Recurrence of spinal schwannomas in a patient with neurofibromatosis type 1: a case report.

Introduction and importance: Spinal schwannomas are benign tumors usually attached to peripheral nerves, consisting of a clonal population of Schwann cells. Neurofibromatosis type 1 is an autosomal dominant neurocutaneous disorder that predominantly affects the skin, bone and nervous system. Neurofibromatosis type 1 is a clinically and genetically distinct from neurofibromatosis type 2. This case report highlights the rare association between spinal schwannoma and neurofibromatosis type 1. Case presentation: The patient with a past medical history of spinal schwannoma, operated 1 year back, presented with back pain, weakness of lower limbs and urge incontinence. On examination, she had cutaneous features suggestive of neurofibromatosis type 1 and there was impairment of all sensory modalities below hip region. MRI revealed spinal schwannoma at D9 level for which laminectomy with removal of schwannoma was performed. Clinical discussion: The occurrence and recurrence of spinal schwannoma in neurofibromatosis type 2 is a common finding. But such an association has not been established between spinal schwannoma and neurofibromatosis type 1. In this case, the recurrence of spinal schwannoma has been linked to neurofibromatosis type 1 in the absence of other well-defined etiologies. Conclusion: The occurrence of spinal schwannoma can be genetic or sporadic. The recurrence is usually associated with familial tumor syndrome. The available literature has not established association between neurofibromatosis type 1 and spinal schwannoma, thus, emphasizing the need of more focused studies.

A successful combined spinal-epidural anesthesia for cesarean section in a patient with neurofibromatosis type 1-associated dural ectasia.

BACKGROUND: Dural ectasia is a common manifestation of neurofibromatosis type 1. Although there have been reports of unsuccessful spinal anesthesia due to dual ectasia in Marfan syndrome, reports describing similar unsuccessful spinal anesthesia in neurofibromatosis type 1 are lacking. CASE PRESENTATION: A parturient with neurofibromatosis type 1 was scheduled for a repeat cesarean section. During a previous cesarean section, she had experienced a failed spinal anesthesia, which resulted in a conversion to general anesthesia. Preoperative lumbar magnetic resonance imaging revealed dural ectasia, which was speculated to be the cause of the previous spinal anesthesia failure. Therefore, combined spinal-epidural anesthesia was implemented. Because the block level of spinal anesthesia was insufficient as predicted, supplemental administration of epidural anesthesia successfully provided adequate analgesia for the surgery. CONCLUSIONS: Combined spinal-epidural anesthesia can be useful for the management of cesarean sections in patients with neurofibromatosis type 1-associated dural ectasia.

Investigation of nasal cavity alterations in individuals with neurofibromatosis type 1 using CBCT.

OBJECTIVES: This study aimed to investigate nasal septum deviation (NSD), nasal bone length (NBL), and the morphology of the middle nasal conchae (MNC) and inferior nasal conchae (INC), as well as their correlations. MATERIALS AND METHODS: The sample included 56 cone-beam computed tomography scans divided into two groups: a study group (SG; individuals with NF1; n = 28) and a control group (CG; individuals without NF1; n = 28). NSD, NBL, MNC, and INC classifications were assessed. MNC images were classified as normal, bullous, paradoxical, secondary, and accessory. INC images were classified as normal, lamellar, compact, combined, and bullous. Intra- and interobserver reliability were evaluated. RESULTS: SG had a mean NSD of 11.6° (±4.5°) compared with 9.6° (±3.2°) for the CG, showing moderate deviations with no significant difference between groups. SG had a mean NBL of 22.4 mm (±3.4 mm) compared with 22.1 mm (±3.2 mm) for the CG, with a statistically significant difference. Both groups exhibited normal, bullosa, and accessory MNC classifications. SG INC were normal, lamellar, and combined, whereas CG INC were normal and lamellar. There was a weak correlation between NSD and NBL across groups. CONCLUSION: Individuals with NF1 showed longer NBL. The weak correlation between NSD and NBL suggested multifactorial influences on these variations. These findings advance our understanding of craniofacial development in NF1 and highlight the need for further research into nasal cavity involvement in this complex genetic disorder.

Cold Atmospheric Plasma Induces Growth Arrest and Apoptosis in Neurofibromatosis Type 1-Associated Peripheral Nerve Sheath Tumor Cells.

Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder resulting from mutations in the NF1 gene. Patients harboring these mutations are predisposed to a spectrum of peripheral nerve sheath tumors (PNSTs) originating from Schwann cells, of which malignant peripheral nerve sheath tumors (MPNSTs) are the deadliest, with limited treatment options. Therefore, an unmet need still exists for more effective therapies directed at these aggressive malignancies. Cold atmospheric plasma (CAP) is a reactive oxygen species (ROS) and reactive nitrogen species (RNS) generating ionized gas that has been proposed to be a potential therapeutic modality for cancer. In this study, we sought to determine the effects of CAP on NF1-associated PNSTs. Utilizing established mouse and human cell lines to interrogate the effects of CAP in both in vitro and in vivo settings, we found that NF1-associated PNSTs were highly sensitive to CAP exposure, resulting in cell death. To our knowledge, this is the first application of CAP to NF1-associated PNSTs and provides a unique opportunity to study the complex biology of NF1-associated tumors.

Interferon-Induced Transmembrane Protein 1 (IFITM1) Is Downregulated in Neurofibromatosis Type 1-Associated Malignant Peripheral Nerve Sheath Tumors.

Neurofibromatosis type 1 (NF1), an autosomal dominant genetic disorder, is caused by mutations in the NF1 gene, which encodes the GTPase-activating protein neurofibromin. The pathogenesis of the tumor progression of benign plexiform neurofibromas (PNs) and malignant peripheral nerve sheath tumors (MPNSTs) remain unclear. Here, we found that interferon-induced transmembrane protein 1 (IFITM1) was downregulated in MPNST tissues compared to those in PN tissues from patients with NF1. Overexpression of IFITM1 in NF1-associated MPNST cells resulted in a significant decrease in Ras activation (GTP-Ras) and downstream extracellular regulatory kinase 1/2 (ERK1/2) phosphorylation, whereas downregulation of IFITM1 via treatment with small interfering RNA in normal Schwann cells had the opposite result, indicating that expression levels of IFITM1 are closely associated with tumor progression in NF1. Treatment of MPNST cells with interferon-gamma (IFN-γ) significantly augmented the expression of IFITM1, thereby leading to a decrease in Ras and ERK1/2 activation. Despite the small number of patient samples, these findings may potentially provide a new target for chemotherapy in patients with NF1-associated MPNSTs. In xenograft mice injected with MPNST cells, IFN-γ treatment successfully suppressed tumor progression with increased IFITM1 expression and decreased Ras and ERK1/2 activation in tumor tissues. Collectively, these results suggest that IFITM1 is closely involved in MPNST pathogenesis and that IFN-γ is a good candidate for the therapeutic treatment of MPNSTs in NF1.

Comparing 3D imaging devices for the measurement of cutaneous neurofibromas in patients with Neurofibromatosis Type 1.

BACKGROUND: Cutaneous neurofibromas (cNFs) are a major cause of disfigurement in patients with Neurofibromatosis Type 1 (NF1). However, clinical trials investigating cNF treatments lack standardised outcome measures to objectively evaluate changes in cNF size and appearance. 3D imaging has been proposed as an objective standardised outcome measure however various systems exist with different features that affect useability in clinical settings. The aim of this study was to compare the accuracy, precision, feasibility, reliability and accessibility of three imaging systems. MATERIALS AND METHODS: We compared the Vectra-H1, LifeViz-Micro and Cherry-Imaging systems. A total of 58 cNFs from 13 participants with NF1 were selected for imaging and analysis. The primary endpoint was accuracy as measured by comparison of measurements between imaging systems. Secondary endpoints included reliability between two operators, precision as measured with the average coefficient of variation, feasibility as determined by time to capture and analyse an image and accessibility as determined by cost. RESULTS: There was no significant difference in accuracy between the three devices for length or surface area measurements (p > 0.05), and reliability and precision were similar. Volume measurements demonstrated the most variability compared to other measurements; LifeViz-Micro demonstrated the least measurement variability for surface area and image capture and analysis were fastest with LifeViz-Micro. LifeViz-Micro was better for imaging smaller number of cNFs (1-3), Vectra-H1 better for larger areas and Cherry for uneven surfaces. CONCLUSIONS: All systems demonstrated excellent reliability but possess distinct advantages and limitations. Surface area is the most consistent and reliable parameter for measuring cNF size in clinical trials.

