Did you mean: neurofibromatosis
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The Lancet. Neurology Aug 2014Neurofibromatosis type 1 is a relatively common inherited disorder. Patients have a high predisposition to develop both benign and malignant tumours. Although many... (Review)
Review
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.
Topics: Antineoplastic Agents; Combined Modality Therapy; Genetic Testing; Humans; Neurofibromatosis 1; Patient Care Team; Skin Neoplasms
PubMed: 25030515
DOI: 10.1016/S1474-4422(14)70063-8 -
Genetics in Medicine : Official Journal... Aug 2021By incorporating major developments in genetics, ophthalmology, dermatology, and neuroimaging, to revise the diagnostic criteria for neurofibromatosis type 1 (NF1) and...
PURPOSE
By incorporating major developments in genetics, ophthalmology, dermatology, and neuroimaging, to revise the diagnostic criteria for neurofibromatosis type 1 (NF1) and to establish diagnostic criteria for Legius syndrome (LGSS).
METHODS
We used a multistep process, beginning with a Delphi method involving global experts and subsequently involving non-NF experts, patients, and foundations/patient advocacy groups.
RESULTS
We reached consensus on the minimal clinical and genetic criteria for diagnosing and differentiating NF1 and LGSS, which have phenotypic overlap in young patients with pigmentary findings. Criteria for the mosaic forms of these conditions are also recommended.
CONCLUSION
The revised criteria for NF1 incorporate new clinical features and genetic testing, whereas the criteria for LGSS were created to differentiate the two conditions. It is likely that continued refinement of these new criteria will be necessary as investigators (1) study the diagnostic properties of the revised criteria, (2) reconsider criteria not included in this process, and (3) identify new clinical and other features of these conditions. For this reason, we propose an initiative to update periodically the diagnostic criteria for NF1 and LGSS.
Topics: Cafe-au-Lait Spots; Consensus; Genetic Testing; Humans; Neurofibromatosis 1
PubMed: 34012067
DOI: 10.1038/s41436-021-01170-5 -
La Clinica Terapeutica 2020To better understand the real prevalence of cutaneous manifestations, in Neurofibromatosis type 1. (Review)
Review
OBJECTIVE
To better understand the real prevalence of cutaneous manifestations, in Neurofibromatosis type 1.
MATERIALS AND METHODS
We reviewed all clinical charts of 1102 NF1 patients followed by February 1983 to February 2020 at the "Sapienza" University of Rome, Italy. NF1 patients are seen usually every year by a dermatologist.
RESULT
Café-au-lait macules were shown in 1063 patients (96.5%), axillary and inguinal freckling in 991 (90%) and neurofibromas in 861 (78.1%). Other skin manifestations included: lipoma (6.2%), nevus anemicus (3.9%), psoriasis (3.4%), spilus nevus (3.2%), juvenile xanthogranuloma (3.2%), vitiligo (2.3%), Becker's nevus (1.9%), melanoma (0.7%) and poliosis (0.5%).
CONCLUSION
Neurofibromatosis type 1 is a multisystem disorder primarily involving the skin and nervous system. The clinical manifestations are extremely variable even within a family. This study was performed to delineate the prevalence of cutaneous manifestations in NF1.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Child; Child, Preschool; Female; Humans; Italy; Male; Middle Aged; Neurofibromatosis 1; Prevalence; Skin Diseases; Young Adult
PubMed: 32901776
DOI: 10.7417/CT.2020.2242 -
Human Pathology Sep 2017Patients with neurofibromatosis 1 (NF1) develop multiple neurofibromas, with 8% to 15% of patients experiencing malignant peripheral nerve sheath tumor (MPNST) during... (Review)
Review
Histopathologic evaluation of atypical neurofibromatous tumors and their transformation into malignant peripheral nerve sheath tumor in patients with neurofibromatosis 1-a consensus overview.
