Neurofibromatosis: an update of ophthalmic characteristics and applications of optical coherence tomography

Neurofibromatosis Type 1-Retinal Alterations Detectable with Optical Coherence Tomography Angiography

Neurofibromatosis type 1 (NF 1) is a multisystemic genetic disorder involving aberrant proliferation of multiple tissues of a neural crest origin. It represents a tumor predisposition syndrome characterized by a wide range of clinical manifestations, such as benign tumors, which primarily affect the skin and the nervous system. The most frequent clinical signs of NF 1 include café-au-lait spots all over the surface of the skin and axillary freckling; however, these signs can be accompanied by more severe manifestations such as the growth of both benign and malignant nervous system tumors and skeletal dysplasia, as well as a wide range of ocular manifestations. We report the rare case of retinal microvascular alterations and choroidal nodules in a 15 year old male patient with NF 1, detectable on optical coherence tomography angiography (OCTA). The hyperreflective choroidal nodules modified the profile of the choroidal vasculature. The retinal microvascular alterations in the form of clustered capillaries were detected in the superficial capillary plexus located nasally to the macular region. Retinal vascular abnormalities undetectable on fundus photography or fundoscopy can be present in patients with NF 1. Indirect ophthalmoscopy of our study patient was unremarkable. However, retinal vascular abnormalities were seen on OCTA scans in the superficial capillary plexus and choroidal nodules were detected on raster OCT scans. OCTA represents a useful imaging technique for detecting retinal microvascular abnormalities, which can be considered additional distinctive signs of NF 1.

Secondary developmental glaucoma

The basic pathophysiology of all childhood glaucoma results from impaired outflow through the trabecular meshwork. Anterior Segment Dysgeneses (ASD) are a group of nonacquired anomalies associated with secondary developmental glaucoma, characterized by impaired development of the structures of the anterior segment. Many genes impact the development of the anterior segment. The cause of the development of the abnormalities is thought to be multifactorial. Molecular research has helped our understanding of the molecular basis of ASD and the developmental mechanisms underlying these conditions. Identifying the genetic changes underlying ASD has gradually led to the recognition that some of these conditions may be parts of a disease spectrum rather than isolated anomalies. The characterization of the underlying genetic abnormalities responsible for glaucoma is the first step toward developing diagnostic and screening tests, which could identify individuals at risk for disease before irreversible optic nerve damage occurs. It is also crucial for genetic counseling and risk stratification of later pregnancies. It also aids prenatal testing by various methods allowing for effective genetic counseling. This review summarizes various ocular and systemic conditions that result in secondary developmental glaucoma and provide an overview of the phenotypes, the diagnosis and principles of management of the various disorders.

Choroidal Hyperreflective Nodules Detected by Infrared Reflectance Images Are a Diagnostic Criterion for Neurofibromatosis Type 1 Patients Excluding Those with High Myopia

Neurofibromatosis type 1 (NF1) is one of the central nervous system’s most common autosomal dominant conditions. The diagnosis is based on the clinical diagnostic criteria and/or a molecularly confirmed mutation in the NF1 gene. This study investigated the possibility of substantiating choroidal nodules as a diagnostic criterion for the disease, including patients affected with and without high myopia. A cross-sectional study was carried out in 60 eyes of 30 adult patients diagnosed with NF1. A total of 30 healthy individuals of equivalent age and sex served as control. The Spectralis HRA+OCT MultiColor (Heidelberg Engineering GmbH, Heidelberg, Germany) evaluated the presence of choroidal abnormalities with near-infrared reflectance imaging. Secondly, the presence of iridian Lisch nodules was evaluated by slit lamp examination. Near-infrared reflectance imaging showed the presence of choroidal hyperreflective nodules in 83% of the patients diagnosed with NF1, while these choroidal abnormalities were not observed in any control subject. The patients diagnosed with NF1 associated with high myopia were the only ones who did not present the characteristic choroidal disorders. Therefore, when excluding patients diagnosed with high myopia, choroidal nodules were more frequent than Lisch nodules in a statistically significant proportion. Hyperreflective nodules detected by near-infrared reflectance imaging are as regular as Lisch nodules or even significantly more frequent when excluding high myope patients. Our observation of the mutual exclusion of choroidal hyperreflective nodules and high myopia in the NF1 patients seems a novel and interesting remark.

