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Brain Pathology (Zurich, Switzerland) Apr 2014Schwannomas may occur spontaneously, or in the context of a familial tumor syndrome such as neurofibromatosis type 2 (NF2), schwannomatosis and Carney's complex.... (Review)
Review
Schwannomas may occur spontaneously, or in the context of a familial tumor syndrome such as neurofibromatosis type 2 (NF2), schwannomatosis and Carney's complex. Schwannomas have a variety of morphological appearances, but they behave as World Health Organization (WHO) grade I tumors, and only very rarely undergo malignant transformation. Central to the pathogenesis of these tumors is loss of function of merlin, either by direct genetic change involving the NF2 gene on chromosome 22 or secondarily to merlin inactivation. The genetic pathways and morphological features of schwannomas associated with different genetic syndromes will be discussed. Merlin has multiple functions, including within the nucleus and at the cell membrane, and this review summarizes our current understanding of the mechanisms by which merlin loss is involved in schwannoma pathogenesis, highlighting potential areas for therapeutic intervention.
Topics: Animals; Brain Neoplasms; Carney Complex; Humans; Neurilemmoma; Neurofibromatosis 2
PubMed: 24450866
DOI: 10.1111/bpa.12125 -
Nature Genetics Feb 2014Constitutional SMARCB1 mutations at 22q11.23 have been found in ∼50% of familial and <10% of sporadic schwannomatosis cases. We sequenced highly conserved regions...
Constitutional SMARCB1 mutations at 22q11.23 have been found in ∼50% of familial and <10% of sporadic schwannomatosis cases. We sequenced highly conserved regions along 22q from eight individuals with schwannomatosis whose schwannomas involved somatic loss of one copy of 22q, encompassing SMARCB1 and NF2, with a different somatic mutation of the other NF2 allele in every schwannoma but no mutation of the remaining SMARCB1 allele in blood and tumor samples. LZTR1 germline mutations were identified in seven of the eight cases. LZTR1 sequencing in 12 further cases with the same molecular signature identified 9 additional germline mutations. Loss of heterozygosity with retention of an LZTR1 mutation was present in all 25 schwannomas studied. Mutations segregated with disease in all available affected first-degree relatives, although four asymptomatic parents also carried an LZTR1 mutation. Our findings identify LZTR1 as a gene predisposing to an autosomal dominant inherited disorder of multiple schwannomas in ∼80% of 22q-related schwannomatosis cases lacking mutation in SMARCB1.
Topics: Base Sequence; Chromosomal Proteins, Non-Histone; Chromosomes, Human, Pair 22; DNA, Complementary; DNA-Binding Proteins; Gene Components; Genes, Dominant; Genetic Predisposition to Disease; Germ-Line Mutation; Humans; Loss of Heterozygosity; Microsatellite Repeats; Models, Molecular; Molecular Sequence Data; Neurilemmoma; Neurofibromatosis 2; Pedigree; Protein Conformation; SMARCB1 Protein; Sequence Analysis, DNA; Transcription Factors
PubMed: 24362817
DOI: 10.1038/ng.2855 -
Cureus Mar 2016Neurofibromas and schwannomas are common lesions that may be idiopathic or may occur in association with neural crest genetic syndromes such as neurofibromatosis type 1,...
Neurofibromas and schwannomas are common lesions that may be idiopathic or may occur in association with neural crest genetic syndromes such as neurofibromatosis type 1, neurofibromatosis type 2, and schwannomatosis. A hybrid tumor that contains pathological characteristics of both neurofibroma and schwannoma has been described as a rare entity. We present the clinical, radiographic, and pathological findings of such a case.
PubMed: 27158577
DOI: 10.7759/cureus.548 -
Children (Basel, Switzerland) Jan 2022The three types of neurofibromatosis, namely type 1, type 2, and schwannomatosis, are generally associated with various benign tumors affecting the skin and the nervous... (Review)
Review
The three types of neurofibromatosis, namely type 1, type 2, and schwannomatosis, are generally associated with various benign tumors affecting the skin and the nervous system. On rare occasions, especially in patients with neurofibromatosis type 1 (NF1), malignant neoplasms may also be present, several of them possessing a more aggressive course than in individuals without this syndrome. As such, a clear delineation between the three variants of neurofibromatosis is crucial to establish the correct diagnosis and management, as well as predict the neoplasm-related outcomes. Neurofibromin, the principal product of the NF1 gene, is a potent inhibitor of cellular proliferation, having been linked to several key signaling pathways involved in tumor growth. Therefore, it may provide a useful therapeutic target for tumor management in these patients. In this article, we want to present the association between deficiency of neurofibromin and the consequences of the lack of this protein leading to different kinds of malignant tumors. The therapy is still uncertain and most therapeutic options are in development or clinical trials.
PubMed: 35053664
DOI: 10.3390/children9010040 -
The Open Neuroimaging Journal 2011We describe a case of schwannomatosis presenting as radicular pain and numbness in multiple radicular nerve distributions. There were multiple peripheral nerve tumors...
