MEDICINE

Abstract INTRODUCTION In the new WHO Brain Tumor Classification of 2021, pediatric-type gliomas are classified separately from adult-type tumors. Additionally, with the advancement of cancer genomics, treatment options have expanded. Here we consider surgery for pediatric low-grade gliomas. METHODS We retrospectively analyzed 41 cases of low-grade gliomas or glioneuronal tumors in patients under 18 years of age who underwent surgery at our institute from 2002 to March 2023. We discussed surgical strategies based on molecular classification. RESULTS Among the cases, there were 34 gliomas and 7 glioneuronal tumors. According to the new WHO classification, they corresponded to 1) Adult-type diffuse gliomas, 2) Pediatric-type diffuse low-grade gliomas, 3) Circumscribed astrocytic tumors, or 4) Glioneuronal and neuronal tumors. Cases without molecular diagnosis were also considered in light of the new WHO classification. DISCUSSION Among molecularly diagnosed astrocytomas involving the cerebral hemisphere, brain stem, spinal cord, there were no cases of 1), and 2) 3) were the main cases. It is important in surgical selection to note that these cases generally have a more favorable prognosis compared to the adult type and have usefulness in diagnosing MAPK pathway abnormalities leading to the selection of molecularly targeted drugs. 3) includes pilocytic astrocytoma, subependymal giant cell astrocytoma, and pleomorphic xanthoastrocytoma. Among these, in the treatment of pilocytic astrocytomas located in the optic pathway and hypothalamus, biopsy becomes necessary for molecular diagnosis and the selection of appropriate therapeutic agents. Conversely, for unilateral optic nerve gliomas, options other than resection may be considered. 4) is primarily associated with epilepsy-related tumors. Surgical resection holds the promise of controlling epilepsy in these cases. However, various genetic abnormalities have been identified, which could prove useful in diagnosis and treatment. CONCLUSION Based on the new WHO classification, a reevaluation of treatment strategies for pediatric brain tumors is necessary.

Optic nerve glioma in infants: About a case

Optic nerve glioma in infants: About a case

Clinically Aggressive Low-Grade Optic Nerve Glioma in an Adult Treated With Selumetinib.

Clinically Aggressive Low-Grade Optic Nerve Glioma in an Adult Treated With Selumetinib.

Presumed Malignant Optic Glioma of Adulthood: Prolonged Survival with Temozolomide and Radiotherapy.

Presumed Malignant Optic Glioma of Adulthood: Prolonged Survival with Temozolomide and Radiotherapy.

Screening saves sight: An unusual case of type-1 neurofibromatosis

Neurofibromatosis (NF), described by von Recklinghausen in 1882, consists of at least two distinct disorders: NF1 (von Recklinghausen's or peripheral neurofibromatosis) and NF2, formerly known as 'central neurofibromatosis." The prevalence of NF is approximately 1 in 4,000, and of NF2, 1 in 50,000. Neurofibromatosis type 1 is a multisystemic neurocutaneous disorder with an autosomal dominant hereditary pattern. Ocular manifestations include plexiform neurofibroma of eyelid, Lisch nodules in iris, optic nerve glioma, glaucoma, sphenoid wing dysplasia. Retinal and choroidal involvement are encountered less frequently. Unusual ocular findings include multiple choroidal nevi, combined hamartoma, choroidal Schwannoma, choroidal melanoma and vaso proliferative retinal tumors.Here we report a case of an 18 year old girl diagnosed with neurofibromatosis type 1 who on routine ocular examination was found to have high myopia in both eyes and on fundus examination had a macula ‘on’ inferior retinal detachment with retinal hole in right eye. Inferior retinal detachment is rarely reported in neurofibromatosis type 1. This case emphasizes the importance of conducting ocular examination even in asymptomatic patients with neurofibromatosis, so that early detection and treatment can prevent vision loss secondary to retinal detachment.