Different de novo mutations in the NF1 gene in a family with neurofibromatosis type 1.

The criteria for clinical diagnosis of neurofibromatosis type 1 (NF1) are not sensitive in young children. Recognition is easier when one of their parents has been diagnosed with this condition, and the causal mutation is known. We present a case of a girl with isolated café-au-lait spots, whose father was diagnosed with NF1. However, both were found to carry different de novo mutations in the NF1 gene. This possibility has significant implications for the diagnostic process and genetic counseling.

Consensus recommendations on management of selumetinib-associated adverse events in pediatric patients with neurofibromatosis type 1 and plexiform neurofibromas.

Background: Selumetinib is the first approved treatment for pediatric patients with neurofibromatosis type 1 (NF1) and symptomatic, inoperable plexiform neurofibromas (PN) in the EU and US, as well as in multiple other countries. Evidence for the management of selumetinib-associated adverse events (AEs) is mostly limited to clinical trials and expanded-access programs. We gathered a panel of European healthcare practitioners with clinical experience prescribing selumetinib and/or managing pediatric patients with NF1-PN to provide recommendations on the prevention and management of AEs. Methods: A modified Delphi approach was used to develop the recommendations among the group of experts. Initial statements were developed from a literature review of current management recommendations and regulatory reports. The panel refined the statements and rated the extent to which they agreed with them in 2 sessions and a follow-up survey. The panel comprised 2 pediatric neuro-oncologists, 1 pediatric oncologist, 1 pediatrician, 1 neuropediatrician, 1 oncologist, 1 neurologist, 2 psychologists, and 1 dermatologist. Results: The experts agreed on the relative frequency and impact of AEs potentially associated with selumetinib. Consensus-level agreement was reached for 36 statements regarding the prevention and management of AEs potentially associated with selumetinib. Experts recommended treatments for AEs based on their experience. Conclusions: The development of a variety of consensus statements indicates expert agreement on best practices for the prevention and management of AEs potentially associated with selumetinib in pediatric patients with NF1-PN. These events are generally manageable and should be considered alongside treatment benefit. Information sharing is warranted as further experience is gained.

Neurofibromatosis type 1 adult surveillance form for Austria.

BACKGROUND: Neurofibromatosis type 1 (NF1) is a rare autosomal dominant tumor predisposition syndrome with a birth prevalence of approximately 1 in 2000-3000 individuals. Management of both benign and malignant tumors arising in individuals with NF1 is demanding and tumors may be difficult to treat. Both standardized and individual surveillance programs are therefore highly important to prevent morbidity and mortality in patients with NF1. METHODS: The guidelines for the clinical management of NF1 recently proposed by the European Reference Network for Genetic Tumor Risk Syndromes provide the cornerstone of the present surveillance form and were discussed through three rounds of voting and a final consensus meeting involving experts from five Austrian and one German clinical NF1 centers for adults and one patient organization representative. Subsequently, 31 items within 4 categories were integrated into the proposed surveillance form for Austria. All recommendations, unless otherwise specified, pertain to primarily asymptomatic patients in routine follow-up. RECOMMENDATIONS: At healthcare transition from pediatric to adult surveillance or the initial visit in adulthood, we suggest a thorough clinical, laboratory and radiological examination to obtain a baseline for future diagnostics. To comply with the general screening recommendations in Austria, we suggest extending the frequency of clinical visits from annual to biennial at 50 years of age. In cases of clinical dynamics, early follow-up is recommended to facilitate early detection of potential complications. Particular emphasis should be placed on preventive patient education.

Effect of Everolimus on Prognosis of Neurofibromatosis Type 1 Lesions: A Systematic Review and Meta Analysis.