Burden Among Caregivers of Pediatric Patients with Neurofibromatosis Type 1 (NF1) and Plexiform Neurofibroma (PN) in the United States: A Cross-Sectional Study

Introduction

Patients with neurofibromatosis type 1 (NF1) may develop plexiform neurofibromas (PNs) that can cause disfigurement, pain, and dysfunction, and may even be life-threatening. Studies have indicated NF1-PN can substantially impact the quality of life (QoL) of pediatric patients. However, research on caregiver burden is scarce.

Methods

Caregivers of pediatric patients ages 2–18 years with NF1-PN in the USA were recruited through the Children’s Tumor Foundation to participate in an online cross-sectional survey (December 2020–January 2021). Caregiver burden was measured using the Zarit Burden Interview (ZBI), and productivity loss from patientcare was measured using the Work Productivity and Activity Impairment questionnaire, adapted for caregiving (WPAI:CG).

Results

Ninety-five caregivers were recruited with a median age of 44.0 years. Most were female (88.4%), white/Caucasian (85.3%), and did not have NF1 or PN (86.3% and 89.5%, respectively). Commonly reported health conditions among caregivers include anxiety (48.4%) and depression (34.7%). On the ZBI (range 0–88; higher = greater burden), mean (SD) scores were 23.0 (13.8) and 12.7% of caregivers reported moderate–severe (scores 41–60) or severe burden (scores 61–88). Fifty-six caregivers were employed and working in the 7 days prior to completing the WPAI:CG. They reported missing an average of 6.9% of their working hours and an average reduction of 17.3% of on-the-job effectiveness, contributing to 22.3% loss in work productivity. Among all 95 caregivers, an average of 17.2% of regular daily activities were impaired.

Conclusions

The burden among caregivers of pediatric patients with NF1-PN is considerable and underscores an unmet need for better disease management.

Clinical and humanistic burden among pediatric patients with neurofibromatosis type 1 and plexiform neurofibroma in the USA

PURPOSE

To assess clinical and humanistic burden among pediatric patients with neurofibromatosis type 1 (NF1) and plexiform neurofibroma (PN) in the USA.

METHODS

NF1-PN patients aged 8-18 years (treatment-naïve or ≤ 1 month of selumetinib treatment) and their caregivers and caregivers of similar patients aged 2-7 years were recruited through the Children's Tumor Foundation to participate in an online cross-sectional survey (December 2020-January 2021). Caregivers provided data on patients' demographic and clinical characteristics and burden of debulking surgeries. Patients and caregivers provided self-reported or proxy responses to health-related quality of life (HRQoL) questions using validated instruments.

RESULTS

Sixty-one patients and 82 caregivers responded to the survey. Median (range) age of patients was 11.5 (3-18) years, and 53.7% were female. Most were treatment-naïve (97.6%), with NF1-PN diagnosis for > 5 years (68.3%). Most patients (59.8%) had > 1 PN and 11.0% reporting > 5 PNs. Common NF1-PN symptoms included pain (64.6%), disfigurement (32.9%), and motor dysfunction (28.0%). Patients and caregiver proxies reported low overall HRQoL and reduced physical, emotional, social, and school functioning. Patients also reported considerable pain severity, interference, daily activity impairments, and movement difficulty. Few patients had received complete resections of their tumors (12.2%). 39.0% reported ≥ 1 debulking surgery, among whom, 15.6% had complications, and debulking surgery-related hospitalizations were common (53.1%).

CONCLUSIONS

The clinical and humanistic burden among pediatric NF1-PN patients is substantial. While debulking surgeries are used for symptom management, they are associated with considerable clinical sequelae. Results highlight a need for improved disease management strategies.

