Robust surgical approach for cutaneous neurofibroma in neurofibromatosis type 1

Cutaneous Neurofibromas and Quality of Life in Adults With Neurofibromatosis Type 1

Importance

There is a burgeoning interest in therapeutic development for cutaneous neurofibromas (cNFs), a major cause of morbidity in persons with neurofibromatosis type 1 (NF1). To determine meaningful clinical trial outcomes, deeper understanding is needed regarding how cNFs are associated with quality of life (QoL). However, this understanding has been hampered by challenges in recruiting participants with this rare genetic disease.

Objective

To develop a large, crowdsourced validated registry of persons with NF1 and determine the association of specific cNF features with QoL, pain, and itch.

Design, Setting, and Participants

From May 2021 to December 2023, a decentralized platform was developed and recruited persons 40 years or older with NF1 and at least 1 cNF from 49 states and 12 countries, who provided clinical survey data, detailed photographs, and genetic sequencing data. Photographs from 583 participants were scored on 12 features of cNFs, including general severity, number, size, facial severity, color, and subtypes.

Exposure

cNF features derived from participant-supplied photographs.

Main Outcomes and Measures

Total Skindex scores and subdomain scores (symptoms, emotion, function, pain, and itch).

Results

Of 583 participants, 384 (65.9%) were female, and the mean (range) age was 51.7 (40.0-83.0) years. Female sex, general severity, number, size, and facial severity of cNFs were negatively associated with QoL, as demonstrated by increased total Skindex scores. QoL had the largest association with the number of cNFs and presence of facial cNFs. Increasing number of cNFs was associated with worse QoL, and even individuals with a low cNF burden (<10 total cNFs) experienced a decrease in QoL.

Conclusions and Relevance

The results of this study suggest that reducing cNF number, particularly on the face, may be associated with improved QoL in individuals with NF1. In addition, early intervention before the development of numerous tumors may lead to the highest benefit in QoL. These data potentially provide insight into which individuals and cNF tumors may benefit most from therapy and highlights the utility of a completely decentralized, photograph-validated and age-controlled study for rare genetic disease. This cohort will allow analysis of disease and tumor heterogeneity after full phenotypic expression is achieved in NF1 and potentially serves as an example in its design for other rare diseases that struggle from poor recruitment.

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.

Living in my own skin: dermatological concerns and gender-affirming care as a trans person with neurofibromatosis type 1

We provide patient and clinician perspectives on the dermatological outcomes of patients with neurofibromatosis type 1 (NF1) seeking gender-affirming hormone therapy. This perspectives article speaks to the psychosocial challenges that patients with NF1 may face due to the visible signs and symptoms of their disease. The theoretical role that hormones may play in the development of cutaneous neurofibromas is also addressed.

Noninvasive treatment of cutaneous neurofibromas (cNFs): Results of a randomized prospective, direct comparison of four methods

BACKGROUND

People with Neurofibromatosis Type 1 (NF1) suffer disfigurement and pain when hundreds to thousands of cutaneous neurofibromas (cNFs) appear and grow throughout life. Surgical removal of cNFs under anesthesia is the only standard therapy, leaving surgical scars.

OBJECTIVE

Effective, minimally-invasive, safe, rapid, tolerable treatment(s) of small cNFs that may prevent tumor progression.

METHODS

Safety, tolerability, and efficacy of 4 different treatments were compared in 309, 2-4 mm cNFs across 19 adults with Fitzpatrick skin types (FST) I-IV: radiofrequency (RF) needle coagulation, 755 nm alexandrite laser with suction, 980 nm diode laser, and intratumoral injection of 10 mg/mL deoxycholate. Regional pain, clinical responses, tumor height and volume (by 3D photography) were assessed before, 3 and 6 months post-treatment. Biopsies were obtained electively at 3 months.

RESULTS

There was no scarring or adverse events > grade 2. Each modality significantly (P < .05) reduced or cleared cNFs, with large variation between tumors and participants. Alexandrite laser and deoxycholate were fast and least painful; 980 nm laser was most painful. Growth of cNFs was not stimulated by treatment(s) based on height and volume values at 3 and 6 months compared to baseline.

LIMITATIONS

Intervention was a single treatment session; dosimetry has not been optimized.

CONCLUSIONS

Small cNFs can be rapidly and safely treated without surgery.