Patients with neurofibromatosis 1 (NF1) develop multiple neurofibromas, with 8% to 15% of patients experiencing malignant peripheral nerve sheath tumor (MPNST) during their lifetime. Prediction of transformation, typically from plexiform neurofibroma, is clinically and histologically challenging. In this overview, after a consensus meeting in October 2016, we outline the histopathologic features and molecular mechanisms involved in the malignant transformation of neurofibromas. Nuclear atypia alone is generally insignificant. However, with atypia, loss of neurofibroma architecture, high cellularity, and/or mitotic activity >1/50 but <3/10 high-power fields, the findings are worrisome for malignancy. We propose the term "atypical neurofibromatous neoplasms of uncertain biologic potential (ANNUBP)" for lesions displaying at least 2 of these features. This diagnosis should prompt additional sampling, clinical correlation, and possibly, expert pathology consultation. Currently, such tumors are diagnosed inconsistently as atypical neurofibroma or low-grade MPNST. Most MPNSTs arising from neurofibromas are high-grade sarcomas and pose little diagnostic difficulty, although rare nonnecrotic tumors with 3-9 mitoses/10 high-power fields can be recognized as low-grade variants. Although neurofibromas contain numerous S100 protein/SOX10-positive Schwann cells and CD34-positive fibroblasts, both components are reduced or absent in MPNST. Loss of p16/CDKN2A expression, elevated Ki67 labeling, and extensive nuclear p53 positivity are also features of MPNST that can to some degree already occur in atypical neurofibromatous neoplasms of uncertain biologic potential. Complete loss of trimethylated histone 3 lysine 27 expression is potentially more reliable, being immunohistochemically detectable in about half of MPNSTs. Correlated clinicopathological, radiologic, and genetic studies should increase our understanding of malignant transformation in neurofibromas, hopefully improving diagnosis and treatment soon.
Topics: Biomarkers, Tumor; Biopsy; Cell Nucleus; Consensus; Disease Progression; Humans; Immunohistochemistry; Mitosis; Neoplasm Grading; Neurilemmoma; Neurofibromatosis 1; Predictive Value of Tests; Terminology as Topic
PubMed: 28551330
DOI: 10.1016/j.humpath.2017.05.010 -
Journal of Medical Genetics Feb 2007Neurofibromatosis 1 (NF1) is a common neurocutaneous condition with an autosomal dominant pattern of inheritance. The complications are diverse and disease expression... (Review)
Review
Neurofibromatosis 1 (NF1) is a common neurocutaneous condition with an autosomal dominant pattern of inheritance. The complications are diverse and disease expression varies, even within families. Progress in molecular biology and neuroimaging and the development of mouse models have helped to elucidate the aetiology of NF1 and its clinical manifestations. Furthermore, these advances have raised the prospect of therapeutic intervention for this complex and distressing disease. Members of the United Kingdom Neurofibromatosis Association Clinical Advisory Board collaborated to produce a consensus statement on the current guidelines for diagnosis and management of NF1. The proposals are based on published clinical studies and on the pooled knowledge of experts in neurofibromatosis with experience of providing multidisciplinary clinical and molecular services for NF1 patients. The consensus statement discusses the diagnostic criteria, major differential diagnoses, clinical manifestations and the present strategies for monitoring and management of NF1 complications.
Topics: Child; Child, Preschool; Humans; Incidence; Infant; Infant, Newborn; Mutation; Neurofibromatosis 1; Neurofibromin 1
PubMed: 17105749
DOI: 10.1136/jmg.2006.045906 -
Human Genomics Jun 2017Neurofibromatosis type 1 (NF1: Online Mendelian Inheritance in Man (OMIM) #162200) is an autosomal dominantly inherited tumour predisposition syndrome. Heritable... (Review)
Review
BACKGROUND
Neurofibromatosis type 1 (NF1: Online Mendelian Inheritance in Man (OMIM) #162200) is an autosomal dominantly inherited tumour predisposition syndrome. Heritable constitutional mutations in the NF1 gene result in dysregulation of the RAS/MAPK pathway and are causative of NF1. The major known function of the NF1 gene product neurofibromin is to downregulate RAS. NF1 exhibits variable clinical expression and is characterized by benign cutaneous lesions including neurofibromas and café-au-lait macules, as well as a predisposition to various types of malignancy, such as breast cancer and leukaemia. However, acquired somatic mutations in NF1 are also found in a wide variety of malignant neoplasms that are not associated with NF1.
MAIN BODY
Capitalizing upon the availability of next-generation sequencing data from cancer genomes and exomes, we review current knowledge of somatic NF1 mutations in a wide variety of tumours occurring at a number of different sites: breast, colorectum, urothelium, lung, ovary, skin, brain and neuroendocrine tissues, as well as leukaemias, in an attempt to understand their broader role and significance, and with a view ultimately to exploiting this in a diagnostic and therapeutic context.
CONCLUSION
As neurofibromin activity is a key to regulating the RAS/MAPK pathway, NF1 mutations are important in the acquisition of drug resistance, to BRAF, EGFR inhibitors, tamoxifen and retinoic acid in melanoma, lung and breast cancers and neuroblastoma. Other curiosities are observed, such as a high rate of somatic NF1 mutation in cutaneous melanoma, lung cancer, ovarian carcinoma and glioblastoma which are not usually associated with neurofibromatosis type 1. Somatic NF1 mutations may be critical drivers in multiple cancers. The mutational landscape of somatic NF1 mutations should provide novel insights into our understanding of the pathophysiology of cancer. The identification of high frequency of somatic NF1 mutations in sporadic tumours indicates that neurofibromin is likely to play a critical role in development, far beyond that evident in the tumour predisposition syndrome NF1.
