Neurofibromatosis type 1 and optic pathway gliomas Follow-up of 54 patients

Neurofibromatosis Type 1-Associated Optic Pathway Gliomas: Current Challenges and Future Prospects

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.

The role of visual electrodiagnostics in management of children with neurofibromatosis type 1

PURPOSE

To evaluate the role of visual electrodiagnostic testing in children with neurofibromatosis type 1 (NF1) despite improved accessibility to magnetic resonance imaging (MRI).

METHODS

The records from 39 children (78 eyes, 15 boys, 24 girls, average age at last visit of 11.5 ± 4.3 years, average follow-up time of 7.8 ± 3.9 years) with genetically confirmed NF1 were retrospectively analysed. They all underwent a thorough ophthalmological investigation, including age-appropriate visual acuity testing, anterior segment evaluation for Lisch nodules and a dilated fundus examination. If children were cooperative enough, colour vision was tested using the Hardy-Rand-Rittler test, visual fields were evaluated with Goldmann perimetry. All performed MRI of the brain and orbits as part of the standard of care protocol. Visual electrodiagnostics included electroretinography (ERG) and visual evoked potentials (VEP) using a standard protocol in older children, whereas with less cooperative children a modified protocol according to the Great Ormond Street Hospital (GOSH protocol) was used.

RESULTS

The average visual acuity was 0.8 ± 0.3, colour vision was abnormal in 6%, perimetry in 8%, Lisch nodules were present in 62%, and the optic disc was pale in 66% of all eyes. Plexiform neurofibroma of the eyelid/orbit was present in 4%. Optic pathway glioma (OPG) was detected with MRI in 22 (57%) and in 6/22 treatment was indicated. Other intracranial NF1-related lesions were documented in 70% of children. VEP were abnormal in 16/39 of all children with NF1 (41%) comprising 14/22 (65%) of children with confirmed OPG and 2/17 (12%) of children without OPG. All full-field and pattern ERG responses were within normal limits. All individual VEP results are described and three cases from this cohort of children are presented in detail to illustrate the importance of VEP testing. In Case 1, VEP abnormality suggested subsequent MRI of the brain under general anaesthesia, which was otherwise contraindicated according to normal clinical findings and his young age. In Cases 2 and 3, VEP provided more precise functional information during the follow-up of OPG, while other psychophysical tests remained unchanged.

CONCLUSIONS

Electrodiagnostics has multifactorial role and importance in children with NF1, either when visual pathway function is impaired in young children, even before MRI under general anaesthesia and other psychophysical tests can be performed, as well as for a more precise monitoring of the visual pathway function before potential treatment of OPG, or after it, to evaluate its success.

Optic Pathway Gliomas: The Trends of Basic Research to Reduce the Impact of the Disease on Visual Function

Pediatric optic pathway gliomas (OPG) are low-grade brain tumors characterized by slow progression and invalidating visual loss. Common therapeutic strategies include surgery, radiotherapy, chemotherapy, and combinations of these modalities, but despite the different treatment strategies, no actual treatment exists to prevent or revert visual impairment. Nowadays, several reports of the literature show promising results regarding NGF eye drop instillation and improvement of visual outcome. Such results seem to be related with the NGF-linked prevention in caspase activation, which reduces retinal ganglion cell loss.Reducing retinal ganglion cell loss results clinically in visual field improvement as well as visual electric potential and optical coherence tomography gain. Nonetheless, visual acuity fails to show significant changes.Visual impairment represents nowadays one of the major issues in dealing with OPGs. Secondary to the interesting results offered by NGF eye drop administration, further studies are warranted to better comprehend potential treatment strategies.

Cost Analysis of Orthoptist-Led Neurofibromatosis Type 1 Screening Clinics

Purpose

To conduct a costing study comparing orthoptist-led with consultant-led clinics screening for optic pathway gliomas (OPGs) in children with neurofibromatosis Type 1 (NF1) attending the Royal Children's Hospital (RCH), Melbourne.

Methods

Patients with NF1 examined in the orthoptist-led NF1 screening clinic and/or consultant-led clinics during the study period were identified. The workflow management software Q-Flow 6® provided data documenting patient's time spent with the orthoptist, nurse, and ophthalmologist. Time points were converted into minutes and multiplied by the cost-per-minute for each profession. A bottom-up micro-costing approach was used to estimate appointment level costs. Bootstrap simulations with 1000 replications were used to estimate 95% confidence intervals (CIs) for the difference in mean appointment time and cost between clinics.

Results

Data for 130 consultant-led clinic appointments and 234 orthoptist-led clinic appointments were extracted for analysis. The mean time per appointment for the consultant-led clinic was 45.11 minutes, and the mean time per appointment for the orthoptist-led clinic was 25.85 minutes. The mean cost per appointment for the consultant-led clinic was A $84.15 (GBP £39.60) compared to the orthoptist-led clinic at A $20.40 (GBP £9.60). This represents a mean reduction of 19.25 minutes per appointment (95% CI, -24.85 to -13.66) and a mean reduction of A $63.75 (GBP £30.00) per appointment (95% CI, (A $-75.40 to $-52.10 [GBP £ -35.48 to £ -24.52]).

Conclusion

An orthoptist-led clinic screening for OPGs in patients with NF1 can be a more cost-efficient model of care for ophthalmic screening in this patient group.

Optic pathway glioma and endocrine disorders in patients with and without NF1

BACKGROUND

Optic pathway gliomas (OPGs) are classified by anatomic location and the association with neurofibromatosis type 1 (NF1). Children with OPGs face sequelae related to tumor location and treatment modalities. We assessed the prevalence of endocrine dysfunction in children with OPGs and compared outcomes between those with and without NF1.

METHODS

We performed a retrospective medical record review of medical history, and clinical and laboratory data, of children diagnosed with OPGs (n = 59, 61% with NF1) during 1990-2020, followed at a tertiary endocrine clinic. Growth and puberty parameters and occurrence of endocrine dysfunction were evaluated.

RESULTS

Isolated optic nerve involvement was higher among patients with than without NF1. Patients without NF1 were younger at OPG diagnosis and more often treated with debulking surgery or chemotherapy. At the last endocrine evaluation, patients without NF1 had comparable height SDS, higher BMI SDS, and a higher rate of endocrine complications (78.3% vs. 41.7%, p = 0.006). Younger age at diagnosis, older age at last evaluation, and certain OPG locations were associated with increased endocrine disorder incidence.