PURPOSE: This study addresses the effectiveness of oral everolimus in treating various malignancies associated with Neurofibromatosis Type 1 (NF1). The purpose is to determine whether everolimus reduces lesion size in NF1 patients, considering the controversial findings from previous clinical trials. The scientific hypotheses and questions involve evaluating the impact of everolimus on NF1-associated lesions and understanding the variability in treatment outcomes. METHODS: A systematic review and meta-analysis were conducted following PRISMA and Cochrane Collaboration guidelines. The study included four-phase II, single-arm, nonrandomized trials investigating the effect of oral everolimus on NF1-associated lesion size. The search covered multiple databases, and data extraction involved evaluating studies for inclusion criteria and assessing quality using the Cochrane Collaboration's Risk of Bias in Nonrandomized Studies tool. Statistical analysis utilized Open Meta(Analyst). FINDINGS: The search yielded 388 studies, with 10 selected for full-text review and four included in the final analysis. The quality of the studies ranged from low to moderate. The meta-analysis indicated no observed heterogeneity (I^2 = 0%), and the overall estimate suggested no significant reduction in NF1-associated lesion size with everolimus (P = 0.069). IMPLICATIONS: The findings reveal a varied and inconsistent picture of everolimus efficacy in NF1 treatment. The study highlights the need for personalized approaches, considering individual genetic and clinical differences. The limitations, including small sample sizes and nonrandomized trials, call for larger, more standardized research efforts. The study emphasizes ongoing trials and the importance of future research in understanding predictors of everolimus response and optimizing treatment strategies for NF1 patients. CONCLUSION: While everolimus shows promise in reducing lesion size in a subset of NF1 patients, the study cannot draw conclusive results due to limitations in the included studies. Ongoing, adequately powered trials are crucial for advancing the evidence base and informing the potential role of everolimus in NF1 treatment. OTHERS: There was no funding for this review and no conflicts of interest.

Long-term distress throughout one's life: health-related quality of life, economic and caregiver burden of patients with neurofibromatosis type 1 in China.

Introduction: Neurofibromatosis type 1 (NF1) is a rare genetic disorder, with lack of evidence of disease burden in China. We aimed to describe the economic burden, health-related quality of life (HRQL), and caregiver burden of NF1 patients in China. Methods: We conducted an online cross-sectional survey employing the China Cloud Platform for Rare Diseases, with 223 caregivers of NF1 pediatric patients (patients under 18), and 226 adult patients. Economic burden was estimated using direct and indirect costs related to NF1 in 2021, and the Work Productivity and Activity Impairment Questionnaire: General Health V2.0 (WPAI-GH). HRQL measures included EQ-5D-Y proxy version and PedsQL™ 4.0 Generic Core Scales (PedsQL GCS) proxy version for pediatric patients, and EQ-5D-5L and PedsQL™ 3.0 Neurofibromatosis Module (PedsQL NFM) for adult patients. Caregiver burden was estimated by Zarit Burden Interview (ZBI). Results: For pediatric patients, the average direct cost in 2021 was CNY 33,614 (USD 4,879), and employed caregivers' annual productivity loss was 81 days. EQ-5D-Y utility was 0.880 ± 0.13 and VAS score was 75.38 ± 20.67, with 52.6% patients reporting having problems in "pain/discomfort" and 42.9% in "anxiety/depression." PedsQL GCS total score was 68.47 ± 19.42. ZBI score demonstrated that 39.5% of caregivers had moderate-to-severe or severe burden. For adult patients, average direct cost in 2021 was CNY 24,531 (USD 3,560). Patients in employment reported an absenteeism of 8.5% and presenteeism of 21.6% according to the results of WPAI-GH. EQ-5D-5L utility was 0.843 ± 0.17 and VAS score was 72.32 ± 23.49, with more than half of patients reporting having problems in "pain/discomfort" and "anxiety/depression" dimensions. PedsQL NFM total score was 68.40 ± 15.57. Conclusion: Both pediatric and adult NF1 patients in China had a wide-ranging economic burden and low HRQL, especially in the psychological dimension. Caregivers for NF1 pediatric patients experienced considerable caregiver burden. More attention and support from policymakers and stakeholders are required to relieve NF1 patients' and caregivers' distress.

Diagnosis and management of neurofibromatosis type 1 in Arabian Gulf Cooperation Council Region: challenges and recommendations.

