Neurofibromatosis 1: clinical manifestations and diagnostic criteria

Analysis of visual evoked potentials in patients with neurofibromatosis type 1: new concepts

Introduction

Neurofibromatosis type 1 (NF type 1) is an autosomal dominant disease with typical clinical manifestations, such as skin lesions, Lisch nodules, optic pathway gliomas, and neurofibromas, caused by the mutation of the NF1 gene. Visual evoked potentials (VEP) present a measure of the electrophysiological response of visual cortex to a visual stimulus. The role of VEP in the pathophysiology of NF type 1 is very complex and requires additional research.

The Aim

We examined the differences between NF type 1 patients with normal and altered VEP and analyzed the correlation between the prolongation of P100 latency and disease severity.

Materials and methods

Two groups were formed: a control group and a study group with NF type 1 patients. Based on the control group analysis, a threshold value for a normal VEP finding of 116 ms was obtained, and it was used to divide the study group into subgroups with normal and altered VEP. We proceeded with examining the differences in clinical manifestations of the disease between the subgroups, after which we checked if there is a correlation between the prolongation of the P100 latency and the severity of the clinical picture according to the Riccardi scale. Statistical analysis was performed using the Pearson chi-square test and the Spearman correlation test in the program SPSS 28.0, with levels of statistical significance p = 0.05 and p = 0.001.

Results

In the group with the abnormal VEP we found a statistically significant more frequent occurrence of optic tract glioma (p = 0.008), tumors (p = 0.032), epilepsy (p = 0.043), and cognitive disorders (p = 0.028), while the other clinical signs had an equal prevalence in both groups. A moderately strong correlation (r s = 0.665) was observed between the prolongation of P100 latency and the severity of the clinical picture.

Conclusion

Our results showed the important role of VEP in the description of clinical phenotypes of NF type 1. The authors of the study propose VEP to be included in the diagnostic algorithms designed for patients with NF type 1.

Contemporary Approach to Neurofibromatosis Type 1-Associated Malignant Peripheral Nerve Sheath Tumors

Most malignant peripheral nerve sheath tumors (MPNSTs) are clinically aggressive high-grade sarcomas, arising in individuals with neurofibromatosis type 1 (NF1) at a significantly elevated estimated lifetime frequency of 8%-13%. In the setting of NF1, MPNSTs arise from malignant transformation of benign plexiform neurofibroma and borderline atypical neurofibromas. Composed of neoplastic cells from the Schwannian lineage, these cancers recur in approximately 50% of individuals, and most patients die within five years of diagnosis, despite surgical resection, radiation, and chemotherapy. Treatment for metastatic disease is limited to cytotoxic chemotherapy and investigational clinical trials. In this article, we review the pathophysiology of this aggressive cancer and current approaches to surveillance and treatment.

Development and pilot validation of a novel disfigurement severity scale for plexiform neurofibromas in children with neurofibromatosis type 1

BACKGROUND/AIMS

We developed an observer disfigurement severity scale for neurofibroma-related plexiform neurofibromas to assess change in plexiform neurofibroma-related disfigurement and evaluated its feasibility, reliability, and validity.

METHODS

Twenty-eight raters, divided into four cohorts based on neurofibromatosis type 1 familiarity and clinical experience, were shown photographs of children in a clinical trial (NCT01362803) at baseline and 1 year on selumetinib treatment for plexiform neurofibromas (n = 20) and of untreated participants with plexiform neurofibromas (n = 4). Raters, blinded to treatment and timepoint, completed the 0-10 disfigurement severity score for plexiform neurofibroma on each image (0 = not at all disfigured, 10 = very disfigured). Raters evaluated the ease of completing the scale, and a subset repeated the procedure to assess intra-rater reliability.

RESULTS

Mean baseline disfigurement severity score for plexiform neurofibroma ratings were similar for the selumetinib group (6.23) and controls (6.38). Mean paired differences between pre- and on-treatment ratings was -1.01 (less disfigurement) in the selumetinib group and 0.09 in the control (p = 0.005). For the disfigurement severity score for plexiform neurofibroma ratings, there was moderate-to-substantial agreement within rater cohorts (weighted kappa range = 0.46-0.66) and agreement between scores of the same raters at repeat sessions (p > 0.05). In the selumetinib group, change in disfigurement severity score for plexiform neurofibroma ratings was moderately correlated with change in plexiform neurofibroma volume with treatment (r = 0.60).

CONCLUSION

This study demonstrates that our observer-rated disfigurement severity score for plexiform neurofibroma was feasible, reliable, and documented improvement in disfigurement in participants with plexiform neurofibroma shrinkage. Prospective studies in larger samples are needed to validate this scale further.

KIT Mutation Associated with Depigmented Patches Regression and Multiple Café-au-lait Macules Development in a Patient with Piebaldism: A Case Report

Piebaldism is a rare genetic disorder caused by KIT mutations and clinically characterized by fixed depigmented patches throughout the body. Herein, a case of piebaldism in which the depigmented patches regressed as the patient grew older, along with the development of multiple café-au-lait macules, is described. The likely pathogenic, heterozygous KIT c.1991-2A>G variant was detected as the potential cause of this unusual piebaldism phenotype. This case provides new knowledge on genotype-phenotype correlation of KIT mutations for piebaldism etiology and presentation.

Perinatal folate levels do not influence tumor latency or multiplicity in a model of NF1 associated plexiform-like neurofibromas

OBJECTIVE

In epidemiological and experimental research, high folic acid intake has been demonstrated to accelerate tumor development among populations with genetic and/or molecular susceptibility to cancer. Neurofibromatosis type 1 (NF1) is a common autosomal dominant disorder predisposing affected individuals to tumorigenesis, including benign plexiform neurofibromas; however, understanding of factors associated with tumor risk in NF1 patients is limited. Therefore, we investigated whether pregestational folic acid intake modified plexiform-like peripheral nerve sheath tumor risk in a transgenic NF1 murine model.