CONCLUSIONS

Endocrine dysfunction was more common in patients without NF1; this may be related to younger age at presentation, tumor locations, a greater progressive rate, and more aggressive treatments.

IMPACT

The literature is sparse regarding sporadic OPGs, and the mean duration of follow-up is shorter than at our study. Our data show a higher rate of endocrine dysfunction in patients with OPGs than previously described. We also found a higher prevalence of endocrine dysfunctions among patients without compared to those with NF-1. A better understanding of the true prevalence of endocrine disabilities that may evolve along time can help in guiding physicians in the surveillance needed in patients with OPG.

Management of Optic Pathway Glioma: A Systematic Review and Meta-Analysis

Background: OPG accounts for 3−5% of childhood central nervous system (CNS) tumors and about 2% of pediatric glial lesions. Methods: Article selection was performed by searching PubMed, Web of Science, and Cochrane databases. Results: The pooled mortality rate was 0.12 (95%CI 0.09−0.14). Due to the unrepresentative data, improved and not changed outcomes were classified as favorable outcomes and worsened as unfavorable. Meta-analyses were performed to determine the rate of clinical and radiological favorable outcomes. In terms of visual assessment, the pooled rate of a favorable outcome in chemotherapy, radiotherapy, and surgery was 0.74, 0.81, and 0.65, respectively, and the overall pooled rate of the favorable outcome was 0.75 (95%CI 0.70−0.80). In terms of radiological assessment, the rate of a favorable outcome following chemotherapy, radiotherapy, and surgery was 0.71, 0.74, and 0.67, respectively, and the overall pooled rate of the favorable outcome is 0.71 (95%CI 0.65−0.77). The subgroup analysis revealed no significant difference in the rate of clinical and radiological favorable outcomes between the different treatment modalities (p > 0.05). Conclusion: Our analyses showed that each therapeutic modality represents viable treatment options to achieve remission for these patients.

Orbital Tumors-Clinical, Radiologic and Histopathologic Correlation

Orbital masses include a broad spectrum of benign and malignant entities. Often these masses are asymptomatic or show a slow growth rate, so that emergence of clinical symptoms is prolonged. In this context, cross-sectional imaging plays an elementary role in the characterization of these lesions. Aside from the characterization of the underlying entity, an evaluation of the involved compartments is possible by sufficient imaging, which also facilitates optimal treatment and surgery planning. The purpose of this review is to explore different benign and malignant orbital tumors and their typical appearance in imaging together with histopathologic findings.

Current update on the visual outcome of optic pathway glioma associated with neurofibromatosis type-1

Purpose

Clinical and diagnostic evaluation in the follow-up of optic glioma patients with neurofibromatosis type 1 (NF-1) can be difficult. Determining whether and when to provide treatment is a significant challenge in best managing these patients. Update on current information and future directions in management is included in this review.

Current Practice

NF-associated optic pathway gliomas (OPGs) present a significant management challenge with high stakes for visual outcomes. Monitoring vision and diagnostic tests are challenging in patients of a younger age. Regardless of whether few or many optic gliomas are encountered during clinical practice.

Summary

This review of optic gliomas-NF1-associated gliomas includes the current approach and knowledge of OPG-NF1 and future directions in OPG-NF1 management. This includes the ongoing Multicenter Natural History Study and other clinical trials and outcomes in NF-1 patients with OPG.

Visual Outcomes of Optic Pathway Glioma Treated With Chemotherapy in Neurofibromatosis Type 1

PURPOSE

To analyze the visual outcomes following chemotherapy for optic pathway glioma in children with neurofibromatosis type 1.

METHODS

This was a retrospective cohort study of 58 children with optic pathway glioma between 2003 and 2019. Best corrected visual acuity (BCVA) at diagnosis and at the last follow-up visit were analyzed. Correlation tests were performed to determine whether the final BCVA was predicted by the initial BCVA, initial Dodge stage, or retinal nerve fiber layer (RNFL) thickness stability. The first-line chemotherapy regimen included vincristine plus carboplatin (2003 to 2016) and vinblastine (since 2017).

RESULTS

Twenty-four children (41%) received chemotherapy. The median age at diagnosis was 3 years, and 61% of the children were female. From the first visit to the last follow-up visit, there was a statistically significant difference in mean BCVA in eyes in the no treatment group (P = .034) but not in eyes in the chemotherapy group (P = .824). A moderate and weak positive correlation was found (r = 0.58 and r = 0.29, respectively). At the last follow-up visit, BCVA remained stable in 73% and improved in 27% of eyes in the no treatment group, and BCVA worsened in 25%, remained stable in 62%, and improved in 13% of eyes in the chemotherapy group. At the last follow-up visit, BCVA and Dodge stage had a weak negative correlation (r = -0.06 and r = -0.17, respectively). A negative moderate correlation was identified between RNFL thickness and BCVA at the last follow-up visit (r = -0.48 in the no treatment group and r = -0.46 in the chemotherapy group).

CONCLUSIONS

Children treated with chemotherapy had worse BCVA, although the treatment arrested the decline or improved BCVA in 75% of the patients with no major side effects. [J Pediatr Ophthalmol Strabismus. 2022;59(2):128-135.].

Novel "T-Dimension" Therapies for Pediatric Optic Pathway Glioma: A Timely, Targeted, and Tailored Treatment Trend

INTRODUCTION

Novel targeted and tailored therapies can substantially improve the prognosis for optic pathway glioma (OPG), especially when implemented in a timely manner. However, their tremendous potential remains underestimated. Therefore, in this study, we provide an updated overview of the clinical trials, current trends, and future perspectives for OPG's novel therapeutic strategies.

METHODS

We completed an extensive literature review using the PubMed, MEDLINE, and ClinicalTrials.gov databases. We analyzed and reported the data following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

Thioguanine, procarbazine, lomustine, and vincristine/vinblastine, as well as cisplatin-etoposide, provided excellent results in advanced-phase trials. Selumetinib and trametinib, two oral MEK inhibitors, have been approved for recurrent or refractory OPGs in association with the angiogenetic inhibitor bevacizumab. Among the mTOR inhibitors, everolimus and sirolimus showed the best results. Stereotactic radiosurgery and proton beam radiation therapy have advantages over conventional radiotherapy regimens. Timely treatment is imperative for acute visual symptoms with evidence of tumor progression. This latest evidence can help define a novel "T-Dimension" for pediatric OPG therapies.