Altered actin dynamics is possibly implicated in the inhibition of mechanical stimulation-induced dermal fibroblast differentiation into myofibroblasts

The formation of hypertrophic scars and keloids is strongly associated with mechanical stimulation, and myofibroblasts are known to play a major role in abnormal scar formation. Wounds in patients with neurofibromatosis type 1 (NF1) become inconspicuous and lack the tendency to form abnormal scars. We hypothesized that there would be a unique response to mechanical stimulation and subsequent scar formation in NF1. To test this hypothesis, we investigated the molecular mechanisms of differentiation into myofibroblasts in NF1-derived fibroblasts and neurofibromin-depleted fibroblasts and examined actin dynamics, which is involved in fibroblast differentiation, with a focus on the pathway linking LIMK2/cofilin to actin dynamics. In normal fibroblasts, expression of α-smooth muscle actin (α-SMA), a marker of myofibroblasts, significantly increased after mechanical stimulation, whereas in NF1-derived and neurofibromin-depleted fibroblasts, α-SMA expression did not change. Phosphorylation of cofilin and subsequent actin polymerization did not increase in NF1-derived and neurofibromin-depleted fibroblasts after mechanical stimulation. Finally, in normal fibroblasts treated with Jasplakinolide, an actin stabilizer, α-SMA expression did not change after mechanical stimulation. Therefore, when neurofibromin was dysfunctional or depleted, subsequent actin polymerization did not occur in response to mechanical stimulation, which may have led to the unchanged expression of α-SMA. We believe this molecular pathway can be a potential therapeutic target for the treatment of abnormal scars.

Cutaneous Neurofibroma Heterogeneity: Factors that Influence Tumor Burden in Neurofibromatosis Type 1

Neurofibromatosis type 1 is one of the most common genetic disorders of the nervous system and predisposes patients to develop benign and malignant tumors. Cutaneous neurofibromas (cNFs) are NF1-associated benign tumors that affect nearly 100% of patients with NF1. cNFs dramatically reduce patients' QOL owing to their unaesthetic appearance, physical discomfort, and corresponding psychological burden. There is currently no effective drug therapy option, and treatment is restricted to surgical removal. One of the greatest hurdles for cNF management is the variability of clinical expressivity in NF1, resulting in intrapatient and interpatient cNF tumor burden heterogeneity, that is, the variability in the presentation and evolution of these tumors. There is growing evidence that a wide array of factors are involved in the regulation of cNF heterogeneity. Understanding the mechanisms underlying this heterogeneity of cNF at the molecular, cellular, and environmental levels can facilitate the development of innovative and personalized treatment regimens.

Dermatologic Manifestations of Neurofibromatosis Type 1 and Emerging Treatments

Neurofibromatosis type 1 (NF1) is an autosomal dominant tumor predisposition syndrome that increases one's risk for both benign and malignant tumors. NF1 affects every organ in the body, but the most distinctive symptoms that are often the most bothersome to patients are the cutaneous manifestations, which can be unsightly, cause pain or pruritus, and have limited therapeutic options. In an effort to increase awareness of lesser-known dermatologic associations and to promote multidisciplinary care, we conducted a narrative review to shed light on dermatologic associations of NF1 as well as emerging treatment options. Topics covered include cutaneous neurofibromas, plexiform neurofibromas, diffuse neurofibromas, distinct nodular lesions, malignant peripheral nerve sheath tumors, glomus tumors, juvenile xanthogranulomas, skin cancer, and cutaneous T-cell lymphoma.

Neurofibromatosis type 1 system-based manifestations and treatments: a review

INTRODUCTION

Neurofibromatosis type 1 (NF1) is a genetic disorder caused by a mutation in the NF1 gene. This disease presents with various system-based manifestations, including cardiac, musculoskeletal, and neuronal issues, which have been well-studied in previous research and have prompted the development of current and emerging treatments. These treatments, mainly medications targeting specific manifestations of NF1, aim to mitigate the negative impacts of the disease on patients' lives. NF1 is associated with an increased risk of malignancy and a significant decrease in life expectancy. In this paper, we review the current and emerging treatments for NF1 in relation to its system-based manifestations.

METHODS

We conducted an extensive literature search using specific keywords through databases such as PubMed, Scopus, and Cochrane. The articles we found were compiled and subjected to strict inclusion and exclusion criteria.

RESULTS

Pharmacological advances have led to the development of products that hold promise as future treatments for NF1. Given the diverse manifestations that can affect multiple organ systems in patients with NF1, it is important to consider a variety of treatment options to achieve optimal results. However, one of the major challenges in diagnosing and treating NF1 is that patients present asymptomatically, making it necessary to rely on clinical features for diagnosis.