RESULTS

We observed no significant differences in overall survival according to folate group. Relative to controls (180 days), median survival did not statistically differ in deficient (174 days, P = 0.56) or supplemented (177 days, P = 0.13) folate groups. Dietary folate intake was positively associated with RBC folate levels at weaning, (P = 0.023, 0.0096, and 0.0006 for deficient vs. control, control vs. supplemented, and deficient vs. supplemented groups, respectively). Dorsal root ganglia (DRG), brachial plexi, and sciatic nerves were assessed according to folate group. Mice in the folate deficient group had significantly more enlarged DRG relative to controls (P = 0.044), but no other groups statistically differed. No significant differences for brachial plexi or sciatic nerve enlargement were observed according to folate status.

Clinical and imaging modality factors impacting radiological interpretation of breast screening in young women with neurofibromatosis type 1

Young women with Neurofibromatosis type 1 (NF1) have a high risk of developing breast cancer and poorer survival following breast cancer diagnosis. International guidelines recommend commencing breast screening between 30 and 35 years; however, the optimal screening modality is unestablished, and previous reports suggest that breast imaging may be complicated by the presence of intramammary and cutaneous neurofibromas (cNFs). The aim of this study was to explore potential barriers to implementation of breast screening for young women with NF1.Twenty-seven women (30-47 years) with NF1 completed breast screening with breast MRI, mammogram and breast ultrasound. Nineteen probably benign/suspicious lesions were detected across 14 women. Despite the presence of breast cNFs, initial biopsy rate for participants with NF1 (37%), were comparable to a BRCA pathogenic variant (PV) cohort (25%) (P = 0.311). No cancers or intramammary neurofibromas were identified. Most participants (89%) returned for second round screening.The presence of cNF did not affect clinician confidence in 3D mammogram interpretation, although increasing breast density, frequently seen in young women, impeded confidence for 2D and 3D mammogram. Moderate or marked background parenchymal enhancement on MRI was higher in the NF1 cohort (70.4%) than BRCA PV carriers (47.3%), which is an independent risk factor for breast cancer.Breast MRI was the preferred mode of screening over mammogram, as the majority (85%) with NF1 demonstrated breast density (BI-RADS 3C/4D), which hinders mammogram interpretation. For those with high breast density and high cNF breast coverage, 3D rather than 2D mammogram is preferred, if MRI is unavailable.

Superimposed Mosaicism in the Form of Extremely Extended Segmental Plexiform Neurofibroma Caused by a Novel Pathogenic Variant in the NF1 Gene

Plexiform neurofibromas occurring in approximately 20-50% of all neurofibromatosis type-1 (NF1) cases are histologically benign tumors, but they can be fatal due to compression of vital structures or transformation to malignant sarcomas or malignant peripheral nerve sheath tumors. All sizeable plexiform neurofibromas are thought to result from an early second mutation giving rise to a loss of heterozygosity of the NF1 gene. In this unusual case, a 12-year-old girl presented with a rapidly growing, extremely extensive plexiform neurofibroma with segmental distribution over the entire right arm, extending to the right chest wall and mediastinum, superimposed on classic cutaneous lesions of NF1. After several surgical interventions, the patient was efficiently treated with an oral selective MEK inhibitor, selumetinib, which resulted in a rapid reduction of the tumor volume. Molecular analysis of the NF1 gene revealed a c.2326-2 A>G splice-site mutation in the clinically unaffected skin, peripheral blood sample, and plexiform neurofibroma, which explains the general clinical symptoms. Furthermore, a novel likely pathogenic variant, c.4933dupC (p.Leu1645Profs*7), has been identified exclusively in the girl's plexiform neurofibromas. This second-hit mutation can explain the extremely extensive segmental involvement.

Olfactory groove monophasic sinovial sarcoma and von Recklinghausen's disease: A case report and literature review

BACKGROUND

Soft-tissue sarcomas are a rare and diverse group of neoplastic lesions. They represent only 1% of malignant tumors in adults and 15% in children. Synovial sarcoma (SS) is a type of soft-tissue sarcoma, accounting for 5-10% of cases, and commonly affecting extremities. Diagnosis, treatment, and prognosis remain challenging especially when localized in uncommon areas, such as intracranial lesions.

CASE DESCRIPTION

A 13-year-old male patient with a clinical history of neurofibromatosis Type I (NF1) presenting holocranial headache with jet vomiting and apathy 2 days before admission, without neurological deficits and/or focal findings. On magnetic resonance imaging: an extra-axial infiltrative lesion with contrast uptake at the base of the skull in the olfactory groove topography. After total tumor resection, the anatomopathological examination showed monophasic SS. The patient returned after 6 months with similar symptoms, and the lesion recurred and was reoperated. Unfortunately, 7 months after the second surgery, the patient died.

CONCLUSION

SS can occur extraarticulously and with a variable clinical presentation and poor prognosis despite adjuvant therapies with radiotherapy and chemotherapy. In individuals with clinical history of NF1, there is still no direct correlation between the two manifestations, although current descriptions are suggestive of a possible interaction.