CONCLUSION

The novel "T-Dimension" for pediatric OPGs is based on recent evidence-based treatments, including combination chemotherapy regimens, molecular targeted therapies, stereotactic radiosurgery, and proton beam radiation therapy. Additional clinical trials are essential for validating each of these new therapies.

The RASopathies: Biology, genetics and therapeutic options

The RASopathies are a group of genetic diseases in which the Ras/MAPK signaling pathway is inappropriately activated as a result of mutations in genes encoding proteins within this pathway. As their causative mutations have been identified, this group of diseases has expanded to include neurofibromatosis type 1 (NF1), Legius syndrome, Noonan syndrome, CBL syndrome, Noonan syndrome-like disorder with loose anagen hair, Noonan syndrome with multiple lentigines, Costello syndrome, cardiofaciocutaneous syndrome, gingival fibromatosis and capillary malformation-arteriovenous malformation syndrome. Many of these genetic disorders share clinical features in common such as abnormal facies, short stature, varying degrees of cognitive impairment, cardiovascular abnormalities, skeletal abnormalities and a predisposition to develop benign and malignant neoplasms. Others are more dissimilar, even though their mutations are in the same gene that is mutated in a different RASopathy. Here, we describe the clinical features of each RASopathy and contrast them with the other RASopathies. We discuss the genetics of these disorders, including the causative mutations for each RASopathy, the impact that these mutations have on the function of an individual protein and how this dysregulates the Ras/MAPK signaling pathway. As several of these individual disorders are genetically heterogeneous, we also consider the different genes that can be mutated to produce disease with the same phenotype. We also discuss how our growing understanding of dysregulated Ras/MAPK signaling had led to the development of new therapeutic agents and what work will be critically important in the future to improve the lives of patients with RASopathies.

Vision Outcomes for Pediatric Patients With Optic Pathway Gliomas Associated With Neurofibromatosis Type I: A Systematic Review of the Clinical Evidence

Children with neurofibromatosis type I (NF1) have a higher predisposition for low-grade astrocytomas of the optic pathway, commonly referred to as optic pathway gliomas (OPGs). OPGs can result in visual deterioration. Treatment outcomes in OPG-NF1 management are often reported around tumor stabilization. We sought to compare vision outcomes associated with different OPG treatment strategies to inform about this important functional metric. A meta-analysis exploring the different modalities to treat children with OPG-NF1 was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using multiple databases. Of the 113 articles identified in the search, 23 full text articles, representing 564 patients, were included for review. These articles included retrospective, prospective, and randomized controlled studies on observation (n=9), chemotherapy (n=19), radiation therapy (n=6), and surgery (n=7). Of the patients undergoing observation, 87% (60/69) demonstrated stable acuity. In the chemotherapy studies, 27.3% (72/264) demonstrated improved acuity/visual field and/or visual-evoked potential amplitudes, 39.4% (104/264) stable acuity, and 33.3% (88/264) deterioration. Both the radiation and surgical treatments reported worsening acuity at 90.9% (10/11) and 73.3% (11/15), respectively. Causal associations are not known. Indications for and timing of treatment choice warrant larger scale study to provide further understanding.

NF1 optic pathway glioma: analyzing risk factors for visual outcome and indications to treat

BACKGROUND

The aim of the project was to identify risk factors associated with visual progression and treatment indications in pediatric patients with neurofibromatosis type 1 associated optic pathway glioma (NF1-OPG).

METHODS

A multidisciplinary expert group consisting of ophthalmologists, pediatric neuro-oncologists, neurofibromatosis specialists, and neuro-radiologists involved in therapy trials assembled a cohort of children with NF1-OPG from 6 European countries with complete clinical, imaging, and visual outcome datasets. Using methods developed during a consensus workshop, visual and imaging data were reviewed by the expert team and analyzed to identify associations between factors at diagnosis with visual and imaging outcomes.

RESULTS

Eighty-three patients (37 males, 46 females, mean age 5.1 ± 2.6 y; 1-13.1 y) registered in the European treatment trial SIOP LGG-2004 (recruited 2004-2012) were included. They were either observed or treated (at diagnosis/after follow-up).In multivariable analysis, factors present at diagnosis associated with adverse visual outcomes included: multiple visual signs and symptoms (adjusted odds ratio [adjOR]: 8.33; 95% CI: 1.9-36.45), abnormal visual behavior (adjOR: 4.15; 95% CI: 1.20-14.34), new onset of visual symptoms (adjOR: 4.04; 95% CI: 1.26-12.95), and optic atrophy (adjOR: 3.73; 95% CI: 1.13-12.53). Squint, posterior visual pathway tumor involvement, and bilateral pathway tumor involvement showed borderline significance. Treatment appeared to reduce tumor size but improved vision in only 10/45 treated patients. Children with visual deterioration after primary observation are more likely to improve with treatment than children treated at diagnosis.

CONCLUSIONS

The analysis identified the importance of symptomatology, optic atrophy, and history of vision loss as predictive factors for poor visual outcomes in children with NF1-OPG.

Optic Nerve Gliomas

Objectives  To describe the diagnostic and management features of optic nerve gliomas. Design  Literature review. Results  Optic nerve gliomas are generally benign in the pediatric age group although they are usually malignant and aggressive in adults. As such, the mechanisms by which these lesions are diagnosed, the systemic implications, the goals of intervention, and the nature of therapeutic management all differ between these tumors. Conclusions  This article addresses these lesions and discusses the diagnostic and therapeutic paradigms by which they may be approached.

Neurofibromatosis Type 1-Associated Optic Pathway Glioma in Children: A Follow-Up of 10 Years or More

PURPOSE

This study reports on neurofibromatosis type 1 (NF1)-associated optic pathway gliomas (OPGs) and a follow-up period of at least 10 years in a cohort of children. OPGs are a common manifestation of NF1 and can cause significant visual morbidity. Long-term follow-up in children with NF1-associated OPGs has not been reported previously.

DESIGN

Retrospective observational case series.

