Malignancy in neurofibromatosis type 1

Early Detection of Malignant and Premalignant Peripheral Nerve Tumors Using Cell-Free DNA Fragmentomics

PURPOSE

Early detection of neurofibromatosis type 1 (NF1)-associated peripheral nerve sheath tumors (PNST) informs clinical decision-making, enabling early definitive treatment and potentially averting deadly outcomes. In this study, we describe a cell-free DNA (cfDNA) fragmentomic approach that distinguishes nonmalignant, premalignant, and malignant forms of PNST in the cancer predisposition syndrome, NF1.

EXPERIMENTAL DESIGN

cfDNA was isolated from plasma samples of a novel cohort of 101 patients with NF1 and 21 healthy controls and underwent whole-genome sequencing. We investigated diagnosis-specific signatures of copy-number alterations with in silico size selection as well as fragment profiles. Fragmentomics were analyzed using complementary feature types: bin-wise fragment size ratios, end motifs, and fragment non-negative matrix factorization signatures.

RESULTS

The novel cohort of patients with NF1 validated that our previous cfDNA copy-number alteration-based approach identifies malignant PNST (MPNST) but cannot distinguish between benign and premalignant states. Fragmentomic methods were able to differentiate premalignant states including atypical neurofibromas (AN). Fragmentomics also adjudicated AN cases suspicious for MPNST, correctly diagnosing samples noninvasively, which could have informed clinical management.

CONCLUSIONS

Novel cfDNA fragmentomic signatures distinguish AN from benign plexiform neurofibromas and MPNST, enabling more precise clinical diagnosis and management. This study pioneers the early detection of malignant and premalignant PNST in NF1 and provides a blueprint for decentralizing noninvasive cancer surveillance in hereditary cancer predisposition syndromes.

Chemical genetic screens reveal defective lysosomal trafficking as synthetic lethal with NF1 loss

Neurofibromatosis type 1, a genetic disorder caused by pathogenic germline variations in NF1, predisposes individuals to the development of tumors, including cutaneous and plexiform neurofibromas (CNs and PNs), optic gliomas, astrocytomas, juvenile myelomonocytic leukemia, high-grade gliomas and malignant peripheral nerve sheath tumors (MPNSTs), which are chemotherapy- and radiation-resistant sarcomas with poor survival. Loss of NF1 also occurs in sporadic tumors, such as glioblastoma (GBM), melanoma, breast, ovarian and lung cancers. We performed a high-throughput screen for compounds that were synthetic lethal with NF1 loss, which identified several leads, including the small molecule Y102. Treatment of cells with Y102 perturbed autophagy, mitophagy and lysosome positioning in NF1-deficient cells. A dual proteomics approach identified BLOC-one-related complex (BORC), which is required for lysosome positioning and trafficking, as a potential target of Y102. Knockdown of a BORC subunit using siRNA recapitulated the phenotypes observed with Y102 treatment. Our findings demonstrate that BORC might be a promising therapeutic target for NF1-deficient tumors.

Cancer risks related to intellectual disabilities: A systematic review

BACKGROUND

People with intellectual disabilities (ID) face barriers in cancer care contributing to poorer oncological outcomes. Yet, understanding cancer risks in the ID population remains incomplete.

AIM

To provide an overview of cancer incidence and cancer risk assessments in the entire ID population as well as within ID-related disorders.

METHODS

This systematic review examined cancer risk in the entire ID population and ID-related disorders. We systematically searched PubMed (MEDLINE) and EMBASE for literature from January 1, 2000 to July 15, 2022 using a search strategy combining terms related to cancer, incidence, and ID.

RESULTS

We found 55 articles assessing cancer risks in the ID population at large groups or in subgroups with ID-related syndromes, indicating that overall cancer risk in the ID population is lower or comparable with that of the general population, while specific disorders (e.g., Down's syndrome) and certain genetic mutations may elevate the risk for particular cancers.