French cohort of children and adolescents with neurofibromatosis type 1 and symptomatic inoperable plexiform neurofibromas: CASSIOPEA study

Surgery is a treatment option for neurofibromatosis type 1 (NF1)-related plexiform neurofibromas (PN), but complete resection is often not feasible. Real-world studies are warranted to understand disease burden, progression, and need for medical treatment in patients with inoperable PN. CASSIOPEA was a retrospective study of French pediatric patients (aged ≥3 to <18 years) presenting at a national multidisciplinary team (MDT) review with NF1 and ≥1 symptomatic, inoperable PN. Medical records were reviewed from the time of MDT review and over a follow-up period of up to 2 years. Primary objectives were to describe patient characteristics and target PN-associated therapy patterns. A secondary objective was evolution of target PN-related morbidities. Patients with prior, ongoing, or MDT recommendation of mitogen-activated protein kinase kinase (MEK) inhibitor treatment were excluded. Overall, 78 target PN were identified in 76 patients. At MDT review, median age was 8.4 years, with approximately 30% of patients aged 3-6 years. Target PN were primarily internal (77.3%), and 43.2% were progressive. Target PN location was evenly distributed. 34 target PN had documented MDT recommendations; of these, a majority (76.5%) were for non-medication management, including surveillance. At least one follow-up visit was recorded for 74 target PN. Despite initially being considered inoperable, 12.3% of patients underwent surgery for target PN. At MDT review, most (98.7%) target PN were associated with ≥1 morbidity, primarily pain (61.5%) and deformity (24.4%); severe morbidities were identified in 10.3%. Of 74 target PN with follow-up data, 89.2% were associated with ≥1 morbidity, primarily pain (60.8%) and deformity (25.7%). Of 45 target PN associated with pain, pain improved in 26.7%, was stable in 44.4%, and deteriorated in 28.9%. Deformity improved in 15.8% and remained stable in 84.2% of 19 target PN associated with deformity. None deteriorated. In this real-world study in France, NF1-PN disease burden was considerable, and a considerable proportion of patients were very young. Most patients received only supportive care without medication for target PN management. Target PN-related morbidities were frequent, heterogeneous, and generally did not improve during follow-up. These data highlight the importance of effective treatments that target PN progression and improve disease burden.

Clinical evaluation of muscle functions in neurofibromatosis type 1

AIM

Muscle weakness, fatigue and speech problems can occur in neurofibromatosis type 1 (NF1). The pathogenesis of these symptoms is unclear, likely multifactorial. We examined motor function in limb and speech muscles in NF1 patients.

METHODS

We evaluated NF1 and control groups aged 4-18 years for muscle strength, tone and mobility using standard manual testing, joint motion and Beighton score measurements. Speech and language functions were assessed by speech articulation and resonance. As a marker of muscle tissue turnover, we determined collagen degradation products in urine before and after submaximal exercise.

RESULTS

NF1 patients had reduced strength in proximal limb muscles compared to control subjects. Speech articulation problems and hypernasality were more common in NF1 (47% and 38%, respectively). Collagen products excreted in urine correlated with gluteal and biceps muscle strength.

CONCLUSION

Muscle dysfunction can be detected in some children with NF1 and may explain certain clinical features including fatigue, speech and articulation problems. If confirmed by further research, these findings may be relevant to the management of this condition.

RETRACTED: A case report of a 4-year-old girl with neurofibromatosis type 1

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Authors. A diagnostic discordance in the original pathology reports has been noticed and requires further evaluation, therefore the paper will be retracted.

Familial left cervical neurofibromatosis 1 with scoliosis: A case report

BACKGROUND

Neurofibromatosis type 1 (NF1) is an inherited autosomal dominant disorder affecting many parts of the body with café au lait spots, skeletal deformity, and scoliosis. A familial case of NF1 with scoliosis and a painless mass had not yet been reported.

CASE SUMMARY

We describe the case of a 15-year-old male patient with a painless lump on the left side of his neck for 10 years and scoliosis. His right shoulder was about 5 cm lower than the left, the left side of his face was deformed, and the left submandibular skin was relaxed. The folding and drooping were obvious and movement was poor. Computed tomography revealed the involvement of the neck, upper chest wall, and surrounding left shoulder, accompanied by bone changes and scoliosis. Histological evaluation showed subepidermal pale blue mucoid degeneration, fibrous fusiform cells in the dermis in a fascicular, woven arrangement. His mother had the same medical history. The diagnosis was neurofibromatosis of the left neck. Various parts of the tumor tissue were serially resected during several visits. Eight months after surgery, there was a slight tendency to regrow.

CONCLUSION

This case of slow-progressing NF1 highlights the importance of early diagnosis and treatment to reduce its impact on the patient’s growth and development.

FDA Approval Summary: Selumetinib for Plexiform Neurofibroma

On April 10, 2020, the FDA approved selumetinib (KOSELUGO, AstraZeneca) for the treatment of pediatric patients 2 years of age and older with neurofibromatosis type 1 who have symptomatic, inoperable plexiform neurofibromas. Approval was based on demonstration of a durable overall response rate per Response Evaluation in Neurofibromatosis and Schwannomatosis criteria and supported by observed clinical improvements in plexiform neurofibroma-related symptoms and functional impairments in 50 pediatric patients with inoperable plexiform neurofibromas in a single-arm, multicenter trial. The overall reponse rate per NCI investigator assessment was 66% (95% confidence interval, 51-79) with at least 12 months of follow-up. The median duration of response was not reached, and 82% of responding patients experienced duration of response ≥12 months. Clinical outcome assessment endpoints provided supportive efficacy data. Risks of selumetinib are consistent with MAPK (MEK) inhibitor class effects, including ocular, cardiac, musculoskeletal, gastrointestinal, and dermatologic toxicities. Safety was assessed across a pooled database of 74 pediatric patients with plexiform neurofibromas and supported by adult and pediatric selumetinib clinical trial data in cancer indications. The benefit-risk assessment for selumetinib in patients with inoperable plexiform neurofibromas was considered favorable.

