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Head and Neck Pathology Mar 2022The 5 edition of the World Health Organization (WHO) Classification of Head and Neck Tumours (2022) comes out only five years after the previous edition, however it...
The 5 edition of the World Health Organization (WHO) Classification of Head and Neck Tumours (2022) comes out only five years after the previous edition, however it presents important updates that run in parallel with the rapid progression involving the increasingly sophisticated molecular investigation and its interpretation, some of which already have therapy-related impact. This manuscript provides an overview of the leading changes introduced in the classification of Odontogenic and Maxillofacial Bone Tumours that encompasses cysts of the jaws, odontogenic tumours, giant cell lesions and bone cysts, and bone and cartilage tumours. This is the first edition that Essential and Desirable Diagnostic Features were added for each entity, so that the most important clinical, microscopic and/or radiologic features were encapsulated and briefly highlighted. Surgical ciliated cyst was added to the group of odontogenic cysts, adenoid ameloblastoma was a newly recognized benign epithelial odontogenic tumour, and segmental odontomaxillary dysplasia was introduced in the group of fibro-osseous tumours and dysplasia. In addition, rhabdomyosarcoma with TFCP2 rearrangement, was introduced into the group of malignant jawbone tumours. The unique genetic aberrations distinguish it from other types of rhabdomyosarcomas. On the other hand, melanotic neuroectodermal tumour of infancy and osteoid osteoma were deleted from the benign bone and cartilageneous tumours, as was the hematolymphoid tumour of solitary plasmacytoma of bone. We systematically reviewed each entity in this chapter and provided important updated findings for selected topics that can further aid in the diagnostic process for challenging cases, broaden insights on the logic of the present classification, and finally, emphasize the potential that some of the molecular results may have in the near future to set new treatment approaches.
Topics: Bone Neoplasms; DNA-Binding Proteins; Head and Neck Neoplasms; Humans; Odontogenic Cysts; Odontogenic Tumors; Transcription Factors; World Health Organization
PubMed: 35312978
DOI: 10.1007/s12105-021-01404-7 -
The New England Journal of Medicine Apr 2020No approved therapies exist for inoperable plexiform neurofibromas in patients with neurofibromatosis type 1.
BACKGROUND
No approved therapies exist for inoperable plexiform neurofibromas in patients with neurofibromatosis type 1.
METHODS
We conducted an open-label, phase 2 trial of selumetinib to determine the objective response rate among patients with plexiform neurofibromas and to assess clinical benefit. Children with neurofibromatosis type 1 and symptomatic inoperable plexiform neurofibromas received oral selumetinib twice daily at a dose of 25 mg per square meter of body-surface area on a continuous dosing schedule (28-day cycles). Volumetric magnetic resonance imaging and clinical outcome assessments (pain, quality of life, disfigurement, and function) were performed at least every four cycles. Children rated tumor pain intensity on a scale from 0 (no pain) to 10 (worst pain imaginable).
RESULTS
A total of 50 children (median age, 10.2 years; range, 3.5 to 17.4) were enrolled from August 2015 through August 2016. The most frequent neurofibroma-related symptoms were disfigurement (44 patients), motor dysfunction (33), and pain (26). A total of 35 patients (70%) had a confirmed partial response as of March 29, 2019, and 28 of these patients had a durable response (lasting ≥1 year). After 1 year of treatment, the mean decrease in child-reported tumor pain-intensity scores was 2 points, considered a clinically meaningful improvement. In addition, clinically meaningful improvements were seen in child-reported and parent-reported interference of pain in daily functioning (38% and 50%, respectively) and overall health-related quality of life (48% and 58%, respectively) as well as in functional outcomes of strength (56% of patients) and range of motion (38% of patients). Five patients discontinued treatment because of toxic effects possibly related to selumetinib, and 6 patients had disease progression. The most frequent toxic effects were nausea, vomiting, or diarrhea; an asymptomatic increase in the creatine phosphokinase level; acneiform rash; and paronychia.
CONCLUSIONS
In this phase 2 trial, most children with neurofibromatosis type 1 and inoperable plexiform neurofibromas had durable tumor shrinkage and clinical benefit from selumetinib. (Funded by the Intramural Research Program of the National Institutes of Health and others; ClinicalTrials.gov number, NCT01362803.).