Topics: Genes, Neurofibromatosis 1; Humans; Mutation; Neoplasms; Neurofibromatosis 1
PubMed: 28637487
DOI: 10.1186/s40246-017-0109-3 -
Acta Neuropathologica Apr 2020Neurofibromatosis 1 (NF1) is an autosomal dominant genetic disorder that presents with variable phenotypes as a result of mutations in the neurofibromatosis type 1 (NF1)... (Review)
Review
Neurofibromatosis 1 (NF1) is an autosomal dominant genetic disorder that presents with variable phenotypes as a result of mutations in the neurofibromatosis type 1 (NF1) gene and subsequently, abnormal function of the protein product, neurofibromin. Patients with NF1 are at increased risk for central nervous system (CNS) manifestations including structural, functional, and neoplastic disease. The mechanisms underlying the varied manifestations of NF1 are incompletely understood, but the loss of functional neurofibromin, resulting in sustained activation of the oncoprotein RAS, is responsible for tumorigenesis throughout the body, including the CNS. Much of our understanding of NF1-related CNS manifestations is from a combination of data from animal models and natural history studies of people with NF1 and CNS disease. Data from animal models suggest the importance of both Nf1 mutations and somatic genetic alterations, such as Tp53 loss, for development of neoplasms, as well as the role of the timing of the acquisition of such alterations on the variability of CNS manifestations. A variety of non-neoplastic structural (macrocephaly, hydrocephalus, aqueductal stenosis, and vasculopathy) and functional (epilepsy, impaired cognition, attention deficits, and autism spectrum disorder) abnormalities occur with variable frequency in individuals with NF1. In addition, there is increasing evidence that similar appearing CNS neoplasms in people with and without the NF1 syndrome are due to distinct oncogenic pathways. Gliomas in people with NF1 show alterations in the RAS/MAPK pathway, generally in the absence of BRAF alterations (common to sporadic pilocytic astrocytomas) or IDH or histone H3 mutations (common to diffuse gliomas subsets). A subset of low-grade astrocytomas in these patients remain difficult to classify using standard criteria, and occasionally demonstrate morphologic features resembling subependymal giant cell astrocytomas that afflict patients with tuberous sclerosis complex ("SEGA-like astrocytomas"). There is also emerging evidence that NF1-associated high-grade astrocytomas have frequent co-existing alterations such as ATRX mutations and an alternative lengthening of telomeres (ALT) phenotype responsible for unique biologic properties. Ongoing efforts are seeking to improve diagnostic accuracy for CNS neoplasms in the setting of NF1 versus sporadic tumors. In addition, MEK inhibitors, which act on the RAS/MAPK pathway, continue to be studied as rational targets for the treatment of NF1-associated tumors, including CNS tumors.
Topics: Animals; Central Nervous System Diseases; Genetic Predisposition to Disease; Humans; Neurofibromatosis 1
PubMed: 30963251
DOI: 10.1007/s00401-019-02002-2 -
Genetics in Medicine : Official Journal... Jul 2018This practice resource is designed primarily as an educational resource for medical geneticists and other clinicians to help them provide quality medical services....
DISCLAIMER
This practice resource is designed primarily as an educational resource for medical geneticists and other clinicians to help them provide quality medical services. Adherence to this practice resource is completely voluntary and does not necessarily assure a successful medical outcome. This practice resource should not be considered inclusive of all proper procedures and tests or exclusive of other procedures and tests that are reasonably directed to obtaining the same results. In determining the propriety of any specific procedure or test, the clinician should apply his or her own professional judgment to the specific clinical circumstances presented by the individual patient or specimen. Clinicians are encouraged to document the reasons for the use of a particular procedure or test, whether or not it is in conformance with this practice resource. Clinicians also are advised to take notice of the date this practice resource was adopted, and to consider other medical and scientific information that becomes available after that date. It also would be prudent to consider whether intellectual property interests may restrict the performance of certain tests and other procedures.
PURPOSE
Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder that is caused by a heterozygous loss-of-function variant in the tumor suppressor gene NF1; it affects ~1/1,900-1/3,500 people worldwide. The disorder is associated with an 8-15-year reduction in average life expectancy in both men and women, primarily due to malignant neoplasms and cardiovascular causes.
METHODS
A work group of experts sought to determine the prevalence, morbidity and mortality, and available treatments of common and emerging NF1-related clinical problems in adults. Work-group members identified peer-reviewed publications from PubMed. Publications derived from populations and multi-institution cohorts were prioritized. Recommendations for management arose by consensus from this literature and the collective expertise of the authors.