METHODS

This study included children with a documented follow-up of at least 10 years. Three final outcomes were evaluated: visual acuity (VA) per eye (i.e., in the more severely affected eye), VA per patient (i.e., VA when both eyes were open), and the presence of optic nerve head pallor.

RESULTS

A total of 45 children were included, followed for a mean of 14 years (range, 10-21 years). At the end of follow-up, abnormal VA (considered moderate to severe impairment) in the more severely affected eye was present in 36% of the patients and in both eyes in 11%. Optic nerve head pallor of 1 or both nerves was present in 62%. In multivariate analysis, only initial VA and optic nerve head appearance at presentation were found to predict the final outcomes. All patients, except for 1, were asymptomatic at presentation and had normal VA and nerves that appeared normal, preserved their good vision in both eyes. Only 1 patient, who had normal VA and normal appearing nerves at presentation, had moderate to severe VA loss at long term follow-up.

CONCLUSIONS

In this study, children with NF1-associated OPG whose examination signs and symptoms were normal had a normal initial examination and excellent long-term visual and anatomical outcomes. VA and the appearance of the optic nerve head at presentation predict long-term outcome.

Management of Children with Optic Gliomas and Neurofibromatosis Type 1

Optic pathway gliomas (OPG) are a common cancer in children with neurofibromatosis type 1. OPGs can cause clinical symptoms such as reduction of visual acuity, alterations of the visual field, pallor of the optical papilla, strabismus, endocrinological alterations up to diencephalic syndrome.The current guidelines provide for wait and see as the main approach if the tumor is not causing visual deterioration and adopting treatment only in the event of significant impairment of the visual function. Therefore, it is essential to early detect the visual deterioration changes as well as the identification of children eligible for treatment.

Visual field outcomes in children treated for neurofibromatosis type 1-associated optic pathway gliomas: a multicenter retrospective study

BACKGROUND

Optic pathway gliomas associated with neurofibromatosis type 1 (NF1-OPGs) may adversely affect visual acuity, but data regarding visual field (VF) outcomes after treatment in children are limited. The purpose of this study was to investigate the effects of NF1-OPGs on VF function in a large cohort of children after treatment with chemotherapy.

METHODS

We performed a retrospective, international, multicenter study of VF outcomes in patients treated with chemotherapy for NF1-OPGs.

RESULTS

A total of 25 participants underwent VF testing using formal perimetric techniques. At the end of treatment, 19 participants (76%) had persistent VF deficits. Formal VF testing was available for 16 participants (64%) at initiation and completion of treatment. Of the 16 children who underwent VF testing at initiation and completion of treatment, 7 (44%) showed stability of VF changes, 3 (19%) showed improvement of VF function, and 6 (38%) had worsening of VFs. Improvement or worsening of VF outcome did not always correlate with visual acuity outcome. Posterior tumor location involving the optic tracts and radiations was associated with more frequent and more profound VF defects.

CONCLUSIONS

In our study cohort, children undergoing initial chemotherapy for NF1-OPGs had a high prevalence of VF loss, which could be independent of visual acuity loss. A larger, prospective study is necessary to fully determine the prevalence of VF loss and the effects of chemotherapy on VF outcomes in children with NF1-OPGs.

Visual function tests including the role of optical coherence tomography in neurofibromatosis 1

Optic pathway glioma (OPG) is a common and significant complication of neurofibromatosis 1 (NF-1) that might lead to vision loss. The main reason to treat OPG is to preserve vision. Tumor location along the visual pathway largely dictates the presenting signs and symptoms. Clinical ophthalmic evaluation is focused on optic nerve functions including evaluation of pupils' reaction to light, visual acuity, color vision, and visual field, as well as optic nerve appearance. An important relatively new ancillary test is optic coherence tomography (OCT) that measures the volume of retinal nerve fiber layer around the optic nerve and the ganglion cell layer-inner plexiform layer (GCL-IPL) of the macula, both proved to be strongly associated with losing vision in OPG. Accurate evaluation of vision functions plays a critical role in the decision of treatment. In this review, we describe the ophthalmological assessment including new biomarkers in clinical use. We also outline prognostic factors and current recommendations for surveillance and indications for treatment.

Neurofibromatosis 1-associated optic pathway gliomas

BACKGROUND

Optic Pathway Gliomas (OPG) are the most common brain tumor in Neurofibromatosis 1 patients (NF1). They are found along the optic pathway and may involve the optic nerves, chiasm, retro-chiasmatic structures, and the optic radiations. NF1 associate OPG (NF1-OPG) have variable presentation, disease course and response to treatment. The optimal management is patient-specific and should be tailored by a multidisciplinary team. Age, sex, histology, and molecular markers may be important factors in the individualized decision-making process. Chemotherapy is the first-line treatment in cases of progressive tumors, and visual preservation is the main goal of treatment.

PURPOSE

In this paper we will review the disease, practical management, and recent advances of NF1-OPG.

Role of visual evoked potentials and optical coherence tomography in the screening for optic pathway gliomas in patients with neurofibromatosis type I

PURPOSE

The purpose of the present study was to compare visual function assessment, visual evoked potential, and optical coherence tomography with measurement of retinal nerve fiber layer thickness for the diagnosis of optic pathway glioma in children with neurofibromatosis type 1.

METHODS

This retrospective observational study included patients with neurofibromatosis type 1 who underwent brain magnetic resonance imaging scan, visual evoked potential study, and peripapillary retinal nerve fiber layer evaluation by optical coherence tomography. Patients were tested with pattern-reversal visual evoked potential and with flash visual evoked potential in case of poor cooperation. Optical coherence tomography was performed with HRA Spectralis (Heidelberg Engineering, Heidelberg, Germany). The area under the curve of receiver operating characteristic curves was used to evaluate the accuracy of each parameter for diagnosing optic pathway glioma.

RESULTS

In all, 110 patients with neurofibromatosis type 1 were included in the study. Fifty of them had an optic pathway glioma diagnosed with magnetic resonance imaging, while 60 did not. Global retinal nerve fiber layer thickness demonstrated the highest diagnostic power for discriminating patients with and without optic pathway glioma (area under the curve = 0.758, sensitivity = 65.3%, specificity = 83.3%), followed visual acuity (area under the curve = 0.723, sensitivity = 51.1%, specificity = 91.7%) and P100 of visual evoked potential (area under the curve = 0.712, sensitivity = 69.6%, specificity = 63.8%).