Neurofibromatosis type 1 (NF1) is a complex multisystem genetic disorder that requires long-term, age-specific monitoring and multidisciplinary care. NF1 symptom burden can significantly affect the quality of life and impose a substantial economic burden on patients and their families. The approval and widespread availability of mitogen-activated protein kinase (MEK) inhibitors such as selumetinib for NF1-related plexiform neurofibromas have revolutionized the standard of care for patients with NF1, however their effective utilization hinges on early recognition of NF1. We present a consensus manuscript describing the challenges observed in the Arabian Gulf Cooperation Council (GCC) for diagnosing and managing NF1. Experts from the GCC also present recommendations for the early recognition and management of NF1 and its complications. A referral pathway that can play a crucial role in helping primary healthcare providers refer their patients to experts is also proposed. Increasing the availability and accessibility of genetic testing at an affordable cost and optimizing personalized NF1 care are essential for NF1 management. Developing regional guidelines for NF1 management and establishing NF1 centers of excellence may facilitate better care and outcomes for patients with NF1 in the GCC region.

LZTR1 loss-of-function variants associated with café au lait macules with or without freckling.

Pathogenic variants in the leucine zipper-like transcriptional regulator 1 gene (LZTR1) have been identified in schwannomatosis and Noonan syndrome. Here, we expand the phenotype spectrum of LZTR1 variants. We identified four loss-of-function heterozygous LZTR1 variants in five children with multiple café au lait macules and one adult with multiple café au lait macules and axillar freckling, by applying gene panel analysis in four families. The three LZTR1 variants, namely, c.184del/p.Glu62Serfs*39, c.1927C < T/p.Gln643*, and c.857_858delinsT/p.Gly286Valfs*65, were novel, whereas the variant c.1018C > T/ p.Arg340* had been previously reported in a patient with schwannomatosis. Similar to what is known from other LZTR1-associated conditions, penetrance of the skin manifestations was reduced in two carriers of the familial variants. Our study expands the LZTR1 phenotype to the presence of isolated café au lait macules with or without freckling. Thus, variants in the LZTR1 gene should be considered in patients with multiple café au lait macules.

Traumatic arteriovenous fistula of the superficial temporal artery caused by massive subcutaneous hematoma prompting surgical removal and endovascular treatment in a patient with neurofibromatosis type 1.

Background: Neurofibromatosis type 1 (NF-1) is often characterized by vascular disorders related to vessel vulnerability that can lead to unfavorable outcomes. Here, we describe a case of NF-1 complicated with a massive subcutaneous hematoma posing a risk of visual impairment for which rapid decompression and a subsequent less invasive approach result in a favorable outcome. Case Description: A 40-year-old woman with NF-1 presented with a massive left subcutaneous temporal hematoma following a mild head contusion. Four days after hospitalization, the hematoma increased in size and severely compressed the left eye, prompting immediate hematoma removal to preserve visual function. Immediately after the hematoma removal, a superficial temporal arteriovenous fistula was found on the digital subtraction angiography and embolized by the endovascular procedure. Her visual acuity was preserved, and no bleeding recurrence was observed throughout the follow-up. Conclusion: Surgical hematoma removal followed by endovascular treatment was effective in preserving visual function. Since vessel fragility is characteristic of patients with NF-1, it should be kept in mind that vascular complications may lead to serious clinical outcomes. In certain NF-1 cases, less invasive treatments for vascular abnormalities may be preferable.

Association of sociodemographic and clinical factors with the quality of life of Brazilian individuals with Neurofibromatosis type 1: a cross-sectional study

Abstract Background Neurofibromatosis type 1 (NF1) is a rare genetic disorder with a wide range of clinical manifestations, notably neurocutaneous features, that can lead to emotional and physical consequences. Objectives This study assessed the influence of sociodemographic factors and clinical features of the disease on the quality of life of Brazilian individuals with NF1. Methods This is a descriptive cross-sectional study. Data were collected from 101 individuals with NF1 using the Brazilian version of the Impact of NF1 on Quality of Life Questionnaire (INF1-QoL), a form with information on sociodemographic characteristics, and an NF1 visibility self-evaluation scale. The relationship between variables was evaluated through statistical testing, and the significance level was defined as 0.05. Results The study included 101 adults with NF1 aged 18 to 59 years, with a mean age of 35.54 years (±9.63) and a female predominance (n = 84, 83.17%). The mean total INF1-QoL score was 10.62 (±5.63), with a median of 10, minimum value of 0, and maximum of 31 points. Two characteristics of the participants were significantly associated with the quality of life: educational level (p = 0.003) and familial history of NF1 (p = 0.019). There was a statistically significant correlation between the INF1-QoL score and the degree of disease visibility (rho = 0.218; p = 0.028). Study limitations Cross-sectional study, conducted with a convenience sample and using self-reported measures. Conclusions The findings support the significant impact of NF1 on quality of life. The authors recommend multidisciplinary follow-up for patients, with adherence to anticipatory clinical care measures, adequate pain control, psychological assistance, and genetic counseling.