CNSC-43. TARGETING NEURONAL EXCITABILITY FOR NF1 LOW-GRADE GLIOMA THERAPY

Abstract While neuronal activity has previously been implicated in malignant glioma growth control, we recently demonstrated that neuron excitability can also regulate low-grade (optic) glioma initiation and progression. In this prior study, we showed that NF1 germline mutation-dependent neuronal excitability sustains optic glioma growth through HCN channel-mediated midkine activation of a T cell-microglia stromal circuit. Relevant to clinical translation, lamotrigine modulation of HCN channel function reduced neuronal hyperexcitability, midkine production and optic glioma (OPG) growth. To establish an obligate role for neuronal activity and midkine (Mdk) production in OPG growth, we leveraged a series of unique genetically engineered mouse models. First, we demonstrate that midkine is necessary for gliomagenesis, as Nf1-OPG; Mdk-/- mice do not develop tumors and have restored retinal pathology, as evidenced by increased retinal ganglion cell (RGC) numbers and retinal nerve fiber layer thickness. Second, we show that midkine production and neuronal hyperactivity are interdependent, such that only tumor-associated germline Nf1 mutations result in increased RGC excitability and midkine production, whereas those mutations that do not cause optic gliomas lack RGC hyperexcitability or elevated midkine expression. Third, lamotrigine treatment both during and after Nf1-OPG development attenuates midkine levels and tumor proliferation. Moreover, this anti-tumoral effect is durable for months after the cessation of treatment. Fourth, oral treatment of Nf1-OPG-bearing mice with clinically relevant doses of lamotrigine (2.5-7.5mg/kg/day) during OPG development blocks tumor formation. Together, these data establish midkine and neuronal hyperexcitability as key drivers of Nf1 optic glioma growth, relevant to planned clinical trials of this anti-seizure medication for children with NF1-OPG.

TMIC-13. EXHAUSTED CD8+ T CELLS MAINTAIN LOW-GRADE GLIOMAS IN NF1-MUTANT MICE

Abstract T cells are minor cellular constituents of the brain tumor microenvironment, but have recently been shown to play critical roles in glioma pathobiology and treatment. Previous studies from our laboratory have shown that T cells are required for the formation and growth of low-grade gliomas (LGGs) in murine models of the Neurofibromatosis type 1 (NF1) tumor predisposition syndrome. To better characterize the immune landscape of these pediatric low-grade tumors, we leveraged single cell RNA sequencing of human pediatric pilocytic astrocytomas and genetically engineered mouse LGG (Nf1-optic glioma) models. First, we showed that both human and murine LGGs contain a CD8+ T cell population expressing PD-1 and TIGIT, similar to conventional exhausted T cell populations. Second, these PD-1+/TIGIT+ CD8+ T cells are actively recruited to the tumor site by Ccl2 where they dictate tumorigenesis through the elaboration of Ccl4, a cytokine necessary for microglia Ccl5-mediated support of Nf1-OPG growth. As such, Ccl4 expression was enriched in PD-1+/TIGIT+ CD8+ T cells relative to all other T cell populations within these tumors. Third, this “exhausted” CD8+ T cell population was exclusively present in the optic nerves, but not in the blood, dura, or deep cervical nodes of optic glioma-bearing mice. Fourth, targeting this PD1+/TIGIT+ exhausted CD8+ T cell population with immune checkpoint monoclonal antibody inhibitors reduced CD8+ T cell tumoral recruitment, Ccl4 production, and optic glioma growth. Collectively, these findings establish an obligate role for PD-1+/TIGIT+ CD8+ T cells in Nf1-optic glioma control and suggest that immune checkpoint modulation may be useful for the treatment of LGGs in children.

MODL-07. NF1 MUTATION IN OLIGODENDROCYTE PRECURSOR CELLS INDUCES PRENEOPLASTIC LESIONS IN THE BRAIN

Abstract Oligodendrocyte precursor cells (OPCs) are progenitor cells that give rise to oligodendrocytes in the central nervous system throughout the lifespan. Transcriptomic and lineage tracing studies suggest that OPCs may be the putative cell of origin for many gliomas in children and adults. While children with the neurofibromatosis type 1 (NF1) cancer predisposition syndrome typically develop optic pathway and brainstem gliomas, as many as 50% of children develop gliomas in other brain regions using radiologic criteria. Relevant to these gliomas, discrete patches of hyperdense OPCs were found in the brains of Nf1+/- mice. The OPCs within the lesions display a transient increase in proliferation and hypercellularity. When the brains of mice carrying different heterozygous NF1 patient derived germline Nf1 gene mutations were examined, hyperdense OPC lesions were only seen in mice whose Nf1 mutations also predispose to optic gliomas. Mechanistically, monoallelic KRAS hyperactivation also results in similar OPC hyperdense lesions. Moreover, OPC-specific Nf1-heterozygous mice display similar lesions, while OPC-specific Nf1-knockout results in generalized OPC hyperdensity throughout the entire brain. Taken together, these data suggest the existence of a preneoplastic state conferred by Nf1 mutation in OPCs and establish a tractable model system to explore the transition to glioma in children with NF1.