CONCLUSION

The results of the present study showed that the measurement of retinal nerve fiber layer thickness was the most efficient test for discriminating patients with and without optic pathway glioma. Brain magnetic resonance imaging remains the gold standard to confirm the diagnosis of optic pathway glioma. Longitudinal studies are required to define if the early detection of tumors with optical coherence tomography could prevent vision loss and morbidity.

En-Bloc Resection Versus Resection After Evacuation and Suction of the Content for Orbital Optic Nerve Glioma Causing Visual Loss and Disfiguring Proptosis

PURPOSE

To evaluate the surgical outcomes of two different techniques of resection for optic nerve gliomas confined to the intra-orbital segment.

METHODS

This prospective, comparable, clinical interventional case series was conducted at the orbital clinic of Assiut University Hospital, the referral centre of Upper Egypt in the period between 2006 and 2018. The study included 10 children with optic nerve gliomas confined to the intra-orbital part without intracanalicular or intracranial extension and causing severe visual loss and disfiguring proptosis. In all cases, lateral orbitotomy was performed to expose the mass. In 5 cases (group A), the glioma was resected en-bloc. In 5 cases (group B), a new technique of resection was introduced. The wall of the glioma was incised, the content was evacuated and suctioned and followed by resection under good visualization of the markedly reduced mass in size.

RESULTS

In the 2 groups, no tumour regrowth was reported during the follow-up period of 3-12 years. In group A, the 5 cases developed postoperative third nerve damage with paralytic ptosis and one case had severe neurotrophic keratitis ended by dense corneal opacity. In group B, a healthy ipsilateral eye was preserved in all cases and no one case developed postoperative paralytic ptosis.

CONCLUSIONS

Reduction of size of an intra-orbital optic nerve glioma by evacuation and suction of the content before resection is highly recommended. This makes the surgical field during resection more visible and minimizes the possibility of third or other nerves damage.

An Update on Neurofibromatosis Type 1-Associated Gliomas

Neurofibromatosis type 1 (NF1) is an autosomal dominant tumor predisposition syndrome that affects children and adults. Individuals with NF1 are at high risk for central nervous system neoplasms including gliomas. The purpose of this review is to discuss the spectrum of intracranial gliomas arising in individuals with NF1 with a focus on recent preclinical and clinical data. In this review, possible mechanisms of gliomagenesis are discussed, including the contribution of different signaling pathways and tumor microenvironment. Furthermore, we discuss the recent notable advances in the developing therapeutic landscape for NF1-associated gliomas including clinical trials and collaborative efforts.

Brain tumors in Neurofibromatosis type 1

As a cancer predisposition syndrome, individuals with neurofibromatosis type 1 (NF1) are at increased risk for the development of both benign and malignant tumors. One of the most common locations for these cancers is the central nervous system, where low-grade gliomas predominate in children. During early childhood, gliomas affecting the optic pathway are most frequently encountered, whereas gliomas of the brainstem and other locations are observed in slightly older children. In contrast, the majority of gliomas arising in adults with NF1 are malignant cancers, typically glioblastoma, involving the cerebral hemispheres. Our understanding of the pathogenesis of NF1-associated gliomas has been significantly advanced through the use of genetically engineered mice, yielding new targets for therapeutic drug design and evaluation. In addition, Nf1 murine glioma models have served as instructive platforms for defining the cell of origin of these tumors, elucidating the critical role of the tumor microenvironment in determining tumor growth and vision loss, and determining how cancer risk factors (sex, germline NF1 mutation) impact on glioma formation and progression. Moreover, these preclinical models have permitted early phase analysis of promising drugs that reduce tumor growth and attenuate vision loss, as an initial step prior to translation to human clinical trials.

Long-term visual acuity in patients with optic pathway glioma treated during childhood with up-front BB-SFOP chemotherapy-Analysis of a French pediatric historical cohort

Background

Visual outcome is one of the main issues in the treatment of optic pathway glioma in childhood. Although the prognostic factors of low vision have been discussed extensively, no reliable indicators for visual loss exist. Therefore, we aimed to define initial and evolving factors associated with long-term vision loss.

Methods

We conducted a multicenter historical cohort study of children treated in France with up-front BB-SFOP chemotherapy between 1990 and 2004. Visual acuity performed at the long-term follow-up visit or within 6 months prior was analyzed. Logistic regression analysis was used to estimate the effects of clinical and radiological factors on long-term visual outcome.

Findings

Of the 180 patients in the cohort, long-term visual acuity data were available for 132 (73.3%) patients (median follow-up: 14.2 years; range: 6.1–25.6). At the last follow-up, 61/132 patients (46.2%) had impaired vision, and 35 of these patients (57.3%) were partially sighted or blind. Multivariate analysis showed that factors associated with a worse prognosis for long-term visual acuity were an age at diagnosis of < 1 year (OR 3.5 [95% CI: 1.1–11.2], p = 0.04), tumor extent (OR 4.7 [95% CI: 1.2–19.9], p = 0.03), intracranial hypertension requiring one or more surgical procedures (OR 5.6 [95% CI: 1.8–18.4], p = 0.003), and the need for additional treatment after initial BB-SFOP chemotherapy (OR 3.5 [95% CI: 1.1–11.9], p = 0.04). NF1 status did not appear as a prognostic factor, but in non-NF1 patients, a decrease in tumor volume with contrast enhancement after BB-SFOP chemotherapy was directly associated with a better visual prognosis (OR 0.8 [95% CI: 0.8–0.9], p = 0.04).

Interpretation

Our study confirms that a large proportion of children with optic pathway glioma have poor long-term outcomes of visual acuity. These data suggest new prognostic factors for visual acuity, but these results need to be confirmed further by large- and international-scale studies.

Comparison of multi-shot and single shot echo-planar diffusion tensor techniques for the optic pathway in patients with neurofibromatosis type 1

PURPOSE

Diffusion tensor imaging (DTI) may be helpful in assessing optic pathway integrity as a marker for treatment in neurofibromatosis type 1 (NF1) patients with optic gliomas (OG). However, susceptibility artifacts are common in typical single-shot echo planar imaging (ssDTI). A readout-segmented multi-shot EPI technique (rsDTI) was utilized to minimize susceptibility distortions of the skull base and improve quantitative metrics.