L-carnitine supplementation for muscle weakness and fatigue in children with neurofibromatosis type 1: A Phase 2a clinical trial

Reduced muscle tone, muscle weakness, and physical fatigue can impact considerably on quality of life for children with neurofibromatosis type 1 (NF1). Human muscle biopsies and mouse models of NF1 deficiency in muscle show intramyocellular lipid accumulation, and preclinical data have indicated that L-carnitine supplementation can ameliorate this phenotype. The aim of this study is to examine whether daily L-carnitine supplementation is safe and feasible, and will improve muscle strength and reduce fatigue in children with NF1. A 12-week Phase 2a trial was conducted using 1000 mg daily oral levocarnitine tartrate supplementation. Recruited children were between 8 and 12 years old with a clinical diagnosis of NF1, history of muscle weakness and fatigue, and naïve to L-carnitine. Primary outcomes were safety (self-reporting, biochemical testing) and compliance. Secondary outcomes included plasma acylcarnitine profiles, functional measures (muscle strength, long jump, handwriting speed, 6-minute-walk test [6MWT]), and parent-reported questionnaires (PedsQL™, CBCL/6-18). Six children completed the trial with no self-reported adverse events. Biochemical tests for kidney and liver function were normal, and the average compliance was 95%. Plasma acylcarnitine levels were low, but within a range not clinically linked to carnitine deficiency. For strength measures, there was a mean 53% increase in dorsiflexion strength (95% confidence interval [CI] 8.89-60.75; p = 0.02) and mean 66% increase in plantarflexion strength (95% CI 12.99-134.1; p = 0.03). In terms of muscle performance, there was a mean 10% increase in long jump distance (95% CI 2.97-16.03; p = 0.01) and 6MWT distance (95% CI 5.88-75.45; p = 0.03). Comparison with the 1000 Norms Project data showed a significant improvement in Z-score for all of these measures. Parent reports showed no negative impact on quality of life, and the perceived benefits led to the majority of individuals remaining on L-carnitine after the study. Twelve weeks of L-carnitine supplementation is safe and feasible in children with NF1, and a Phase 3 trial should confirm the efficacy of treatment.

Clinical spectrum of neurofibromatosis type 1 among children in a tertiary care center

Objectives:

To identify the clinical and neuroradiological features of neurofibromatosis type 1 and the risk of malignancy in a pediatric age group.

Methods:

This observational retrospective cohort study was conducted at King Saud University Medical City, Riyadh, Kingdom of Saudi Arabia, for the patients with neurofibromatosis type 1 who were seen and had follow up from January 2000 to January 2019.

Results:

A total of 50 children were included. Approximately 90% of patients presented with café-au-lait macules, and 34% had skin-fold freckling. Moreover, 42% of the participants had a first-degree relative with neurofibromatosis type 1, and about a quarter presented with associated epilepsy. About 90% of the neuroradiological features were consistent with those of neurofibromatosis type 1. About 52% of the patients had one or multiple types of tumors, and 34% presented with optic pathway glioma.

Conclusion:

This study described clinical spectrum of neurofibromatosis type 1 among children. It showed also a higher percentage of tumors than previous studies.

Neurofibromatosis -1 diagnosed from an intraoral swelling - a case series

The neurofibromatoses [NF 1, NF 2 and schwannomatosis] are a group of genetic disorders that lead to the development of nervous system tumours and have diverse dermatologic, neurologic, ophthalmic, skeletal and vascular effects. The most common is NF 1 (Neurofibromatosis 1) also known as von Recklinghausen's disease, which is one of the most common human genetic diseases. Oral manifestations of NF 1 are reported in 72% of cases and in one of our cases precipitated attendance at a general dental practitioner (GDP), subsequent diagnosis and genetic screening for family members. This disease may go undiagnosed due to its variable expressivity of symptoms. The pivotal importance of a GDP in the discovery and early referral to an oral or oral and maxillofacial surgeon for further investigation and diagnosis of this condition is highlighted. Knowledge of the most common features of neurofibromatosis can facilitate the speedy referral and subsequent diagnosis of generalized neurofibromatosis, local surgical management of benign neoplasms and long term management of its other clinical features. Dentists should be aware of the classic symptoms of this condition and of their role in long-term care in view of the risk of local recurrence and malignant transformation.

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.

Cognitive functioning and pain interference mediate pain predictive effects on health-related quality of life in pediatric patients with Neurofibromatosis Type 1

OBJECTIVES

The objective was to investigate the serial mediating effects of perceived cognitive functioning and pain interference in daily living in the relationship between perceived pain and overall generic health-related quality of life (HRQOL) in children, adolescents, and young adults with Neurofibromatosis Type 1 (NF1).

METHODS

The Pain, Cognitive Functioning, and Pain Impact Scales from the PedsQL Neurofibromatosis Type 1 Module and the PedsQL 4.0 Generic Core Scales were completed in a multi-site national study by 323 patients ages 5-25 and 335 parents. A serial multiple mediator model analysis was conducted to test the hypothesized sequential mediating effects of cognitive functioning and pain interference as intervening variables in the association between pain as a predictor variable and overall generic HRQOL.

RESULTS

Pain predictive effects on overall generic HRQOL were serially mediated by cognitive functioning and pain interference. In predictive analytics models utilizing hierarchical multiple regression analyses with age and gender demographic covariates, pain, cognitive functioning and pain interference accounted for 66% of the variance in patient-reported generic HRQOL and 57% of the variance in parent proxy-reported generic HRQOL (P < 0.001), reflecting large effect sizes.

CONCLUSIONS

Cognitive functioning and pain interference explain in part the mechanism of pain predictive effects on overall generic HRQOL in pediatric patients with NF1. Identifying NF1-specific pain, cognitive functioning, and pain interference as salient predictors of overall generic HRQOL from the patient and parent perspective facilitates a family-centered orientation to the comprehensive care of children, adolescents, and young adults with NF1.