RESULTS
Malignant peripheral nerve sheath tumor (MPNST), breast cancer, cutaneous neurofibromas, and significant psychiatric and neurologic diagnoses are common problems in patients with NF1.
CONCLUSION
Patient education and sensitization to worrisome signs and symptoms such as progressive severe pain (MPNST), changes in tumor volume (MPNST), new, unexplained neurologic symptoms (MPNST, brain tumors), and diaphoresis/palpitations (pheochromocytoma) are important. Although many issues in adults with NF1 can be managed by an internist or family physician, we strongly encourage evaluation by, and care coordination with, a specialized NF1 clinic.
Topics: Genetic Testing; Genetics, Medical; Genomics; Humans; Neurofibromatosis 1; Neurofibromin 1; United States
PubMed: 30006586
DOI: 10.1038/gim.2018.28 -
BMC Cancer Jun 2023Neurofibromatosis type 1 (NF1), the most common tumor predisposition syndrome, occurs when NF1 gene variants result in loss of neurofibromin, a negative regulator of RAS... (Review)
Review
Neurofibromatosis type 1 (NF1), the most common tumor predisposition syndrome, occurs when NF1 gene variants result in loss of neurofibromin, a negative regulator of RAS activity. Plexiform neurofibromas (PN) are peripheral nerve sheath tumors that develop in patients with NF1 and are associated with substantial morbidity and for which, until recently, the only treatment was surgical resection. However, surgery carries several risks and a proportion of PN are considered inoperable. Understanding the genetic underpinnings of PN led to the investigation of targeted therapies as medical treatment options, and the MEK1/2 inhibitor selumetinib has shown promising efficacy in pediatric patients with NF1 and symptomatic, inoperable PN. In a phase I/II trial, most children (approximately 70%) achieved reduction in tumor volume accompanied by improvements in patient-reported outcomes (decreased tumor-related pain and improvements in quality of life, strength, and range of motion). Selumetinib is currently the only licensed medical therapy indicated for use in pediatric patients with symptomatic, inoperable NF1-PN, with approval based on the results of this pivotal clinical study. Several other MEK inhibitors (binimetinib, mirdametinib, trametinib) and the tyrosine kinase inhibitor cabozantinib are also being investigated as medical therapies for NF1-PN. Careful consideration of multiple aspects of both disease and treatments is vital to reduce morbidity and improve outcomes in patients with this complex and heterogeneous disease, and clinicians should be fully aware of the risks and benefits of available treatments. There is no single treatment pathway for patients with NF1-PN; surgery, watchful waiting, and/or medical treatment are options. Treatment should be individualized based on recommendations from a multidisciplinary team, considering the size and location of PN, effects on adjacent tissues, and patient and family preferences. This review outlines the treatment strategies currently available for patients with NF1-PN and the evidence supporting the use of MEK inhibitors, and discusses key considerations in clinical decision-making.
Topics: Child; Humans; Neurofibromatosis 1; Neurofibroma, Plexiform; Quality of Life; Protein Kinase Inhibitors; Mitogen-Activated Protein Kinase Kinases
PubMed: 37328781
DOI: 10.1186/s12885-023-10996-y -
ESMO Open Aug 2021Neurofibromatosis type 1 (NF1) is a genetic disorder that carries a higher risk of tumor development. Plexiform neurofibromas (PNs) are present in 50% of NF1 and cause... (Review)
Review
Neurofibromatosis type 1 (NF1) is a genetic disorder that carries a higher risk of tumor development. Plexiform neurofibromas (PNs) are present in 50% of NF1 and cause significant morbidity when surgery is not feasible. Systemic therapies had not succeeded to reduce PN tumor volume until 2016 when the first trial with an MAPK/extracellular-signal-regulated kinase (MEK) inhibitor was published. We performed a systematic research on novel targeted therapies for patients with NF1 and PNs in PubMed, EMBASE, and conference abstracts with the last update in February 2021. Since 2016, seven trials have reported positive results with MEK inhibitors and other molecular targeted therapies (cabozantinib). Selumetinib has shown an overall response rate of 68% in children with NF1 and symptomatic inoperable PNs, and was associated with pain improvement and a manageable adverse events profile. This led to Food and Drug Administration (FDA) approval of selumetinib in May 2020. Recently, cabozantinib and mirdametinib have also proven their efficacy in adult population. Other MEK inhibitors such as trametinib and binimetinib have also communicated promising preliminary results. Ongoing trials in different populations and with intermittent dosing strategies are underway.
Topics: Adult; Child; Humans; Molecular Targeted Therapy; Neurofibroma, Plexiform; Neurofibromatosis 1; Protein Kinase Inhibitors; Tumor Burden
PubMed: 34388689
DOI: 10.1016/j.esmoop.2021.100223