METHODS

Healthy controls, children with NF1 without OG, and NF1 with OG ± visual symptoms were included. All subjects were scanned with both rsDTI and ssDTI sequences sequentially. Diffusion metrics and deterministic fiber tracking were calculated. Tract count, volume, and length were also compared by a two-factor mixed ANOVA.

RESULTS

Five healthy controls, 7 NF1 children without OG, and 12 NF1 children with OG were imaged. Six OG patients had visual symptoms. Four subjects had no detectable optic pathway fibers on ssDTI due to susceptibility, for which rsDTI was able to delineate. Tract count (p < 0.001), tract volume (p < 0.001), and FA (P < 0.001) were significantly higher for rsDTI versus ssDTI for all subjects. MD (p < 0.001) and RD (p < 0.001) were significantly lower for rsDTI vs ssDTI. Finally, MD, AD, and RD had a significantly lower difference in NF1 children with visual symptoms compared to NF1 children without visual symptoms only on ssDTI scans.

CONCLUSION

DTI with readout-segmented multi-shot EPI technique can better visualize the optic pathway and allow more confident measurements of anisotropy in NF1 patients. This is shown by a significant increase in FA, tract count, and volume with rsDTI versus ssDTI.

Surveillance magnetic resonance imaging for isolated optic pathway gliomas: is gadolinium necessary?

BACKGROUND

Pediatric optic pathway gliomas are typically indolent but have a variable clinical course. Treatment is dictated by symptoms and changes on contrast-enhanced MRI examinations. Gadolinium retention in children has motivated parsimonious use of gadolinium-based contrast agents.

OBJECTIVES

To determine surveillance MR factors that motivate changes in tumor-directed therapies and extrapolate cost-efficacy of a non-contrast follow-up protocol.

MATERIALS AND METHODS

Using an imaging database search we identified children with isolated optic pathway gliomas and ≥3 follow-up contrast-enhanced MRIs. We reviewed medical records and imaging for: (1) coincident changes on contrast-enhanced MRI and tumor-directed therapy, (2) demographics and duration of follow-up, (3) motivations for intervention, (4) assessment of gadolinium-based contrast agents' utility and (5) health care utilization data. We assessed cost impact in terms of relative value unit (RVU) burden.

RESULTS

We included 17 neurofibromatosis type 1 (NF1) and 21 non-NF1 patients who underwent a median 16.9 and 24.3 cumulative contrast-enhanced MR exams over 7.7 years and 8.1 years of follow-up, respectively. Eight children (one with NF1) had intervention based on contrast-enhanced MR findings alone. For these eight, increased tumor size was the only common feature, and it was apparent on non-contrast T2 sequences. For the median patient, a non-contrast follow-up protocol could result in 15.9 (NF1) and 23.3 (non-NF1) fewer gadolinium-based contrast agent administrations, and a 39% lower yearly RVU burden.

CONCLUSION

Pediatric patients with isolated optic pathway gliomas undergo a large number of routine contrast-enhanced MR follow-up exams. Gadolinium might not be needed for these exams to inform management decisions. Secondary benefits of a non-contrast follow-up protocol include decreased cost and risk to the patient.

Recent Advances in the Diagnosis and Pathogenesis of Neurofibromatosis Type 1 (NF1)-associated Peripheral Nervous System Neoplasms

The diagnosis of a neurofibroma or a malignant peripheral nerve sheath tumor (MPNST) often raises the question of whether the patient has the genetic disorder neurofibromatosis type 1 (NF1) as well as how this will impact the patient's outcome, what their risk is for developing additional neoplasms and whether treatment options differ for NF1-associated and sporadic peripheral nerve sheath tumors. Establishing a diagnosis of NF1 is challenging as this disorder has numerous neoplastic and non-neoplastic manifestations which are variably present in individual patients. Further, other genetic diseases affecting the Ras signaling cascade (RASopathies) mimic many of the clinical features of NF1. Here, we review the clinical manifestations of NF1 and compare and contrast them with those of the RASopathies. We also consider current approaches to genetic testing for germline NF1 mutations. We then focus on NF1-associated neurofibromas, considering first the complicated clinical behavior and pathology of these neoplasms and then discussing our current understanding of the genomic abnormalities that drive their pathogenesis, including the mutations encountered in atypical neurofibromas. As several neurofibroma subtypes are capable of undergoing malignant transformation to become MPNSTs, we compare and contrast patient outcomes in sporadic, NF1-associated and radiation-induced MPNSTs, and review the challenging pathology of these lesions. The mutations involved in neurofibroma-MPNST progression, including the recent identification of mutations affecting epigenetic regulators, are then considered. Finally, we explore how our current understanding of neurofibroma and MPNST pathogenesis is informing the design of new therapies for these neoplasms.

Investigation of retinal nerve fiber layer thickness and ganglion cell layer-inner plexiform layer thickness in patients with optic pathway gliomas

PURPOSE

This study aimed to compare the optical coherence tomography (OCT) findings of optic pathway glioma (OPG) patients (sporadic or secondary to neurofibromatosis type 1, NF1) with NF1 without OPG patients and healthy controls.

METHODS

This was a prospective, case-control study in which 27 patients (13 with OPGs and 14 with NF1 without OPGs) and 13 control subjects were included. The retinal nerve fiber layer (RNFL) thickness, macular thickness, and ganglion cell layer-inner plexiform layer (GCL-IPL) thickness findings measured using OCT and the results were compared between the groups.

RESULTS

The macular thickness was significantly lower in the OPG group than in the control group and the NF1 patients without OPGs group (p < 0.001). The GCL-IPL thickness was lower in OPG group than in the control group and the NF1 patients without OPG group (p < 0.001). The RNFL thickness was lower in the OPG group than in the control group and the NF1 patients without OPG group (p < 0.001). There was a statistically significantly negative correlation between the visual acuity (log of the minimum angle of resolution, logMAR) and all the other parameters (macular, RNFL, and GCL-IPL thicknesses). All the parameters were found to positively correlate with each other.

CONCLUSIONS

OCT measurements (macular thickness, RNFL, and GCL-IPL thicknesses) can be used to monitor the disease in those patients with suspected OPGs; however, this should be verified with a larger case series.