CONCLUSION

In conclusion, NF1 is a complex disease with varying manifestations and a growing field of pharmacologic treatments. The information presented in this article synthesizes current knowledge and available therapies for NF1.

[Cosmetic and functional results after resection of cutaneous neurofibroma in neurofibromatosis type 1 : Operation of neurofibroma improves quality of life while having moderate complications]

BACKGROUND

Neurofibromatosis type 1, also known as Recklinghausen's disease, is a neurocutaneous tumor syndrome that is genetically determined and is associated with infestation of the integument with neurofibromas (nerve sheath tumors). The occurrence of neurofibromas can be very stressful for patients and often contributes to a reduced quality of life for patients, especially if externally visible body parts are affected. The aim of this study is to show to what extent the resection of cutaneous neurofibromas can improve patients' quality of life.

MATERIALS AND METHODS

For this study, we conducted a retrospective data collection via questionnaire on the quality of life before and after the surgical removal of cutaneous neurofibromas at the Department of Dermatology, University Hospital of Tübingen. An adapted dermatological quality of life index and a postoperative questionnaire on patient satisfaction were used. In addition, patient data were taken from doctor's notes, surgical reports, and outpatient documentation. A total of 30 patients with neurofibromatosis type 1 who underwent inpatient or outpatient surgery for cutaneous neurofibromas at the Tübingen dermatology hospital between 2016 and 2020 were surveyed. The survey results were statistically analyzed and represented as absolute and relative frequencies.

RESULTS

Our study indicates an improved quality of life after surgery for cutaneous neurofibromas, especially regarding limitations in everyday life, self-consciousness, the choice of clothing, and leisure activities. The majority of our patients showed no new occurrence of neurofibromas in the surgical area and postoperative bleeding or wound infections were rare.

CONCLUSION

In relation to the high level of satisfaction with the surgical and cosmetic results and also the positive influence on quality of life, our study indicates a favorable risk-benefit ratio for the resection of cutaneous neurofibromas in neurofibromatosis I.

Characterization of health concerns in people with neurofibromatosis type 1

BACKGROUND

Neurofibromatosis 1 (NF1) is a common cancer predisposition syndrome. Affected individuals require lifelong surveillance and often suffer progressive disfigurement due to cutaneous neurofibromas. The aim of this research was to characterize health concerns and quality of life (QOL) in a population cohort.

METHODS

An online survey was completed by 68 adults and 32 parents of children with NF1, and 60 controls. The survey included the Skindex-29 QOL scale, 5D-itch scale, and additional health questions.

RESULTS

Frequency of itch was high in children (50%) and adults (69%), with most expressing interest in treatment for itch. The presence of itch and increased visibility of NF1 were predictors of poorer QoL. Many adults (53%) and parents (44%) desired access to treatment to improve cosmetic appearance. Muscle weakness/tiredness was also prevalent amongst (60-70%) adults and children with NF1. Two-thirds of adults with NF1 reported limited awareness of NF1 services and poor knowledge of surveillance, particularly breast screening in young women.

CONCLUSION

This study highlights the impact of NF1-related itch and visibility in adults and children with a need for cosmetic and itch treatment. The findings emphasize a need for strategies to promote awareness, and access to management and treatment of NF1 in adults.

The Number of Surgical Interventions and Specialists Involved in the Management of Patients with Neurofibromatosis Type I: A 25-Year Analysis

