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Journal of Oral and Maxillofacial... 2021Plexiform neurofibroma (PNF) is a rare form of neurofibromatosis type 1 which is rarely seen isolated. This generally spreads along the peripheral nerve and may affect...
Plexiform neurofibroma (PNF) is a rare form of neurofibromatosis type 1 which is rarely seen isolated. This generally spreads along the peripheral nerve and may affect some nervous rami. This is a poorly circumscribed and locally invasive tumor. About 21% of patients with NF-I are affected with PNFs. The nevus of Ota also called oculodermal melanocytosis is a macular discoloration of the face. It is most commonly found in the Japanese and very rare in the Indian subcontinent. It is unilateral oculodermal melanosis along the first two branches of the trigeminal nerve. We hereby present a very rare case of occurrence of isolated PNF (not associated with neurofibromatosis type 1) along with nevus of ota of the left side of the face in a 28-year-old female with thorough radiographic work up.
PubMed: 34703146
DOI: 10.4103/0973-029X.325263 -
American Journal of Translational... 2022Neurofibromatosis type 1 (NF1) predisposes to the development of dermal and plexiform neurofibromas and serum of NF1 patients stimulates neurofibroma proliferation in...
Neurofibromatosis type 1 (NF1) predisposes to the development of dermal and plexiform neurofibromas and serum of NF1 patients stimulates neurofibroma proliferation in vitro. This study aimed to determine whether, in NF1 patients, serum levels of midkine (MK) and fibroblast growth factor 2 (FGF2) were associated with the number and/or type of neurofibromas. In addition, their concentrations were correlated with serum levels of dehydroepiandrosterone sulfate (DHEAS), a neurosteroid secreted by the peripheral nervous system. We performed a case control-study and measured, by ELISA assay, serum concentrations of MK, FGF2, and DHEAS in 20 NF1 patients and 30 controls. We found increased serum levels of MK and FGF2 in NF1 patients between 30 and 50 years old. Their concentrations were significantly higher in NF1 patients with plexiform neurofibromas than in controls (P=0.003 for MK and P=0.008 for FGF2). As an underlying hormonal regulation was suspected, DHEAS serum levels were measured but no difference was observed between patients and controls. We also observed a strong association between MK and FGF2 levels (P=0.0001) in NF1 patients and controls. In conclusion, we point out MK and FGF2 as biomarkers for plexiform neurofibroma in NF1 patients. As both growth factors are estrogen-responsive genes and neurofibromin is a co-repressor of estrogen receptor alpha activity, we suggest that the increased serum levels of MK and FGF2 observed in NF1 patients might be due to estradiol hypersensitivity.
PubMed: 35702135
DOI: No ID Found -
Cureus Mar 2022Neurofibromatosis type one (NF-1) is an autosomal dominant neurocutaneous disorder also known as Von Recklinghausen disease. Plexiform neurofibroma is a rare kind of...
Neurofibromatosis type one (NF-1) is an autosomal dominant neurocutaneous disorder also known as Von Recklinghausen disease. Plexiform neurofibroma is a rare kind of NF-1 where the neurofibroma originates from nerve sheath cells or subcutaneous peripheral nerves. It is pathognomonic of NF-1, and isolated occurrence is relatively rare. We reported three cases of solitary plexiform neurofibromas with an unusual presentation. We have two cases of spontaneous bleeding isolated plexiform neurofibroma that have never been reported in the literature. Neither one of them showed signs and symptoms associated with the neurofibromatosis spectrum. This unusual presentation poses substantial challenges in diagnosis and management.
PubMed: 35308189
DOI: 10.7759/cureus.23141 -
Cancers May 2023Limited therapies exist for neurofibromatosis type 1 (NF1)-associated plexiform neurofibroma (PN). For this reason, the activity of vinblastine (VBL) and methotrexate...
Limited therapies exist for neurofibromatosis type 1 (NF1)-associated plexiform neurofibroma (PN). For this reason, the activity of vinblastine (VBL) and methotrexate (MTX) was evaluated in children and young adults with NF1 and PN. Patients ≤ 25 years of age with progressive and/or inoperable NF1-PN received VBL 6 mg/m and MTX 30 mg/m weekly for 26 weeks, followed by every 2 weeks for 26 weeks. Objective response rate was the primary endpoint. Of 25 participants enrolled, 23 were evaluable. The median age of participants was 6.6 years (range 0.3-20.7). The most frequent toxicities were neutropenia and elevation of transaminases. On two-dimensional (2D) imaging, 20 participants (87%) had stable tumor, with a median time to progression of 41.5 months (95% confidence interval 16.9, 64.9). Two of eight participants (25%) with airway involvement demonstrated functional improvements including decreased positive pressure requirements and apnea-hypopnea index. A post hoc three-dimensional (3D) analysis of PN volumes was completed on 15 participants with amenable imaging; 7 participants (46%) had progressive disease on or by the end of therapy. VBL/MTX was well-tolerated but did not result in objective volumetric response. Furthermore, 3D volumetric analysis highlighted the lack of sensitivity of 2D imaging for PN response evaluation.