Evaluating modified diets and dietary supplement therapies for reducing muscle lipid accumulation and improving muscle function in neurofibromatosis type 1 (NF1)

Neurofibromatosis type 1 (NF1) is a genetic disorder that affects a range of tissue systems, however the associated muscle weakness and fatigability can have a profound impact on quality of life. Prior studies using the limb-specific Nf1 knockout mouse (Nf1_Prx1^-/-) revealed an accumulation of intramyocellular lipid (IMCL) that could be rescued by a diet supplemented with L-carnitine and enriched for medium-chain fatty acids (MCFAs). In this study we used the Nf1_Prx1^-/- mouse to model a range of dietary interventions designed to reduce IMCL accumulation, and analyze using other modalities including in situ muscle physiology and lipid mass spectrometry. Histological IMCL accumulation was significantly reduced by a range of treatments including L-carnitine and high MCFAs alone. A low-fat diet did not affect IMCL, but did provide improvements to muscle strength. Supplementation yielded rapid improvements in IMCL within 4 weeks, but were lost once treatment was discontinued. In situ muscle measurements were highly variable in Nf1_Prx1^-/- mice, attributable to the severe phenotype present in this model, with fusion of the hips and an overall small hind limb muscle size. Lipidome analysis enabled segregation of the normal and modified chow diets, and fatty acid data suggested increased muscle lipolysis with the intervention. Acylcarnitines were also affected, suggestive of a mitochondrial fatty acid oxidation disorder. These data support the theory that NF1 is a lipid storage disease that can be treated by dietary intervention, and encourages future human trials.

Congenital abnormalities of the retinal vasculature in neurofibromatosis type I

The aim of this cross-sectional study was to investigate congenital abnormalities of the retinal vasculature (CARVs) in patients with neurofibromatosis type I (NF-1). Forty-eight patients (96 eyes) with NF-1 diagnosed according to the National Institutes of Health (NIH) criteria and 48 healthy controls were included in this study. Standard fundus photographs were obtained for each subject to evaluate the presence and frequency of CARVs. The sensitivity, specificity, and diagnostic accuracy of different cut-off numbers of CARVs were compared with those of the NIH criteria. Forty-four (91.7%) patients in the NF-1 group demonstrated either supranumeraty optic disc vessels or triple branching of the retinal vasculature, and 22 patients (45.8%) demonstrated both findings. The frequencies of these two CARVs were significantly different between the two groups (p < 0.00001). A cut-off value of either one for supranumerary optic disc vessels or triple branching showed the highest accuracy along with sensitivity and specificity of 91.7% and 87.5%. CARVs such as supranumerary optic disc vessels or triple branching were frequently observed in NF-1 patients, and their occurrence was unrelated to the age of patients. Thus, these CARVs could be added as new ophthalmologic manifestions for NF-1 and may potentially enable early diagnosis of NF-1.

Therapeutic Effects of Apamin as a Bee Venom Component for Non-Neoplastic Disease

Bee venom is a natural toxin produced by honeybees and plays an important role in defending bee colonies. Bee venom has several kinds of peptides, including melittin, apamin, adolapamine, and mast cell degranulation peptides. Apamin accounts for about 2%-3% dry weight of bee venom and is a peptide neurotoxin that contains 18 amino acid residues that are tightly crosslinked by two disulfide bonds. It is well known for its pharmacological functions, which irreversibly block Ca2+-activated K+ (SK) channels. Apamin regulates gene expression in various signal transduction pathways involved in cell development. The aim of this study was to review the current understanding of apamin in the treatment of apoptosis, fibrosis, and central nervous system diseases, which are the pathological processes of various diseases. Apamin's potential therapeutic and pharmacological applications are also discussed.

Epithelioid sarcoma associated with neurofibromatosis type I

In general, patients with neurofibromatosis type I have a higher risk than those with other types of neurofibromatosis of developing soft-tissue sarcomas related to the nervous system. We here present a 42-year-old man with neurofibromatosis type I who developed a protruding mass over only 2 weeks. The histopathological diagnosis was epithelioid sarcoma. Epithelioid sarcomas are rare and, to the best of our knowledge, no epithelioid sarcomas have been reported in patients with neurofibromatosis type I. Radical excision of the primary lesion was performed and postoperative radiotherapy and chemotherapy administered, as is recommended for epithelioid sarcoma. Our case emphasizes that patients with neurofibromatosis type I may develop malignant tumors

Neurofibromatosis 1 French national guidelines based on an extensive literature review since 1966

Neurofibromatosis type 1 is a relatively common genetic disease, with a prevalence ranging between 1/3000 and 1/6000 people worldwide. The disease affects multiple systems with cutaneous, neurologic, and orthopedic as major manifestations which lead to significant morbidity or mortality. Indeed, NF1 patients are at an increased risk of malignancy and have a life expectancy about 10-15 years shorter than the general population. The mainstay of management of NF1 is a patient-centered longitudinal care with age-specific monitoring of clinical manifestations, aiming at the early recognition and symptomatic treatment of complications as they occur. Protocole national de diagnostic et de soins (PNDS) are mandatory French clinical practice guidelines for rare diseases required by the French national plan for rare diseases. Their purpose is to provide health care professionals with guidance regarding the optimal diagnostic and therapeutic management of patients affected with a rare disease; and thus, harmonizing their management nationwide. PNDS are usually developed through a critical literature review and a multidisciplinary expert consensus. The purpose of this article is to present the French guidelines on NF1, making them even more available to the international medical community. We further dwelled on the emerging new evidence that might have therapeutic potential or a strong impact on NF1 management in the coming feature. Given the complexity of the disease, the management of children and adults with NF1 entails the full complement healthcare providers and communication among the various specialties.

Subperiosteal hemorrhage: A rare complication in neurofibromatosis which may mimic malignant peripheral nerve sheath tumor

Currently, there is little in the medical literature on subperiosteal hematomas in neurofibromatosis patients, particularly in those who have subperiosteal neurofibromas. Initial imaging and clinical presentation can be very worrisome and to the unaware may lead to early surgical intervention and/or anxiety in the patient and parents. This report presents the case of a 9-year-old child with neurofibromatosis type-1 and progressively increasing calf pain and swelling about a known plexiform neurofibroma. Imaging at initial presentation and at 1 month demonstrated evolving subperiosteal hemorrhage. This report adds to the small body of literature on subperiosteal hemorrhage as a complication of neurofibromatosis. Additionally, this report demonstrates an approach to noninvasive management of these lesions with the utility of initial and 1 month follow-up radiographs helpful in demonstrating hemorrhage evolution and possibly negating the need for biopsy.