Objective: In this study, we aim to present a single institution’s 25-year experience of employing a comprehensive multidisciplinary team-based surgical approach for treating patients with NF-1. Summary Background Data: All patients (n = 106) with a confirmed diagnosis of NF-1 who were treated using a multidisciplinary surgical treatment algorithm at Chang Gung Memorial Hospital between 1994 and 2019 were retrospectively enrolled. Patients were categorized into groups according to the anatomy involved (craniofacial and noncraniofacial groups) and the type of clinical presentation (plexiform and cutaneous neurofibromas groups) for comparative analysis. Methods: The number of surgical interventions and number of specialists involved in surgical care were assessed. Results: Most of the patients exhibited craniofacial involvement (69.8%) and a plexiform type of NF-1 (58.5%), as confirmed through histology. A total of 332 surgical interventions (3.1 ± 3.1 procedures per patient) were performed. The number of specialists involved in surgical care of the included patients was 11 (1.6 ± 0.8 specialists per patient). Most of the patients (62.3%) underwent two or more surgical interventions, and 40.6% of the patients received treatment from two or more specialists. No significant differences were observed between the craniofacial and noncraniofacial groups in terms of the average number of surgical interventions (3.3 ± 3.2 vs. 2.7 ± 2.7, respectively) and number of specialists involved (1.7 ± 0.9 vs. 1.4 ± 0.6). Patients with plexiform craniofacial involvement underwent a significantly higher average number of surgical interventions (4.3 ± 3.6 vs. 1.6 ± 1.1; p < 0.001) and received treatment by more specialists (1.9 ± 0.9 vs. 1.2 ± 0.5; p < 0.001) compared with those having cutaneous craniofacial involvement. Conclusions: In light of the potential benefits of employing the multidisciplinary team-based surgical approach demonstrated in this study, such an approach should be adopted to provide comprehensive individualized care to patients with NF-1.

Insights into the Pathogenesis of NF1-Associated Neoplasms

Neurofibromatosis type 1 (NF1) is one of the most common neurocutaneous genetic disorders, presenting with different cutaneous features such as café-au-lait macules, intertriginous skin freckling, and neurofibromas. Although most of the disease manifestations are benign, patients are at risk for a variety of malignancies, including malignant transformation of plexiform neurofibromas. Numerous studies have investigated the mechanisms by which these characteristic neurofibromas develop, with progress made toward unraveling the various players involved in their complex pathogenesis. In this review, we summarize the current understanding of the cells that give rise to NF1 neoplasms as well as the molecular mechanisms and cellular changes that confer tumorigenic potential. We also discuss the role of the tumor microenvironment and the key aspects of its various cell types that contribute to NF1-associated tumorigenesis. An increased understanding of these intrinsic and extrinsic components is critical for developing novel therapeutic approaches for affected patients.

Humanized neurofibroma model from induced pluripotent stem cells delineates tumor pathogenesis and developmental origins

Neurofibromatosis type 1 (NF1) is a common tumor predisposition syndrome caused by NF1 gene mutation, in which affected patients develop Schwann cell lineage peripheral nerve sheath tumors (neurofibromas). To investigate human neurofibroma pathogenesis, we differentiated a series of isogenic, patient-specific NF1-mutant human induced pluripotent stem cells (hiPSCs) into Schwannian lineage cells (SLCs). We found that, although WT and heterozygous NF1-mutant hiPSCs-SLCs did not form tumors following mouse sciatic nerve implantation, NF1-null SLCs formed bona fide neurofibromas with high levels of SOX10 expression. To confirm that SOX10+ SLCs contained the cells of origin for neurofibromas, both Nf1 alleles were inactivated in mouse Sox10+ cells, leading to classic nodular cutaneous and plexiform neurofibroma formation that completely recapitulated their human counterparts. Moreover, we discovered that NF1 loss impaired Schwann cell differentiation by inducing a persistent stem-like state to expand the pool of progenitors required to initiate tumor formation, indicating that, in addition to regulating MAPK-mediated cell growth, NF1 loss also altered Schwann cell differentiation to promote neurofibroma development. Taken together, we established a complementary humanized neurofibroma explant and, to our knowledge, first-in-kind genetically engineered nodular cutaneous neurofibroma mouse models that delineate neurofibroma pathogenesis amenable to future therapeutic target discovery and evaluation.

Human cutaneous neurofibroma matrisome revealed by single-cell RNA sequencing

Neurofibromatosis Type I (NF1) is a neurocutaneous genetic syndrome characterized by a wide spectrum of clinical presentations, including benign peripheral nerve sheath tumor called neurofibroma. These tumors originate from the Schwann cell lineage but other cell types as well as extracellular matrix (ECM) in the neurofibroma microenvironment constitute the majority of the tumor mass. In fact, collagen accounts for up to 50% of the neurofibroma's dry weight. Although the presence of collagens in neurofibroma is indisputable, the exact repertoire of ECM genes and ECM-associated genes (i.e. the matrisome) and their functions are unknown. Here, transcriptome profiling by single-cell RNA sequencing reveals the matrisome of human cutaneous neurofibroma (cNF). We discovered that classic pro-fibrogenic collagen I myofibroblasts are rare in neurofibroma. In contrast, collagen VI, a pro-tumorigenic ECM, is abundant and mainly secreted by neurofibroma fibroblasts. This study also identified potential cell type-specific markers to further elucidate the biology of the cNF microenvironment.