We describe a case of schwannomatosis presenting as radicular pain and numbness in multiple radicular nerve distributions. There were multiple peripheral nerve tumors detected by magnetic resonance imaging (MRI) at the left vestibular nerve, cauda equina, right radial nerve, thoracic paraspinal nerve, and brachial plexi. Several resected tumors have features of schwannomas, including hypercellular Antoni A areas, hypocellular Antoni B areas, Verocay bodies, and hyalinized blood vessels. The specimens are also positive for immunohistochemical staining for INI1 with diffuse nuclear staining. The findings are consistent with sporadic form of schwannomatosis. This case highlights the importance of using MRI and INI1 immunohistochemistry to differentiate familial schwannomatosis, neurofibromatosis 2 (NF2)-associated schwannomatosis, and sporadic schwannomatosis.
PubMed: 21643503
DOI: 10.2174/1874440001105010009 -
Taiwan Journal of Ophthalmology 2020Hybrid peripheral nerve sheath tumors (HPNST) are recently classified tumors from the World Health Organization Classification of soft tissue tumors that display... (Review)
Review
Hybrid peripheral nerve sheath tumors (HPNST) are recently classified tumors from the World Health Organization Classification of soft tissue tumors that display combined features of more than one peripheral nerve sheath tumor. Acknowledgment is important because of its association with the development of neurofibromatosis type 1, type 2, and schwannomatosis. Orbital involvement is rare and only six cases of HPNST have been documented on literature. This article serves to review the pathophysiology, clinical manifestation, diagnosis, treatment, and prognosis of this infrequent but important orbital tumor.
PubMed: 33110748
DOI: 10.4103/tjo.tjo_28_20 -
Pediatric Neurology Sep 2022The neurofibromatoses comprise three different genetic conditions causing considerable morbidity and mortality: neurofibromatosis type 1 (NF1), neurofibromatosis type 2... (Review)
Review
INTRODUCTION
The neurofibromatoses comprise three different genetic conditions causing considerable morbidity and mortality: neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2), and schwannomatosis (SWN). This review summarizes recent and ongoing clinical trials involving patients with neurofibromatoses to better understand the current state of clinical trial research centered around these conditions and inform areas of need.
METHODS
A search was conducted using the Cochrane Central Register of Controlled Trials and clinicaltrials.gov databases. Inclusion and exclusion criteria were designed to identify clinical trials focused on patients with NF1, NF2, or SWN completed in or after 2010 and in process as of December 31, 2021. Information was collected using standardized guidelines.
RESULTS
A total of 134 clinical trials were included, with 75 (56%) completed and 59 (44%) in process. For completed trials, 74% (n = 56) involved patients with NF1, and of those based on specific tumors (n = 26, 46%), the majority focused on plexiform neurofibromas (PNs) (n = 12, 46%). For ongoing trials, 79% (n = 47) involve patients with NF1, and of those based on specific tumors (n = 29, 61%), the majority are focused on PNs (n = 13, 45%).
CONCLUSION
Both recent and ongoing clinical trials have primarily focused on patients with NF1 and the treatment of PNs. This research has led to the first FDA-approved drug for NF1-PN and has changed management of these tumors, allowing for systemic therapy rather than reliance on only a surgical modality. Trials evaluating comorbid psychiatric conditions and quality of life among patients with any of the neurofibromatoses appear less common. These areas may warrant focus in future studies to improve clinical management.
Topics: Humans; Neurilemmoma; Neurofibroma, Plexiform; Neurofibromatoses; Neurofibromatosis 1; Neurofibromatosis 2; Quality of Life; Skin Neoplasms
PubMed: 35759947
DOI: 10.1016/j.pediatrneurol.2022.06.003 -
Clinical Trials (London, England) Feb 2024Numerous successful gene-targeted therapies are arising for the treatment of a variety of rare diseases. At the same time, current treatment options for...
Numerous successful gene-targeted therapies are arising for the treatment of a variety of rare diseases. At the same time, current treatment options for neurofibromatosis 1 and schwannomatosis are limited and do not directly address loss of gene/protein function. In addition, treatments have mostly focused on symptomatic tumors, but have failed to address multisystem involvement in these conditions. Gene-targeted therapies hold promise to address these limitations. However, despite intense interest over decades, multiple preclinical and clinical issues need to be resolved before they become a reality. The optimal approaches to gene-, mRNA-, or protein restoration and to delivery to the appropriate cell types remain elusive. Preclinical models that recapitulate manifestations of neurofibromatosis 1 and schwannomatosis need to be refined. The development of validated assays for measuring neurofibromin and merlin activity in animal and human tissues will be critical for early-stage trials, as will the selection of appropriate patients, based on their individual genotypes and risk/benefit balance. Once the safety of gene-targeted therapy for symptomatic tumors has been established, the possibility of addressing a wide range of symptoms, including non-tumor manifestations, should be explored. As preclinical efforts are underway, it will be essential to educate both clinicians and those affected by neurofibromatosis 1/schwannomatosis about the risks and benefits of gene-targeted therapy for these conditions.
Topics: Animals; Humans; Neurofibromatosis 1; Neurofibromatosis 2; Neurofibromatoses; Neurilemmoma; Skin Neoplasms
PubMed: 37937606
DOI: 10.1177/17407745231207970