Pathological findings in enucleated eyes of patients with neurofibromatosis type 1: report of a case with 15-year follow-up and review of 14 patients in the literature.

BACKGROUNDS: Iris nodules are frequently noted as clinical manifestations of neurofibromatosis type 1 but the other intraocular manifestations are rare. The purpose of this study is to present a patient with a phthisic eye who underwent enucleation for a cosmetic reason after 15-year follow-up and also to review 14 patients with enucleation described in the literature. CASE PRESENTATION: A 17-year-old man with neurofibromatosis type 1 from infancy underwent the enucleation of phthisic left eye and also had the resection of eyelid subcutaneous mass lesions on the left side for a cosmetic reason. He had undergone four-time preceding surgeries for eyelid and orbital mass reduction on the left side in childhood and had developed total retinal detachment 10 years previously. Pathologically, the enucleated eye showed massive retinal gliosis positive for both S-100 and glial fibrillary acidic protein (GFAP) in the area with involvement of the detached retinal neuronal layer, together with a more fibrotic lesion along the choroid which were, in contrast, negative for both S-100 and GFAP. The choroid, ciliary body, and iris did not show apparent neurofibroma while episcleral neurofibroma was present. LITERATURE REVIEW: In review of enucleated eyes of 14 patients in the literature, buphthalmic eyes with early-onset glaucoma on the unilateral side was clinically diagnosed in 9 patients who frequently showed varying extent of hemifacial neurofibromatosis which involved the eyelid and orbit on the same side. Pathologically, neurofibromas in varying extent were found in the choroid of 12 patients. One patient showed choroidal malignant melanoma on the left side and fusiform enlargement of the optic nerve on the right side suspected of optic nerve glioma. The phthisic eye in another patient showed massive retinal gliosis similar to the present patient. CONCLUSIONS: In summary of the 15 patients with neurofibromatosis type 1, including the present patient, buphthalmic or phthisic eyes with no vision were enucleated for cosmetic reasons and showed choroidal neurofibroma in most patients and massive retinal gliosis in two patients including the present patient.

Heterozygosity for loss-of-function variants in LZTR1 is associated with isolated multiple café-au-lait macules.

PURPOSE: Pathogenic LZTR1 variants cause schwannomatosis and dominant/recessive Noonan syndrome (NS). We aim to establish an association between heterozygous loss-of-function LZTR1 alleles and isolated multiple café-au-lait macules (CaLMs). METHODS: A total of 849 unrelated participants with multiple CaLMs, lacking pathogenic/likely pathogenic NF1 and SPRED1 variants, underwent RASopathy gene panel sequencing. Data on 125 individuals with heterozygous LZTR1 variants were collected for characterizing their clinical features and the associated molecular spectrum. In vitro functional assessment was performed on a representative panel of missense variants and small in-frame deletions. RESULTS: Analysis revealed heterozygous LZTR1 variants in 6.0% (51/849) of participants, exceeding the general population prevalence. LZTR1-related CaLMs varied in number, displayed sharp or irregular borders, and were generally isolated but occasionally associated with features recurring in RASopathies. In 2 families, CaLMs and schwannomas co-occurred. The molecular spectrum mainly consisted of truncating variants, indicating loss-of-function. These variants substantially overlapped with those occurring in schwannomatosis and recessive NS. Functional characterization showed accelerated protein degradation or mislocalization, and failure to downregulate mitogen-activated protein kinase signaling. CONCLUSION: Our findings expand the phenotypic variability associated with LZTR1 variants, which, in addition to conferring susceptibility to schwannomatosis and causing dominant and recessive NS, occur in individuals with isolated multiple CaLMs.

Inhibition of autophagy as a novel treatment for neurofibromatosis type 1 tumors.