Prechiasmatic Transection of the Unilateral Dodge Class Ⅰ Optic Pathway Glioma without Neurofibromatosis Type 1: Technical Description and Clinical Prognosis

For unilateral Dodge Class Ⅰ optic pathway glioma (OPG-uDCⅠ) without neurofibromatosis type 1, unilateral isolated optic nerve gliomas before the optic chiasm have been confirmed to possibly cause visual deterioration and poor prognosis. For this type of highly selective localized tumor, we explored surgery as the only treatment method. This article retrospectively analyzed and summarized the clinical data of this case series, with the aim of exploring the main technical details and clinical prognosis. Included were patients with OPG-uDCⅠ without neurofibromatosis type 1 and experiencing vision loss on the affected side. The fronto-orbital approach was used, which was mainly divided into 3 parts: intraorbital, optic canal, and intracranial. All patients underwent prechiasmatic resection without any adjuvant treatments. The follow-up period was 3months after surgery, and magnetic resonance imaging and contralateral visual acuity were reviewed annually after surgery. All OPG-uDCⅠ cases were completely removed without any adjuvant treatments, and there was no recurrence during the follow-up period. Pathological results showed that, except for 1 adult patient with pilomyxoid astrocytoma (World Health Organization grade Ⅱ), the others all had pilocytic astrocytoma (World Health Organization grade Ⅰ). Five patients experienced transient ptosis, and all recovered 3months after surgery. For OPG-uDCⅠ without neurofibromatosis type 1, radical prechiasmatic resection of the tumor is possible, without the need for postoperative radiotherapy and chemotherapy.

Optic Pathway Gliomas in Pediatric Population-Current Approach in Diagnosis and Management: Literature Review.

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. 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. Further research into novel techniques for detecting gliomas would allow for early monitoring of the disease.

Primary Tumours of The Optic Disc and The Optic Disc Sheath

Primary optic nerve and optic nerve sheath tumors constitute approximately 8% of intraorbital tumors and although most of them are benign, they are manifested by findings that significantly affect visual function such as vision loss, visual field defect and proptosis. Tumors originating from the optic nerve trunk are mostly benign optic nerve glioma, but rarer tumors such as ganglioglioma, medulloepithelioma, hemangioblastoma, melanocytoma and high-grade glioblastomas such as malignant optic nerve glioma can also be detected. Tumors originating from the optic nerve sheath usually have optic nerve sheath meningioma (ONSM), of those with intraorbital and intracanalicular origin are classified as primary and intracranial ONSMs are classified as secondary tumors. Optic glioma, ONSM, and hemangioblastomas can be seen sporadically or as a component of Type 1 and Type 2 Neurofibromatosis (NF) and Von Hippel-Lindau (VHL) syndromes, respectively. Treatment with systemic chemotherapy, surgical resection and radiotherapy methods should be considered when progressive vision loss, visual field defect and cosmetically intolerable proptosis develop in optic nerve and nerve sheath tumors, which can have a quiet course for years in terms of visual function. While systemic chemotherapy is accepted as the main treatment method in optic gliomas, more successful results are obtained with specialized treatment methods such as stereotactic fractionated radiotherapy in ONSMs.

SAT613 A Novel NF1 Mutation As The Underlying Cause Of Dysmorphic Features And Acromegaly In An Atypical Case Of Neurofibromatosis Type 1

Abstract Disclosure: O. Alsagheir: None. L.A. Alobaid: None. M. Alswailem: None. H. Al-Hindi: None. A.S. Alzahrani: None. Introduction: Neurofibromatosis type 1 is an autosomal dominant disease with an estimated incidence of about 1:2000 cases. It is caused by genetic alterations in the gene NF1 encoding the tumor suppressor gene, neurofibromin. Patients with neurofibromatosis 1 are at an increased risk of a number of benign and malignant tumors including optic nerve gliomas, CNS tumors, malignant peripheral nerve sheath tumors, pheochromocytomas and many others. However, pituitary adenomas have been rarely described in neurofibromatosis type 1 and NF1 mutations have been found rarely in patients without manifestations of neurofibromatosis. In this report, we describe a patient with acromegaly who had some dysmorphic features but no clear skin or other manifestations of neurofibromatosis. He was found to have a deletion mutation in NF1 suggesting that his dysmorphic features and acromegaly are atypical manifestations of a previously undiagnosed neurofibromatosis type 1. Case Description: A 26-year-old-man presented at 18 years of age for evaluation of possible ventricular septal defect, which was ruled out by echocardiography, but he was found to have a subaortic membrane with moderate aortic regurgitation. He was also noticed to have coarse facial and body features which raised the possibility of acromegaly. He didn’t notice any facial changes, change in the size of hands and feet, headache or visual disturbances. In the family history, he reported that a number of his siblings are tall with large body habitus; none of them was evaluated or known to have medical illness. Physical examination: height 184 cm, weight 87 Kg, BMI 25, and BP 117/77 mmHg. He has frontal bossing, large supraorbital ridges, macrognathia, and hoarse deep voice but no skin tags, café au let spots, skin fibromas or freckling. Eye examination was unremarkable. Investigations: IGF-1 415 ng/ml (188-400), random GH 1.09 ng.ml (0.1-1.2). An oral glucose tolerance test showed baseline GH 0.99 increased to 8.05 ng/ml. An MRI of the pituitary gland showed a lobulated sellar and suprasellar heterogeneously enhancing pituitary adenoma. A Gallium 68 PET-CT scan showed an intense focus of uptake at the same location. Whole exome sequencing revealed a heterozygous NF1 mutation (NM_001128147.3: c.1782_*2del). This variant is likely pathogenic according to ACMG criteria. Conclusion: This case illustrates the value of whole exome sequencing for genetic testing in diagnosing atypical dysmorphia and other conditions when the diagnosis is not clear on clinical evaluation or conventional investigations. It also describes a rare association of acromegaly with neurofibromatosis. Presentation: Saturday, June 17, 2023