When Low Bone Mineral Density and Fractures Is Not Osteoporosis

PURPOSE OF REVIEW

To review the differential diagnosis of low bone mineral density (BMD).

RECENT FINDINGS

Osteoporosis is the most common cause of low BMD in adults; however, non-osteoporotic causes of low BMD should be considered in the differential diagnosis of patients with low BMD. Mild osteogenesis imperfecta, osteomalacia, and mineral and bone disorder of chronic kidney disease as well as several other rare diseases can be characterized by low BMD. This review summarizes the differential diagnosis of low BMD. It is important to differentiate osteoporosis from other causes of low BMD since treatment regimens can vary tremendously between these different disease processes. In fact, some treatments for osteoporosis could worsen or exacerbate the mineral abnormalities in other causes of low BMD.

Piebaldism Associated with Café-au-lait Macules and Intertriginous Freckling: A Case Report and Review of the Literature

We present 9-year-old fraternal twins from a family with piebaldism, having congenital depigmented macules and meeting the diagnostic criteria for neurofibromatosis type 1 (NF1) due to the multiple café-au-lait macules (CALMs) and intertriginous freckling at the same time. It's still a debatable issue that CALMs and intertriginous freckling may be seen in the clinical spectrum of piebaldism or these patients should be regarded as coexistence of piebaldism and NF1. However, based on recent literature and our patients' findings, we suggest that this rare phenotypic variant of piebaldism may not need the careful clinical follow-up and molecular testing for NF1. Besides, it may be suitable that these individuals with piebaldism showing NF1-like clinical phenotypes should be further tested for KIT and SPRED1 gene mutations.

The characteristics of 76 atypical neurofibromas as precursors to neurofibromatosis 1 associated malignant peripheral nerve sheath tumors

Background

Neurofibromatosis 1 (NF1) leads to the development of benign and malignant peripheral nerve sheath tumors (MPNST). MPNST have been described to develop in preexisting benign plexiform neurofibromas (PN) and have a poor prognosis. Atypical neurofibromas (ANF) were recently described as precursor lesions for MPNST, making early detection and management of ANF a possible strategy to prevent MPNST. We aimed to clinically characterize ANF and identify management approaches.

Methods

We analyzed clinical, imaging, and pathology findings of all patients with NF1 and ANF at 3 institutions.

Results

Sixty-three patients had 76 ANF (32M/31F; median age 27.1 y). On MRI, most ANF appeared as distinct nodular lesions and were 18F-fluorodeoxyglucose (FDG) avid. Forty-six ANF were associated with pain, 19 with motor weakness, 45 were palpable or visible, and 13 had no clinical signs. Completely resected ANF (N = 57) have not recurred (median follow-up, 4.1 y; range, 0-14 y). Four ANF transformed into MPNST and 17 patients had a history of MPNST in a different location than was their ANF.

Conclusions

Growth of distinct nodular lesions, pain, and FDG-PET avidity should raise concern for ANF in NF1. Patients with ANF are at greater risk for development of MPNST. Complete resection of ANF may prevent development of MPNST.

Lifespan Development: Symptoms Experienced by Individuals with Neurofibromatosis Type 1 Associated Plexiform Neurofibromas from Childhood into Adulthood

This secondary data analysis qualitatively identified salient concerns reported by individuals with Neurofibromatosis Type 1 (NF1)-associated plexiform neurofibromas (pNFs) at different stages of development. Past literature has focused on overall symptomatology, but has not examined nuances in how these symptoms are experienced across developmental phases. Therefore, we aimed to identify commonalities and differences in symptom experiences across age groups to better assist individuals to adjust to symptoms across the lifespan. Thirty-one children, adolescents, and adults (age ≥ 5 years old) and 15 parents participated in semi-structured interviews. Analyses focused on the following symptom categories: pain, social functioning, physical function impact, and stigma. Aspects of pain endorsed by all age groups included localized brief pain on contact with pNF and abnormal sensations; however, only adolescents and adults reported chronic pain and change in pain over time. Social functioning themes of limited activity participation, role limitations, and relationship impact were endorsed by all age groups, but differences emerged across age groups in the types of activity and role limitations, the type of relationship impact, and family planning concerns. All age groups described difficulty with mobility, but only parents reported problems with coordination and physical developmental milestones. While all age groups reported external stigma, internalized stigma was predominately endorsed by adults. While individuals in all age groups described pNF concerns related to pain, social function, physical function, and stigma, specific aspects of these symptoms differed across the developmental continuum. These findings can help assist individuals with pNF better transition to the next developmental phases.

PedsQL Neurofibromatosis Type 1 Module for children, adolescents and young adults: feasibility, reliability, and validity

The objective of the present study was to report on the measurement properties of the Pediatric Quality of Life Inventory (PedsQL) Neurofibromatosis Type 1 Module for pediatric patients ages 5-25 from the perspectives of patients and parents. The 104-item PedsQL NF1 Module and 23-item PedsQL Generic Core Scales were completed in a multi-site national study by 323 patients and 335 parents (343 families). Patients were diagnosed with NF1 using the National Institutes of Health diagnostic criteria. In addition to a Total Scale Score, 18 unidimensional scales were derived measuring skin itch bother, skin sensations, pain, pain impact, pain management, cognitive functioning, speech, fine motor, balance, vision, perceived physical appearance, communication, worry, treatment anxiety, medicines, stomach discomfort, constipation, and diarrhea. The PedsQL NF1 Module Scales evidenced excellent feasibility, excellent reliability for the Total Scale Scores (patient self-report α = 0.98; parent proxy-report α = 0.98), and good to excellent reliability for the 18 individual scales (patient self-report α = 0.71-0.96; parent proxy-report α = 0.73-0.98). Intercorrelations with the Generic Core Scales supported construct validity. Factor analysis supported the unidimensionality of the 18 individual scales. The PedsQL NF1 Module Scales demonstrated acceptable to excellent measurement properties, and may be utilized as standardized metrics to assess NF1-specific symptoms and problems in clinical research and practice in children, adolescents, and young adults.