Ocular Neurofibromatosis

A 14-year-old boy presented with a right orbital lid mass, which had slowly grown over the last 4.5 years, as well as some impaired visual acuity in the affected (right) eye. We assessed the patient by taking a detailed history and physical examination. A Snellen chart was used to assess visual acuity, which revealed decreased acuity in the right eye as compared to the left eye. Pupillary reactions, including relative afferent pupillary reflexes, were unremarkable; anterior and posterior chamber assessment was normal including that of the optic disc and macula. Additionally, the intraocular pressure was within acceptable limits. The mass was excised surgically as it had caused significant disfigurement and posed risk to the patient in terms of the possibility for the lesion to increase in severity. It was an approach utilizing a blepharoplasty incision, horizontal wedge resection, and a frontalis sling done under general anesthesia. A biopsy of the mass identified it as a plexiform lesion of the orbit such as that attributed to neurofibromatosis type 1.

Corneal endothelial cells and central corneal thickness in patients with neurofibromatosis type 1

Purpose:

The aim of this study was to evaluate the morphological properties of corneal endothelial cells and central corneal thickness (CCT) in patients with neurofibromatosis type 1 (NF1) and to compare them with age-matched healthy controls.

Methods:

Nineteen NF1 patients and 38 healthy individuals were recruited. All participants underwent complete ophthalmological examination as well as noncontact specular microscopy to measure endothelial cell density (ECD), average cell area (AVG), coefficient of variation of cell area (CV), the percentage of hexagonal cells, and CCT. Eyes with previous ocular trauma, inflammation or surgery, and preexisting corneal and ocular surface diseases were excluded.

Results:

NF1 patients had higher ECD compared to healthy controls of the same age (2764.2 ± 270.4 versus 2570.4 ± 449.2 cells/mm, respectively), although at a borderline level (P = 0.051). Patients with NF1 presented significantly lower CV and AVG when compared to controls (32.9 ± 4.6 versus 37.8 ± 9.5%, P = 0.011 and 364.9 ± 34.4 versus 406.0 ± 107.4 µm, P = 0.038, respectively). The NF1 group had significantly higher hexagonality in comparison with controls (55.7 ± 6.5 versus 50.5 ± 9.9%, P = 0.025). CCT was similar between the two groups (P = 0.955).

Conclusion:

Our results show that corneal endothelium has more favorable morphological characteristics in NF1 patients compared to healthy individuals of the same age.

Case Report: Chemotherapy Indication in a Case of Neurofibromatosis Type 1 Presenting Optic Pathway Glioma: A One-Year Clinical Case Study Using Differential Tractography Approach

Neurofibromatosis type 1 (NF1) is associated with peripheral and central nervous system tumors. It is noteworthy that the regions in which these tumors frequently arise are the optic pathways (OPs) and the brainstem. Thus, we decided to trace the procedure of diffusion Magnetic Resonance Imaging (dMRI) alterations along with Short-Wavelength Automated Perimetry (SWAP) examinations of the OPs after surgery and chemotherapy over 1 year, which enabled us to evaluate chemotherapy's efficacy in an NF1 patient with an OP tumor. In this study, a 25-year-old woman with NF1 and left optic radiation (OR) glioma underwent surgery to remove the glioma. Immunohistochemistry (IHC) revealed a Pilocytic Astrocytoma (PA) WHO grade I. Post-operation chemotherapy done using nine treatment cycles of administering Temozolomide (TMZ) for 5 days every 4 weeks. Applying the region of interest (ROI) differential tractography method and SWAP four times every 3 months allowed us to follow the patient's visual acuity alterations longitudinally. The differential deterministic tractography method and statistical analyses enabled us to discover the white matter (WM) tracts anisotropy alterations over time. Furthermore, statistical analyses on the SWAP results along time illustrated possible alterations in visual acuity. Then, we could compare and associate the findings with the SWAP examinations and patient symptoms longitudinally. Statistical analyses of SWAP tests revealed a significant improvement in visual fields, and longitudinal differential tractography showed myelination and dense axonal packing in the left OR after 1 year of treatment. In this study, we examined an old hypothesis suggesting that chemotherapy is more effective than radiotherapy for NF1 patients with OP gliomas (OPGs) because of the radiation side effects on the visual field, cognition, and cerebrovascular complications. Our longitudinal clinical case study involving dMRI and SWAP on a single NF1-OPG patient showed that chemotherapy did not suppress the OP myelination over time. However, it should be noted that this is a clinical case study, and, therefore, the generalization of results is limited. Future investigations might focus on genetic-based imaging, particularly in more cases. Further, meta-analyses are recommended for giving a proper Field Of View (FOV) to researchers as a subtle clue regarding precision medicine.