PubMed: 37174087
DOI: 10.3390/cancers15092621 -
Annual Review of Pathology 2012Neurofibromatosis type 1 (NF1) is a genetic disease that results from either heritable or spontaneous autosomal dominant mutations in the NF1 gene. A second-hit mutation... (Review)
Review
Neurofibromatosis type 1 (NF1) is a genetic disease that results from either heritable or spontaneous autosomal dominant mutations in the NF1 gene. A second-hit mutation precedes the predominant NF1 neoplasms, which include myeloid leukemia, optic glioma, and plexiform neurofibroma. Despite this requisite NF1 loss of heterozygosity in the tumor cell of origin, nontumorigenic cells contribute to both generalized and specific disease manifestations. In mouse models of plexiform neurofibroma formation, Nf1 haploinsufficient mast cells promote inflammation, accelerating tumor formation and growth. These recruited mast cells, hematopoietic effector cells long known to permeate neurofibroma tissue, mediate key mitogenic signals that contribute to vascular ingrowth, collagen deposition, and tumor growth. Thus, the plexiform neurofibroma microenvironment involves a tumor/stromal interaction with the hematopoietic system that depends, at the molecular level, on a stem cell factor/c-kit-mediated signaling axis. These observations parallel findings in other NF1 disease manifestations and are clearly relevant to medical management of these neurofibromas.
Topics: Animals; Antineoplastic Agents; Benzamides; Hematopoietic System; Humans; Imatinib Mesylate; Mast Cells; Neurofibroma, Plexiform; Neurofibromatosis 1; Neurofibromin 1; Piperazines; Proto-Oncogene Proteins c-kit; Pyrimidines; Signal Transduction; Stem Cell Factor; Tumor Microenvironment
PubMed: 22077553
DOI: 10.1146/annurev-pathol-011811-132441 -
Cancers Dec 2023: Neurofibromatosis type 1 (NF1) is a genetic disorder characterized by heterozygous germline gene mutations that predispose patients to developing plexiform...
: Neurofibromatosis type 1 (NF1) is a genetic disorder characterized by heterozygous germline gene mutations that predispose patients to developing plexiform neurofibromas, which are benign but often disfiguring tumors of the peripheral nerve sheath induced by loss of heterozygosity at the locus. These can progress to malignant peripheral nerve sheath tumors (MPNSTs). There are no approved drug treatments for adults with NF1-related inoperable plexiform neurofibromas, and only one drug (selumetinib), which is an FDA-approved targeted therapy for the treatment of symptomatic pediatric plexiform neurofibromas, highlighting the need for additional drug screening and development. In high-throughput screening, the effectiveness of drugs against cell lines is often assessed by measuring in vitro potency (AC50) or the area under the curve (AUC). However, the variability of dose-response curves across drugs and cell lines and the frequency of partial effectiveness suggest that these measures alone fail to provide a full picture of overall efficacy. : Using concentration-response data, we combined response effectiveness (EFF) and potency (AC50) into (a) a score characterizing the effect of a compound on a single cell line, = log[EFF/AC50], and (b) a relative score, , characterizing the relative difference between a reference (e.g., non-tumor) and test (tumor) cell line. was applied to data from high-throughput screening (HTS) of a drug panel tested on tumor cells, using immortalized non-tumor cells as a reference. : We identified drugs with sensitivity, targeting expected pathways, such as MAPK-ERK and PI3K-AKT, as well as serotonin-related targets, among others. The technique used here, in tandem with a supplemental web tool, simplifies HTS analysis and may provide a springboard for further investigations into drug response in NF1-related cancers. The tool may also prove useful for drug development in a variety of other cancers.