Plexiform Schwannoma of the Finger: A Case Report and Literature Review

A 49-year-old woman with a long history of a subcutaneous mass on the dorsal side of her 4^th finger of the right hand visited a dermatologist because of slight enlargement of the mass. Her past medical history was notable only for a mitral valvuloplasty performed 20 years earlier. Physical examination revealed a small, round, firm subcutaneous mass on the dorsal side of her proximal interphalangeal joint of the right 4^th finger. The mass was immobile and nontender and its overlying skin was intact. An excisional biopsy was done for the patient and the specimen was sent for pathologic evaluation. On microscopic examination, the final diagnosis of plexiform schwannoma was made for the lesion. The aim of this publication is to report a rare case of plexiform schwannoma of the soft tissue and a literature review to provide a better understanding about its characteristics including epidemiologic factors and pathologic evaluation.

Dissecting Clinical Heterogeneity in Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is a common neurogenetic disorder in which affected children and adults are predisposed to the development of benign and malignant nervous system tumors. Caused by a germline mutation in the NF1 tumor suppressor gene, individuals with NF1 are prone to optic gliomas, malignant gliomas, neurofibromas, and malignant peripheral nerve sheath tumors, as well as behavioral, cognitive, motor, bone, cardiac, and pigmentary abnormalities. Although NF1 is a classic monogenic syndrome, the clinical features of the disorder and their impact on patient morbidity are variable, even within individuals who bear the same germline NF1 gene mutation. As such, NF1 affords unique opportunities to define the factors that contribute to disease heterogeneity and to develop therapies personalized to a given individual (precision medicine). This review highlights the clinical features of NF1 and the use of genetically engineered mouse models to define the molecular and cellular pathogenesis of NF1-associated nervous system tumors.

A 40-Year-Old Woman With Back Pain

A 40-year-old woman consulted our ED for a 7-month history of left dorsal back pain and dyspnea. The pain was initially dull and mechanical. Her general practitioner started nonsteroidal antiinflammatory drugs and physiotherapy, which provided partial relief. One week before consulting, the intensity of the pain increased, and she started to feel shortness of breath when performing her daily activities. She had lost 5 kg during the previous month. The patient was a healthy woman who lived in an urban area of Barcelona, Spain. She did not smoke or take drugs of abuse, and she worked as a butcher. During the initial evaluation, her blood pressure was 131/76 mm Hg, heart rate was 120 beats/min, temperature was 36.2°C, and ambient air pulse oximetry was 98%.

Neurofibromatosis Clinic: A Report on Patient Demographics and Evaluation of the Clinic

BACKGROUND

Neurofibromatosis type 1 (NF1) is a common single-gene disorder. A multidisciplinary approach to the management of NF1 patients is necessitated by the heterogeneity of clinical manifestations. Although multidisciplinary paediatric clinics have been well established, there is a dearth of such resources for adults with NF1. Herein we report our one-year institutional experience with a multidisciplinary adult NF1 clinic.

METHODS

A multidisciplinary team was assembled, and an NF Patient Registry Initiative questionnaire was adapted to collect patient-reported data during clinics. Multiple databases were searched to identify publications pertaining to the experience of other multidisciplinary NF1 clinics focusing on adult patients. Data on patient epidemiology and clinical staff were compared to our data.

RESULTS

A total of 77 patients were scheduled, and 68 attended the clinic, of whom 66 completed the intake questionnaire. The demographic and clinical data from this Canadian population are mostly consistent with previous reports, with some exceptions. Clinical data related to immune system involvement such as asthma, airway/breathing-related difficulties or allergies were striking in our NF1 population. Six relevant published reports of other NF1 clinics were identified. Reports from these studies pertained to periods ranging from 10 to 38 months, and the number of adults assessed ranged from 19 to 177 patients.

CONCLUSIONS

The structure of our clinic and the patient volume are comparable to those of other established centres found in the literature. Our data offer valuable cross-sectional prevalence statistics in the Canadian population. The patient-reported data concerning involvement of the immune system contribute to an emerging recognized medical concern within the NF1 population and warrant further clinical and basic investigation.

Tight Junction Proteins and Perineurial Cells in Neurofibromas

Cutaneous neurofibromas consist of axonal processes, Schwann cells, fibroblasts, perineurial cells, mast cells, and abundant extracellular matrix. The distribution and role of perineurial cells in neurofibromas has been uncertain, partly because there has not been a specific immunohistochemical marker for perineurial cells. In this study, tight junctions (TJs) of 16 neurofibromas from 12 patients with neurofibromatosis type 1 (NF1) were analyzed using electron microscopy, immunohistochemistry, and Western transfer analysis. Cell-cell contacts with typical ultrastructural morphology of TJs were seen between adjacent perineurial cells surrounding the small nerves and between contacting perineurial cell processes embedded in tumor stroma. Immunohistochemistry showed expression of claudin-1, claudin-3, and ZO-1 in the intercellular junctions of a subpopulation of tumor cells. Occludin was present mainly in perineurium and claudin-5 localized to the blood vessels. Double immunolabelings were used to identify the cell types expressing claudin-1. The results showed that claudin-1 positive cells were also positive for type IV collagen and epithelial membrane antigen but not for S-100 protein. This labeling pattern is consistent with perineurial cell phenotype. Using claudin-1 as a marker, our results showed that clusters of perineurial cells are distributed around the rudimentary nerves within cutaneous neurofibromas and at the periphery of some neurofibromas.