Topics: Adolescent; Benzimidazoles; Child; Child, Preschool; Female; Humans; Male; Mitogen-Activated Protein Kinase Kinases; Nausea; Neurofibroma, Plexiform; Neurofibromatosis 1; Pain; Patient Reported Outcome Measures; Progression-Free Survival; Protein Kinase Inhibitors; Tumor Burden
PubMed: 32187457
DOI: 10.1056/NEJMoa1912735 -
Neuro-oncology Nov 2022Plexiform Neurofibromas (PN) are a common manifestation of the genetic disorder neurofibromatosis type 1 (NF1). These benign nerve sheath tumors often cause significant... (Review)
Review
Plexiform Neurofibromas (PN) are a common manifestation of the genetic disorder neurofibromatosis type 1 (NF1). These benign nerve sheath tumors often cause significant morbidity, with treatment options limited historically to surgery. There have been tremendous advances over the past two decades in our understanding of PN, and the recent regulatory approvals of the MEK inhibitor selumetinib are reshaping the landscape for PN management. At present, there is no agreed upon PN definition, diagnostic evaluation, surveillance strategy, or clear indications for when to initiate treatment and selection of treatment modality. In this review, we address these questions via consensus recommendations from a panel of multidisciplinary NF1 experts.
Topics: Humans; Neurofibroma, Plexiform; Neurofibromatosis 1; Nerve Sheath Neoplasms; Protein Kinase Inhibitors
PubMed: 35657359
DOI: 10.1093/neuonc/noac146 -
Neurosurgery Feb 2021Neoplasms of the peripheral nervous system represent a heterogenous group with a wide spectrum of morphological features and biological potential. They range from benign... (Review)
Review
Neoplasms of the peripheral nervous system represent a heterogenous group with a wide spectrum of morphological features and biological potential. They range from benign and curable by complete excision (schwannoma and soft tissue perineurioma) to benign but potentially aggressive at the local level (plexiform neurofibroma) to the highly malignant (malignant peripheral nerve sheath tumors [MPNST]). In this review, we discuss the diagnostic and pathologic features of common peripheral nerve sheath tumors, particularly those that may be encountered in the intracranial compartment or in the spine and paraspinal region. The discussion will cover schwannoma, neurofibroma, atypical neurofibromatous neoplasms of uncertain biological potential, intraneural and soft tissue perineurioma, hybrid nerve sheath tumors, MPNST, and the recently renamed enigmatic tumor, malignant melanotic nerve sheath tumor, formerly referred to as melanotic schwannoma. We also discuss the diagnostic relevance of these neoplasms to specific genetic and familial syndromes of nerve, including neurofibromatosis 1, neurofibromatosis 2, and schwannomatosis. In addition, we discuss updates in our understanding of the molecular alterations that represent key drivers of these neoplasms, including neurofibromatosis type 1 and type 2, SMARCB1, LZTR1, and PRKAR1A loss, as well as the acquisition of CDKN2A/B mutations and alterations in the polycomb repressor complex members (SUZ12 and EED) in the malignant progression to MPNST. In summary, this review covers practical aspects of pathologic diagnosis with updates relevant to neurosurgical practice.
Topics: Animals; Humans; Nerve Sheath Neoplasms; Neurilemmoma; Neurofibroma; Neurofibromatoses; Peripheral Nerves; Peripheral Nervous System Neoplasms; Skin Neoplasms; Transcription Factors
PubMed: 33588442
DOI: 10.1093/neuros/nyab021 -
Neuro-oncology Nov 2022The wide variety of clinical manifestations of the genetic syndrome neurofibromatosis type 1 (NF1) are driven by overactivation of the RAS pathway. Mitogen-activated... (Review)
Review
The wide variety of clinical manifestations of the genetic syndrome neurofibromatosis type 1 (NF1) are driven by overactivation of the RAS pathway. Mitogen-activated protein kinase kinase inhibitors (MEKi) block downstream targets of RAS. The recent regulatory approvals of the MEKi selumetinib for inoperable symptomatic plexiform neurofibromas in children with NF1 have made it the first medical therapy approved for this indication in the United States, the European Union, and elsewhere. Several recently published and ongoing clinical trials have demonstrated that MEKi may have potential benefits for a variety of other NF1 manifestations, and there is broad interest in the field regarding the appropriate clinical use of these agents. In this review, we present the current evidence regarding the use of existing MEKi for a variety of NF1-related manifestations, including tumor (neurofibromas, malignant peripheral nerve sheath tumors, low-grade glioma, and juvenile myelomonocytic leukemia) and non-tumor (bone, pain, and neurocognitive) manifestations. We discuss the potential utility of MEKi in related genetic conditions characterized by overactivation of the RAS pathway (RASopathies). In addition, we review practical treatment considerations for the use of MEKi as well as provide consensus recommendations regarding their clinical use from a panel of experts.