Neurofibromatosis type 1 (NF1) is a genetic disorder caused by mutation of the NF1 gene that is associated with various symptoms, including the formation of benign tumors, called neurofibromas, within nerves. Drug treatments are currently limited. The mitogen-activated protein kinase kinase (MEK) inhibitor selumetinib is used for a subset of plexiform neurofibromas (PNs) but is not always effective and can cause side effects. Therefore, there is a clear need to discover new drugs to target NF1-deficient tumor cells. Using a Drosophila cell model of NF1, we performed synthetic lethal screens to identify novel drug targets. We identified 54 gene candidates, which were validated with variable dose analysis as a secondary screen. Pathways associated with five candidates could be targeted using existing drugs. Among these, chloroquine (CQ) and bafilomycin A1, known to target the autophagy pathway, showed the greatest potential for selectively killing NF1-deficient Drosophila cells. When further investigating autophagy-related genes, we found that 14 out of 30 genes tested had a synthetic lethal interaction with NF1. These 14 genes are involved in multiple aspects of the autophagy pathway and can be targeted with additional drugs that mediate the autophagy pathway, although CQ was the most effective. The lethal effect of autophagy inhibitors was conserved in a panel of human NF1-deficient Schwann cell lines, highlighting their translational potential. The effect of CQ was also conserved in a Drosophila NF1 in vivo model and in a xenografted NF1-deficient tumor cell line grown in mice, with CQ treatment resulting in a more significant reduction in tumor growth than selumetinib treatment. Furthermore, combined treatment with CQ and selumetinib resulted in a further reduction in NF1-deficient cell viability. In conclusion, NF1-deficient cells are vulnerable to disruption of the autophagy pathway. This pathway represents a promising target for the treatment of NF1-associated tumors, and we identified CQ as a candidate drug for the treatment of NF1 tumors.

Multiparametric whole-body MRI of patients with neurofibromatosis type I: spectrum of imaging findings.

Neurofibromatosis (NF) type I is a neuroectodermal and mesodermal dysplasia caused by a mutation of the neurofibromin tumor suppressor gene. Phenotypic features of NF1 vary, and patients develop benign peripheral nerve sheath tumors and malignant neoplasms, such as malignant peripheral nerve sheath tumor, malignant melanoma, and astrocytoma. Multiparametric whole-body MR imaging (WBMRI) plays a critical role in disease surveillance. Multiparametric MRI, typically used in prostate imaging, is a general term for a technique that includes multiple sequences, i.e. anatomic, diffusion, and Dixon-based pre- and post-contrast imaging. This article discusses the value of multiparametric WBMRI and illustrates the spectrum of whole-body lesions of NF1 in a single imaging setting. Examples of lesions include those in the skin (tumors and axillary freckling), soft tissues (benign and malignant peripheral nerve sheath tumors, visceral plexiform, and diffuse lesions), bone and joints (nutrient nerve lesions, non-ossifying fibromas, intra-articular neurofibroma, etc.), spine (acute-angled scoliosis, dural ectasia, intraspinal tumors, etc.), and brain/skull (optic nerve glioma, choroid plexus xanthogranuloma, sphenoid wing dysplasia, cerebral hamartomas, etc.). After reading this article, the reader will gain knowledge of the variety of lesions encountered with NF1 and their WBMRI appearances. Timely identification of such lesions can aid in accurate diagnosis and appropriate patient management.

Rapid postradiation malignant transformation of a pilocytic astrocytoma in an adult with neurofibromatosis type 1: illustrative case.

BACKGROUND: Juvenile pilocytic astrocytoma (JPA) is the most common primary brain tumor of childhood and is rarely seen in adults. Neurofibromatosis type 1 (NF1), a common tumor predisposition syndrome, demonstrates a strong association with low-grade gliomas, most notably pilocytic astrocytoma, which are relatively indolent. Unlike its juvenile counterpart, reports of adult pilocytic astrocytoma (APA) vary widely in terms of disease progression from benign to much more malignant courses. Moreover, current studies discussing APA report different treatment approaches and outcomes (e.g., malignant transformation of JPA and APA with or without radiation), as little is known regarding the management of recurrent tumors and how adjuvant therapies may alter disease progression. OBSERVATIONS: The authors report the unique case of an adult male with NF1 and APA who underwent rapid malignant conversion after intensity-modulated radiation therapy. LESSONS: The authors demonstrate that caution should be taken in utilizing radiotherapy instead of resection in cases of APA and NF1, with close monitoring for posttreatment recurrence. https://thejns.org/doi/10.3171/CASE24241.