Regos nervo glioma

Optic nerve glioma (ONG) is usually a low-grade tumor of the optic nerve. ONG can affect not only the optic nerve, but also the optic nerve chiasma and optic nerve tract. ONG can be classified as associated with neurofibromatosis type 1 (NF1) or sporadic ONG. Sporadic gliomas are more commonly diagnosed in adults, have an aggressive course, and are known to have a poor outcome. The disease can be asymptomatic. ONG often causes visual disturbances such as reduced visual acuity, visual field defects, and impaired color vision; due to the tumor mass effect, proptosis, strabismus, and diplopia are possible. As the disease progresses, various neurological symptoms can appear, including headache, hemiplegia, and endocrine disorders such as early maturation, growth hormone hypersecretion, or deficiency. A presumed diagnosis is based on clinical presentation and neuroimaging findings. Meanwhile, biopsy should be avoided due to the high probability of optic nerve damage. Treatment is individual for each patient, but remains controversial to this day. Thus, in this article, we review the prevalence, clinic, diagnostic and treatment options of ONG.

Evaluation of Neurofibromatosis Type 1 Associated Optic Pathway Gliomas

Background/Aims: Optic pathway gliomas (OPGs) are low-grade gliomas histologically represented by pilocytic astrocytoma (PA) in 90% of cases, can develop from any part of the visual pathways such as optic nerve, chiasm, optic tract, or optic radiations which frequently involve the hypothalamus. OPGs account for 3–5% of childhood central nervous system (CNS) tumors and about 2% of pediatric glial lesions. OPGs are believed to be the most prevalent intracranial tumor in patients with neurofibromatosis type 1 (NF-1) and can occur in 15–20% of NF-1 cases. The aim of this study is to evaluate the clinical features and treatment response in patients diagnosed with optic glioma and NF-1.
 Methods: All cases diagnosed with OPG and received treatment in the Pediatric Oncology Department, between January 2015 to January 2021 were retrospectively evaluated. Inclusion criteria include children and adolescents with OPG aged between 0 and 18 years. The medical records (gender, age, tumor entity, tumor location) of patients, as well as their treatment history and magnetic resonance imaging (MRI) scans, were examined. The diagnosis of OPG was made clinically and radiologically by the tumor board. The recommendations of the Response Assessment in Pediatric Neuro-Oncology (RAPNO) working group were used in the diagnosis and evaluation of treatment response. Patients received intravenous chemotherapy with SIOP LGG 2004 (vincristine- carboplatin) with or without bevacizumab (10 mg/kg, started every 2 weeks), therapy or vinblastine (3 mg/m2, weekly). 
 Results: This study included 27 cases during the study period from January 2015 to January 2021. In this study there were 14 male (51.8 %) and 13 female (48.1 %) patients. The median age was 4.8 (range: 0.5–14.9) years. Biopsy was performed in three patients and the diagnosis was low-grade glioma (pilocytic astrocytoma) for all of them. Chemotherapy was administered to 22 cases in total. Twelve patients received vincristine-carboplatine, 5 patients received vincristine-carboplatin with bevacizumab and 5 patients received vinorelbine. Radiological response was evaluated in all 22 patients at 3 months MRI. No patient had a radiological complete respons, 11 patients (50%) had partial response, 2 patients (9%) presented with a progressive disease, showing an increase in measurements of 35% and 9 patients(40.9%) had stable disease at the 3-month evaluation.
 Conclusions: Systemic and visual problems play a significant role in the selection of treatment for pediatric patients with optic gliomas. An essential treatment option for improving symptoms and reducing tumor size is systemic chemotherapy. A crucial therapy option for enhancing vision is bevacizumab for the patients with NF-associated OPG.