Understanding the Biological Activities of Vitamin D in Type 1 Neurofibromatosis: New Insights into Disease Pathogenesis and Therapeutic Design

Vitamin D is a fat-soluble steroid hormone playing a pivotal role in calcium and phosphate homeostasis as well as in bone health. Vitamin D levels are not exclusively dependent on food intake. Indeed, the endogenous production-occurring in the skin and dependent on sun exposure-contributes to the majority amount of vitamin D present in the body. Since vitamin D receptors (VDRs) are ubiquitous and drive the expression of hundreds of genes, the interest in vitamin D has tremendously grown and its role in different diseases has been extensively studied. Several investigations indicated that vitamin D action extends far beyond bone health and calcium metabolism, showing broad effects on a variety of critical illnesses, including cancer, infections, cardiovascular and autoimmune diseases. Epidemiological studies indicated that low circulating vitamin D levels inversely correlate with cutaneous manifestations and bone abnormalities, clinical hallmarks of neurofibromatosis type 1 (NF1). NF1 is an autosomal dominant tumour predisposition syndrome causing significant pain and morbidity, for which limited treatment options are available. In this context, vitamin D or its analogues have been used to treat both skin and bone lesions in NF1 patients, alone or combined with other therapeutic agents. Here we provide an overview of vitamin D, its characteristic nutritional properties relevant for health benefits and its role in NF1 disorder. We focus on preclinical and clinical studies that demonstrated the clinical correlation between vitamin D status and NF1 disease, thus providing important insights into disease pathogenesis and new opportunities for targeted therapy.

New insights into the neurofibroma tumor cells of origin

Neurofibromatosis type I (NF1) is a debilitating inherited tumor syndrome affecting around 1 in 3000 people. Patients present with a variety of tumors caused by biallelic loss of the tumor suppressor neurofibromin (NF1), a negative regulator of Ras signaling. While the mechanism of tumor formation is similar in the majority of NF1 cases, the clinical spectrum of tumors can vary depending on spatiotemporal loss of heterozygosity of NF1 in cells derived from the neural crest during development. The hallmark lesions that give NF1 its namesake are neurofibromas, which are benign Schwann cell tumors composed of nervous and fibrous tissue. Neurofibromas can be found in the skin (cutaneous neurofibroma) or deeper in body near nerve plexuses (plexiform neurofibroma). While neurofibromas have been known to be Schwann cell tumors for many years, the exact timing and initiating cell has remained elusive. This has led to difficulties in developing animal models and successful therapies for NF1. A culmination of recent genetic studies has finally begun to shed light on the detailed cellular origins of neurofibromatosis. In this review, we will examine the hunt for neurofibroma tumor cells of origin through a historical lens, detailing the genetic systems used to delineate the source of plexiform and cutaneous neurofibromas. Through these novel findings, we can better understand the cellular, temporal, and developmental context during tumor initiation. By leveraging this data, we hope to uncover new therapeutic targets and mechanisms to treat NF1 patients.

Management of cutaneous neurofibroma: current therapy and future directions

Neurofibromatosis type 1 (NF1) is a life-long neurocutaneous disorder characterized by a predisposition to tumor development, including cutaneous neurofibroma (cNF), the hallmark of the disease. cNF is a histologically benign, multicellular tumor formed in virtually most individuals with NF1. It is considered the most burdensome feature of the disorder due to their physical discomfort, cosmetically disfiguring appearance, and psychosocial burden. Management of cNF remains a challenge in the medical field. Effective medicinal treatment for cNF does not exist at this time. Trials aimed at targeting individual components of the neoplasm such as mast cells with Ketotifen have not shown much success. Physical removal or destruction has been the mainstay of therapy. Surgical removal gives excellent cosmetic results, but risk in general anesthesia may require trained specialists. Destructive laser such as CO2 laser is effective in treating hundreds of tumors at one time but has high risk of scarring hypopigmentation or hyperpigmentation that alter cosmetic outcomes. A robust, low-risk surgical technique has been developed, which may be performed in clinic using traditional biopsy tools that may be more accessible to NF1 patients worldwide than contemporary techniques including Er:YAG or Nd:YAG laser. In this review, specific recommendations for management of cNFs are made based on symptoms, clinical expertise, and available resources. Additionally, antiproliferative agents aimed at stimulating cellular quiescence are explored.