PubMed: 38136356
DOI: 10.3390/cancers15245811 -
Cancers Sep 2022Neurofibromatosis type 1 (NF1), a genetic tumor predisposition syndrome that affects about 1 in 3000 newborns, is caused by mutations in the gene and subsequent... (Review)
Review
BACKGROUND
Neurofibromatosis type 1 (NF1), a genetic tumor predisposition syndrome that affects about 1 in 3000 newborns, is caused by mutations in the gene and subsequent inactivation of its encoded neurofibromin. Neurofibromin is a tumor suppressor protein involved in the downregulation of Ras signaling. Despite a diverse clinical spectrum, one of several hallmarks of NF1 is a peripheral nerve sheath tumor (PNST), which comprises mixed nervous and fibrous components. The distinct spatiotemporal characteristics of plexiform and cutaneous neurofibromas have prompted hypotheses about the origin and developmental features of these tumors, involving various cellular transition processes.
METHODS
We retrieved published literature from PubMed, EMBASE, and Web of Science up to 21 June 2022 and searched references cited in the selected studies to identify other relevant papers. Original articles reporting the pathogenesis of PNSTs during development were included in this review. We highlighted the Schwann cell (SC) lineage shift to better present the evolution of its corresponding cellular origin hypothesis and its important effects on the progression and malignant transformation of neurofibromas.
CONCLUSIONS
In this review, we summarized the vast array of evidence obtained on the full range of neurofibroma development based on cellular and molecular pathogenesis. By integrating findings relating to tumor formation, growth, and malignancy, we hope to reveal the role of SC lineage shift as well as the combined impact of additional determinants in the natural history of PNSTs.
PubMed: 36139671
DOI: 10.3390/cancers14184513 -
Neuro-oncology Advances Jul 2020Neurofibromatosis type I (NF1) is a debilitating inherited tumor syndrome affecting around 1 in 3000 people. Patients present with a variety of tumors caused by... (Review)
Review
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 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.
PubMed: 32642729
DOI: 10.1093/noajnl/vdz044 -
The Journal of Clinical Investigation Jun 2023Neurofibromatosis type 1 (NF1) is one of the most common tumor-predisposing genetic disorders. Neurofibromas are NF1-associated benign tumors. A hallmark feature of...
Neurofibromatosis type 1 (NF1) is one of the most common tumor-predisposing genetic disorders. Neurofibromas are NF1-associated benign tumors. A hallmark feature of neurofibromas is an abundant collagen-rich extracellular matrix (ECM) that constitutes more than 50% of the tumor dry weight. However, little is known about the mechanism underlying ECM deposition during neurofibroma development and treatment response. We performed a systematic investigation of ECM enrichment during plexiform neurofibroma (pNF) development and identified basement membrane (BM) proteins, rather than major collagen isoforms, as the most upregulated ECM component. Following MEK inhibitor treatment, the ECM profile displayed an overall downregulation signature, suggesting ECM reduction as a therapeutic benefit of MEK inhibition. Through these proteomic studies, TGF-β1 signaling was identified as playing a role in ECM dynamics. Indeed, TGF-β1 overexpression promoted pNF progression in vivo. Furthermore, by integrating single-cell RNA sequencing, we found that immune cells including macrophages and T cells produce TGF-β1 to induce Schwann cells to produce and deposit BM proteins for ECM remodeling. Following Nf1 loss, neoplastic Schwann cells further increased BM protein deposition in response to TGF-β1. Our data delineate the regulation governing ECM dynamics in pNF and suggest that BM proteins could serve as biomarkers for disease diagnosis and treatment response.
Topics: Humans; Neurofibromatosis 1; Transforming Growth Factor beta1; Membrane Proteins; Proteomics; Neurofibroma; Protein Kinase Inhibitors; Collagen; Basement Membrane; Extracellular Matrix; Mitogen-Activated Protein Kinase Kinases; Schwann Cells
PubMed: 37140985
DOI: 10.1172/JCI168227 -
Journal of Pediatric Genetics Dec 2017The most frequent genital presentation of neurofibromatosis in females is clitoromegaly. We report a case of a 5-year-old girl with neurofibromatosis type 1 with...
The most frequent genital presentation of neurofibromatosis in females is clitoromegaly. We report a case of a 5-year-old girl with neurofibromatosis type 1 with clitoral plexiform neurofibromatosis. Clitoroplasty was done, and the histopathology confirmed the diagnosis. Though rare, plexiform neurofibroma of clitoris should always be considered as a differential diagnosis in children with clitoromegaly before embarking on detailed investigations.
PubMed: 29142769
DOI: 10.1055/s-0037-1602789