Optic Pathway Gliomas in Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is one of the most common brain tumor predisposition syndromes, in which affected children are prone to the development of low-grade gliomas. While NF1-associated gliomas can be found in several brain regions, the majority arise in the optic nerves, chiasm, tracts, and radiations (optic pathway gliomas; OPGs). Owing to their location, 35-50% of affected children present with reduced visual acuity. Unfortunately, despite tumor stabilization following chemotherapy, vision does not improve in most children. For this reasons, more effective therapies are being sought that reflect a deeper understanding of the NF1 gene and the use of authenticated Nf1 genetically-engineered mouse strains. The implementation of these models for drug discovery and validation has galvanized molecularly-targeted clinical trials in children with NF1-OPG. Future research focused on defining the cellular and molecular factors that underlie optic glioma development and progression also has the potential to provide personalized risk assessment strategies for this pediatric population.

Ophthalmic manifestations in neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is a relatively common multisystemic inherited disease and has been extensively studied by multiple disciplines. Although genetic testing and confirmation are available, NF1 remains a clinical diagnosis. Many manifestations of NF1 involve the eye and orbit, and the ophthalmologist, therefore, plays a significant role in the diagnosis and treatment of NF1 patients. Improvements in diagnostic and imaging instruments have provided new insight to study the ophthalmic manifestations of the disease. We provide a comprehensive and up-to-date overview of the ocular and orbital manifestations of NF1.

Optic Pathway Gliomas in Neurofibromatosis Type 1: An Update: Surveillance, Treatment Indications, and Biomarkers of Vision

Optic pathway gliomas (OPGs) occur in 15%-20% of children with neurofibromatosis type 1 (NF1), leading to visual deficits in fewer than half of these individuals. The goal of chemotherapy is to preserve vision, but vision loss in NF1-associated OPG can be unpredictable. Determining which child would benefit from chemotherapy and, equally important, which child is better observed without treatment can be difficult. Unfortunately, despite frequent imaging and ophthalmologic evaluations, some children experience progressive vision loss before treatment. Indications for chemotherapy usually are based on a comprehensive, quantitative assessment of vision, but reliable vision evaluation can be challenging in young children with NF1-OPG. The ability to identify and predict impending vision loss could potentially improve management decisions and visual outcomes. To address this challenge, ophthalmologic, electrophysiologic, and imaging biomarkers of vision in NF1-OPG have been proposed. We review current recommendations for the surveillance of children at risk for NF1-OPG, outline guidelines for initiating therapy, and describe the utility of proposed biomarkers for vision.

Clinical Presentation and Outcome of Patients With Optic Pathway Glioma

BACKGROUND

Optic pathway gliomas (OPGs) occur sporadically or in patients with neurofibromatosis type 1 (NF1). The purpose of this study was to evaluate the clinical presentation at diagnosis and at progression of patients with OPGs.

METHODS

We conducted a chart review of patients with OPGs diagnosed in a single center over a period of 15 years. Demographic data including age, sex, NF1 status, clinical presentation, and outcome were collected.

RESULTS

Of the 40 patients who were identified, 23 had sporadic tumors (57.5%) and 17 had NF1-related tumors (42.5%). Among the children with NF1, there was a significant overrepresentation of girls (82.3%) (P = 0.02), while among the children without NF1, there were slightly more boys (56.5%) than girls (43.5%). The presence of nystagmus was strongly associated with sporadic optic pathway gliomas. Poor visual outcome was related to tumor affecting both optic pathways, hydrocephalus at diagnosis, and optic nerve atrophy. Of the 40 patients, five died of OPG complications (12.5%) and all had sporadic tumors.

CONCLUSIONS

Our cohort is one of the largest with OPGs and a detailed description of the clinical presentation both at diagnosis and at progression. We observed a significant difference between sporadic and NF1 optic pathway gliomas in terms of demographics, clinical presentation, and outcome.

Primary Gliosarcoma of the Optic Nerve: A Unique Adult Optic Pathway Glioma

A 90-year-old woman presented with 1-year history of right-sided progressive proptosis, neovascular glaucoma, blindness, and worsening ocular pain. No funduscopic examination was possible because of a corneal opacity. Head CT scan without contrast demonstrated a heterogeneous 4.1 cm (anterior-posterior) by 1.7 cm (transverse) cylindrical mass arising in the right optic nerve and extending from the retrobulbar globe to the optic canal. She underwent palliative enucleation with subtotal resection of the orbital optic nerve and tumor. Pathological examination showed effacement of the optic nerve by an infiltrative high-grade glial neoplasm with biphasic sarcomeric differentiation. Invasion into the uvea and retina was present. The neoplasm was negative for melan-A, HMB45, tyrosinase, synaptophysin, smooth muscle actin, and epithelial membrane antigen. The glioma had strongly intense, but patchy immunopositivity for glial fibrillary acidic protein. Multiple foci of neoplastic cells had pericellular reticulin staining. The overall features were diagnostic of a gliosarcoma (World Health Organization grade IV) of the optic nerve. Postoperative MRI demonstrated postsurgical changes and residual gliosarcoma with extension into the optic chiasm. The patient died 2 and a half months after her enucleation surgery at her nursing home. Autopsy was unavailable due to the caregiver wishes, making a definitive cause of death unknown. Gliosarcoma is a rare variant of glioblastoma, and this is the first documented case presenting as a primary neoplasm of the optic nerve.

Natural history of optic pathway gliomas in a cohort of unselected patients affected by Neurofibromatosis 1

Optic pathway glioma (OPG) represents the most common central nervous system tumor in children with Neurofibromatosis type-1 (NF1). Although overall survival is usually good, no clear prognostic factors have been identified so far. We assessed the natural history of OPG in a cohort of unselected patients affected by NF1. We retrospectively evaluated 414 consecutive patients affected by NF1 and referred to our NF1 clinic before age 6. Average follow-up was 11.9 years: 52 out of 414 patients had OPG with a total cumulative incidence of 15.4% at age 15 (Kaplan-Meier estimate) and a statistically significant difference according to sex. Brain and orbit MRI was performed in 44.7% of patients: 34.6% for screening purposes and 65.4% because of the presence of neurological, ocular or other symptoms. OPG was diagnosed in 12.5% of cases in the first group, whereas in 36.4% in the latter group (p = 0.001). Clinical management was conservative in most patients, while 8 of them underwent therapy mainly because of visual deterioration. OPG was diagnosed earlier in treated patients, but the difference was not statistically significant. Conversely, all patients who underwent screening MRI had normal visual outcome. In conclusion, OPG location does not correlate with need for treatment; female patients were more frequently affected by OPG but not more frequently treated. OPG diagnosis by screening MRI does not affect the natural history of the tumor.