Topics: Child; Humans; Consensus; Mitogen-Activated Protein Kinase Kinases; Neurofibroma, Plexiform; Neurofibromatosis 1; Protein Kinase Inhibitors
PubMed: 35788692
DOI: 10.1093/neuonc/noac165 -
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 -
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 -
The Journal of Clinical Investigation Jan 2021Neurofibromatosis type 1 (NF1) is a common tumor predisposition syndrome caused by NF1 gene mutation, in which affected patients develop Schwann cell lineage peripheral...
Neurofibromatosis type 1 (NF1) is a common tumor predisposition syndrome caused by NF1 gene mutation, in which affected patients develop Schwann cell lineage peripheral nerve sheath tumors (neurofibromas). To investigate human neurofibroma pathogenesis, we differentiated a series of isogenic, patient-specific NF1-mutant human induced pluripotent stem cells (hiPSCs) into Schwannian lineage cells (SLCs). We found that, although WT and heterozygous NF1-mutant hiPSCs-SLCs did not form tumors following mouse sciatic nerve implantation, NF1-null SLCs formed bona fide neurofibromas with high levels of SOX10 expression. To confirm that SOX10+ SLCs contained the cells of origin for neurofibromas, both Nf1 alleles were inactivated in mouse Sox10+ cells, leading to classic nodular cutaneous and plexiform neurofibroma formation that completely recapitulated their human counterparts. Moreover, we discovered that NF1 loss impaired Schwann cell differentiation by inducing a persistent stem-like state to expand the pool of progenitors required to initiate tumor formation, indicating that, in addition to regulating MAPK-mediated cell growth, NF1 loss also altered Schwann cell differentiation to promote neurofibroma development. Taken together, we established a complementary humanized neurofibroma explant and, to our knowledge, first-in-kind genetically engineered nodular cutaneous neurofibroma mouse models that delineate neurofibroma pathogenesis amenable to future therapeutic target discovery and evaluation.
Topics: Animals; Cell Line; Humans; Induced Pluripotent Stem Cells; Mice; Mice, Nude; Mice, Transgenic; Mutation; Neoplasms, Experimental; Neurofibroma; Neurofibromin 1
PubMed: 33108355
DOI: 10.1172/JCI139807 -
JCI Insight Sep 2022To define alterations early in tumor formation, we studied nerve tumors in neurofibromatosis 1 (NF1), a tumor predisposition syndrome. Affected individuals develop...
To define alterations early in tumor formation, we studied nerve tumors in neurofibromatosis 1 (NF1), a tumor predisposition syndrome. Affected individuals develop neurofibromas, benign tumors driven by NF1 loss in Schwann cells (SCs). By comparing normal nerve cells to plexiform neurofibroma (PN) cells using single-cell and bulk RNA sequencing, we identified changes in 5 SC populations, including a de novo SC progenitor-like (SCP-like) population. Long after Nf1 loss, SC populations developed PN-specific expression of Dcn, Postn, and Cd74, with sustained expression of the injury response gene Postn and showed dramatic expansion of immune and stromal cell populations; in corresponding human PNs, the immune and stromal cells comprised 90% of cells. Comparisons between injury-related and tumor monocytes/macrophages support early monocyte recruitment and aberrant macrophage differentiation. Cross-species analysis verified each SC population and unique conserved patterns of predicted cell-cell communication in each SC population. This analysis identified PROS1-AXL, FGF-FGFR, and MIF-CD74 and its effector pathway NF-κB as deregulated in NF1 SC populations, including SCP-like cells predicted to influence other types of SCs, stromal cells, and/or immune cells in mouse and human. These findings highlight remarkable changes in multiple types of SCs and identify therapeutic targets for PN.
Topics: Animals; Humans; Mice; NF-kappa B; Neurofibroma, Plexiform; Neurofibromatosis 1; Schwann Cells; Tumor Microenvironment
PubMed: 36134665
DOI: 10.1172/jci.insight.154513 -
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