Optic Nerve Tortuosity in Neurofibromatosis Type 1: A Rare Case Report

Optic nerve tortuosity is a benign and usually asymptomatic optic nerve abnormality documented on magnetic resonance imaging. This abnormality has rarely been defined in neurofibromatosis type 1 (NF1) cases. In this case report, we present incidental optic nerve tortuosity in a housewife with NF1 without any ocular involvement. Optic nerve tortuosity may occasionally be an incidental finding in patients with NF1. Therefore, clinicians should be aware of this rare coexistence.

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.

Neuro-ophthalmological manifestations of tuberous sclerosis: current perspectives

Tuberous sclerosis complex (TSC) is a complex, multi-system disorder with a well-described underlying genetic etiology. While retinal findings are common in TSC and important in establishing the diagnosis, TSC also has many potential neuro-ophthalmology manifestations. The neuro-ophthalmology manifestations of TSC can have a significant impact on visual function and are sometimes a sign of serious neurological disease. The purpose of this review is to describe the neuro-ophthalmological manifestations of TSC. These manifestations include optic nerve hamartomas, elevated intracranial pressure, cranial nerve palsies, cortical visual impairment, visual field deficits, and ocular toxicity from vigabatrin treatment of infantile spasms. It is important to be aware of potential neuro-ophthalmological manifestations in these patients in order to detect signs of vision- or life-threatening disease and to optimize visual function and quality-of-life.

Use of Optical Coherence Tomography to Detect Retinal Nerve Fiber Loss in Children With Optic Pathway Glioma

Optic pathway glioma (OPG) presents in childhood and can cause significant morbidity and visual loss. Magnetic resonance imaging (MRI) is the current imaging modality of choice for evaluation of OPG progression, but it is a relatively limited resource often requiring sedation in the pediatric age group. Additionally, OPG progression on MRI does not always correlate with clinical progression. As a result, several other modalities for evaluating OPG are being investigated, including optical coherence tomography (OCT), a readily available imaging technique in ophthalmic practice. The purpose of the present study was to examine the association between retinal nerve fiber layer (RNFL) thickness measured using OCT and optic nerve function in children with OPG with and without neurofibromatosis-1 (NF-1). A retrospective chart review was conducted to identify children diagnosed with OPG from 2001 to 2015 at a tertiary pediatric medical center. The correlation between OCT measurements and clinical visual parameters was statistically analyzed. Included were 23 children with imaging-confirmed OPG and spectral domain OCT: 10 with NF-1 (mean age at diagnosis 5.8 years) and 13 without (mean age at diagnosis 5.9 years). The glioma involved the chiasma-hypothalamus in 19 patients, optic nerve in 11, and optic tract in 7; more than one anatomic site was affected in 15. Symptoms were reported in 2 patients with NF-1 and most patients without NF-1. Visual field defects included monocular, bitemporal, nasal, and homonymous hemianopia. Initial mean RNFL was 85.4 μm in the NF-1 group and 65 μm in the non-NF-1 group. Visual acuity deteriorated in 1/10 patients and 5/13 patients, respectively. Repeated OCT showed continued RNFL thinning in 3 patients (5 eyes) in the NF-1 group and in 8 patients (11 eyes) in the non-NF-1 group, often associated with a decrease in optic nerve function. In conclusion, visual function in children with OPG is correlated with repeated OCT measurements and weakly with neuroimaging. Children without NF-1 are usually symptomatic and have a worse clinical outcome. These findings may have important implications when considering initiating, continuing or stopping chemotherapy for OPG. The application of OCT in the assessment of OPG and the correlation of the findings to clinical progression can have a significant impact on OPG patient management.