Aberrant Myeloid Differentiation Contributes to the Development of Osteoporosis in Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1), also known as von Recklinghausen disease, is a common autosomal dominant genetic disorder affecting approximately 1 in 3000 individuals worldwide. NF1 results from heritable or spontaneous mutations of the NF1 tumor suppressor gene. NF1 encodes the protein neurofibromin, which functions to negatively regulate Ras-activity. Approximately 50 % of NF1 patients develop osteopenia or osteoporosis, resulting in significantly increased rates of long-bone fracture and morbidity. While defective osteoblast bone anabolism has been implicated as a central factor in the pathogenesis of NF1 associated skeletal deficits, recent data suggest that NF1 (Nf1) haploinsufficiency within the hematopoietic compartment, particularly in osteoclasts and myeloid progenitors, plays a pivotal role in engendering NF1 osseous manifestations. In this chapter, we review the latest data from clinical studies and murine models delineating a critical role for hematopoietic compartment, myeloid progenitors of NF1 (Nf1) haploinsufficient and their progeny-osteoclasts, in the pathogenesis of NF1 associated osteopenia/osteoporosis and discuss putative targets for future therapeutics.

Mutational Analysis of Ionizing Radiation Induced Neoplasms

Ionizing radiation (IR) is a mutagen that promotes tumorigenesis in multiple exposure contexts. One severe consequence of IR is the development of second malignant neoplasms (SMNs), a radiotherapy-associated complication in survivors of cancers, particularly pediatric cancers. SMN genomes are poorly characterized, and the influence of genetic background on genotoxin-induced mutations has not been examined. Using our mouse models of SMNs, we performed whole exome sequencing of neoplasms induced by fractionated IR in wild-type and Nf1 mutant mice. Using non-negative matrix factorization, we identified mutational signatures that did not segregate by genetic background or histology. Copy-number analysis revealed recurrent chromosomal alterations and differences in copy number that were background dependent. Pathway analysis identified enrichment of non-synonymous variants in genes responsible for cell assembly and organization, cell morphology, and cell function and maintenance. In this model system, ionizing radiation and Nf1 heterozygosity each exerted distinct influences on the mutational landscape.

Neurofibromatosis type 1 and malignancy in childhood

Neurofibromatosis type 1 (NF1) is an autosomal dominant hereditary neurocutaneous syndrome characterized by multi-system involvement and an increased incidence of both benign and malignant tumors. In this study, we evaluated the clinical presentation and prognosis of NF1 and malignancy. Between 1975 and 2013, 26 (5%) of the 473 patients with NF1 at our center developed non-neurofibroma neoplasms. The patient files of 26 subjects with tumors, other than optic glioma, were analyzed retrospectively to evaluate clinical features and treatment results. The age at diagnosis of NF1 ranged from 3 months to 16 years (median 5.5 years). The age range at tumor diagnosis was 1.5-33 years (median 8 years) in these 26 patients. The tumor histological subtypes included the following: 12 soft-tissue tumors (6 malignant peripheral nerve sheath tumors (MPNST), 5 rhabdomyosarcomas (RMS) and 1 malignant fibrous histiocytoma), 11 brain tumors (6 low-grade gliomas, 3 high-grade gliomas, and 2 medulloblastoma), 2 neuroblastomas and 1 non-Hodgkin's lymphoma. Twelve of 26 patients were alive at the time of the study. Although benign brain tumors with NF1 are more common, high-grade brain tumors also occur. Thus, careful and regular follow-up is crucial for early detection of malignancy in NF1 patients.

Anatomic and metabolic evaluation of peripheral nerve sheath tumors in patients with neurofibromatosis 1 using whole-body MRI and (18)F-FDG PET fusion

PURPOSE

Malignant peripheral nerve sheath tumors (MPNSTs) are the leading cause of death for patients with neurofibromatosis type 1 (NF1). Identification of hypermetabolic lesions on PET may help identify patients at risk for MPNST. The objective of this study was to identify clinical and MRI-derived variables that predicted increased metabolic activity of neurofibromas in NF1 patients as determined by PET.

METHODS

This prospective study included NF1 patients with neurofibromas of 5 cm in diameter or greater. All patients underwent whole-body MRI and F-FDG PET imaging. Tumor volume was calculated from the MR scans using a semiautomated 3-dimensional segmentation method. SUVmax's were calculated to quantify metabolic activity. Logistic regression analyses were performed to determine the relationship among SUVmax, tumor volume, location (extremity vs trunk), type (plexiform vs circumscribed), depth (superficial vs deep), patient age, and whole-body tumor burden.

RESULTS

A total of 311 neurofibromas were identified in 19 NF1 patients (mean age, 38 years; range, 19-58 years). One extreme outlier was excluded from analysis. Whole-body tumor volumes ranged from 0.4 to 1182.4 mL. Fifty of 310 tumors were FDG-avid on PET (16%) with median SUVmax of 2.2 (range, 0.4-9.6). Metabolic activity (SUVmax >2.5) correlated with tumor location (deep > superficial, trunk > extremity) in tumors with PET avidity.

CONCLUSIONS

In NF1 patients with neurofibromas of 5 cm or greater, the majority of internal tumors are not metabolically active on PET. Tumors with increased metabolic activity as defined by SUVmax greater than 2.5 (ie, suggestive of MPNST) are more likely to be deep and located within the trunk.

Neurofibromatosis type 1: a multidisciplinary approach to care

Neurofibromatosis type 1 is a relatively common inherited disorder. Patients have a high predisposition to develop both benign and malignant tumours. Although many manifestations of neurofibromatosis type 1 affect the nervous system, other organs and tissues can also be affected. Because of the varying features and clinical heterogeneity inherent to this disorder, patients can present to different medical and surgical specialists and, therefore, the association of clinical symptoms with neurofibromatosis type 1 might not be appreciated. Thus, for prompt diagnosis and to provide optimum care for patients with neurofibromatosis type 1, clinicians must be aware of the diverse clinical features of this disorder. We advocate a multidisciplinary approach to care, entailing a dedicated team of specialists throughout the lifetime of the patient. As our understanding of this disorder deepens through basic laboratory and clinical investigations, swift implementation of new effective treatments becomes feasible.