Optic Pathway Gliomas Secondary to Neurofibromatosis Type 1

Children with neurofibromatosis type 1 frequently manifest optic pathway gliomas-low-grade gliomas intrinsic to the visual pathway. This review describes the molecular and genetic mechanisms driving optic pathway gliomas as well as the clinical symptoms of this relatively common genetic condition. Recommendations for clinical management and descriptions of the newest imaging techniques are discussed.

A Comprehensive Review of Pediatric Tumors and Associated Cancer Predisposition Syndromes

An understanding of the role of inherited cancer predisposition syndromes in pediatric tumor diagnoses continues to develop as more information is learned through the application of genomic technology. Identifying patients and their relatives at an increased risk for developing cancer is an important step in the care of this patient population. The purpose of this review is to highlight various tumor types that arise in the pediatric population and the cancer predisposition syndromes associated with those tumors. The review serves as a guide for recognizing genes and conditions to consider when a pediatric cancer referral presents to the genetics clinic.

Surgical Management of Pilocytic Astrocytoma of the Optic Nerve: A Case Report and Review of the Literature

Optic nerve astrocytomas (ONAs) are frequent types of optic nerve gliomas (ONGs), which can affect the visual pathway. An 18-year-old male patient was admitted to our department with right-sided intraorbital/retrobulbar swelling, which progressively grew over several months. Clinical examination showed right-sided diplopia, mydriasis, low visual acuity (0.4), exophthalmus (3 cm), epiphora, and severe retrobulbar pain. There was a family history of high-grade (IV) astrocytomas in which two of the family members died due to the disease. Preoperative MRI scan revealed a soft tissue mass around the retrobulbar area of the right eye with intact orbital bony walls. Surgery was performed whereby it was dissected freely from the muscles and was separated from the optic nerve and the globe. Histopathologic analysis confirmed a benign astrocytoma. The follow-up examination revealed no recurrent or residual tumor. A systemic review of the literature indicates that early diagnosis and experienced multidisciplinary management are required in case of unilateral, resectable forms of ONAs with no distant metastasis, in order to provide a long-time survival of patients. Surgical intervention of unilateral ONAs is a relatively safe procedure, allowing complete or partial tumor removal with minimal morbidity and low recurrence rate.

Optic Gliomas in Neurofibromatosis Type 1

PURPOSE

To examine the incidence, presentation, and outcome of optic gliomas in children with neurofibromatosis type 1 (NF1) in Southern California Kaiser Permanente.

METHODS

The authors queried the Southern California Kaiser Permanente electronic medical record database to find patients diagnosed as having NF1. Genetics, ophthalmology, and imaging medical records of patients with optic glioma were reviewed.

RESULTS

A total of 708 patients younger than 21 years had a diagnosis of NF1 in Southern California Kaiser Permanente and 30 (4.2%) had a diagnosis of optic glioma. The average age of diagnosis was 5 years, with a range of 18 months to 12 years. Half (15 of 30) of the patients diagnosed as having optic glioma presented with symptoms (eg, vision loss, proptosis, and precocious puberty). Eight of 15 of the symptomatic patients were treated with surgery and/or chemotherapy. Symptomatic children were diagnosed later than those diagnosed through routine screening (5.7 vs 3.9 years old). The oldest child presented with symptoms at age 12 years. One asymptomatic patient had prophylactic chemotherapy. Sixty-three percent (19 of 30) of the gliomas were bilateral, 23% (7 of 30) were right-sided, and 13% (4 of 30) were left-sided. Fifty-three percent (17 of 30) of the gliomas involved the optic chiasm.

CONCLUSIONS

Screening practices for optic glioma are inconsistent. Most children with NF1 at risk for optic glioma do not have even one visit with an ophthalmologist. Children with NF1 can develop asymptomatic optic glioma as early as age 1 year. Annual ophthalmologic examination and screening for precocious puberty in children with NF1 is important for early diagnosis of optic gliomas and may reduce morbidity. [J Pediatr Ophthalmol Strabismus. 2016;53(6):334-338.].

High-Dose Intravenous Vitamin C Treatment of a Child with Neurofibromatosis Type 1 and Optic Pathway Glioma: A Case Report

Patient: Male, 1

Final Diagnosis: Optic glioma

Symptoms: Visual problems

Medication: —

Clinical Procedure: Intravenous vitamin C

Specialty: Oncology

Systematic MRI in NF1 children under six years of age for the diagnosis of optic pathway gliomas. Study and outcome of a French cohort

BACKGROUND/PURPOSE

Optic pathway glioma (OPG) is the most common central nervous system tumor in children with neurofibromatosis type 1 (NF1), affecting 15-20% of patients. We reviewed the medical records of children systematically screened by ophthalmologic and MRI examinations to determine the influence of screening on the therapeutic management of children with OPG.

METHODS

Data were collected on 306 newly diagnosed cases screened with systematic MRI from January 2001 to July 2007. In the OPG group, we distinguished the asymptomatic or symptomatic groups according to their initial status.

RESULTS

Forty-five patients had confirmed OPG (14.7%). Thirty-six patients (80%) were asymptomatic and nine (20%) were symptomatic at the time of diagnosis with visual symptoms in six cases. The average age at OPG diagnosis was 3.4 years with six patients (13%) over six years old. Average follow-up was 7.7 years. Progression was observed in 16 cases (35%). Most patient conditions were managed conservatively (87%). Six children (13%) were treated with chemotherapy due to worsening visual function. All of these children had severe or mild visual impairment at the end of follow-up.

CONCLUSION

Our study does not support a clear benefit of systematic MRI screening in NF1 children under six years old. Systematic neuroimaging in our study did not influence therapeutic management. Although OPG diagnosis was made early, treatment with chemotherapy did not improve the final visual outcome. If MRI remains the best tool for the diagnosis of cerebral and spinal pathologies in the NF1 population, our current study questions the usefulness of systematic MRI screening for OPG diagnosis. Conversely, this study suggests that the indication of neuroimaging should be dictated by the results of annual clinical and ophthalmological assessments.