DISCUSSION

The heterogeneity within the ID population challenges precise cancer risk assessment at the population level. Nonetheless, within certain subgroups, such as individuals with specific ID-related disorders or certain genetic mutations, a more distinct pattern of varying cancer risks compared to the general population becomes apparent.

CONCLUSION

More awareness, and personalized approach in cancer screening within the ID population is necessary.

Neurofibromatosis Type 1: Optimizing Management with a Multidisciplinary Approach

Neurofibromatosis Type I (NF1) is a complex genetic condition that affects multiple organ systems and presents a unique set of challenges for clinicians in its management. NF1 is a tumor predisposition syndrome that primarily affect the peripheral and central nervous systems via the impact of haploinsufficiency upon neural crest lineage cells including Schwann cells, melanocytes, fibroblasts, etc. NF1 can further lead to pathology of the skin, bones, visual system, and cardiovascular system, all of which can drastically reduce a patient's quality of life (QOL). This review provides a comprehensive examination of the many specialties required for the care of patients with Neurofibromatosis Type 1 (NF1). We delve into the pathogenesis and clinical presentation of NF1, highlighting its diverse manifestations and the challenges they pose in management. The review underscores the importance of a multidisciplinary approach to NF1, emphasizing how such an approach can significantly improve patient outcomes and overall QOL. Central to this approach is the role of the NF expert, who guides a multidisciplinary team (MDT) comprising healthcare professionals from many areas of expertise. The MDT collaboratively addresses the multifaceted needs of NF1 patients, ensuring comprehensive and personalized care. This review highlights the need for further investigation to optimize the workflow for NF1 patients in an MDT setting, and to improve implementation and efficacy.

Patient characteristics, treatment patterns, healthcare resource utilization, and costs among patients diagnosed with neurofibromatosis type 1 with and without plexiform neurofibromas in Japan

OBJECTIVES

The objectives of this study were to retrospectively investigate the patient characteristics, treatment patterns, healthcare resource utilization (HCRU), and healthcare costs related to management of neurofibromatosis type 1 (NF1) in Japan.

METHODS

Cohorts of NF1 patients with or without plexiform neurofibromas (PN) were identified from the Medical Data Vision database in 2008-2019. Baseline characteristics, NF1 medications, HCRU, and associated costs were assessed using descriptive statistics. All-cause HCRU and costs following the first confirmed NF1 diagnosis date were analyzed per patient per year (PPPY) in Japanese Yen (JPY) and United States Dollar (USD).

RESULTS

A total of 4394 NF1 patients without PN and 370 NF1 patients with PN were identified. The mean age was 35.0 and 36.9 years, respectively. The proportion of patients with PN treated with medications was higher than that in patients without PN (except for antirheumatic/immunologic agents). Analgesics/non-steroidal anti-inflammatory drugs were the most frequently prescribed NF1 medications (44.3% and 56.0% in patients without and with PN, respectively), followed by inpatient prescriptions of opioids/opioid-like agents (17.8% and 27.6%, respectively). Inpatient admissions accounted for the highest costs in both cohorts with the average cost PPPY being JPY 2,133,277 (USD 19,861) for patients without PN and JPY 1,052,868 (USD 9802) for patients with PN.

CONCLUSIONS

NF1 is treated primarily with supportive care with analgesics/non-steroidal anti-inflammatory drugs being the most frequently prescribed NF1 medications in Japan. Findings underscored the unmet need and substantial economic burden among patients with NF1 and highlighted the need for new treatment options for patients with this disease.

Multidisciplinary team for patients with neurocutaneous syndromes: The little discussed importance of dentistry

Neurocutaneous syndromes comprise a heterogeneous group of congenital or hereditary conditions that are known to be associated with the risk of different disorders and complications. Two of the most common neurocutaneous syndromes are Neurofibromatosis type 1 (NF1) and Tuberous Sclerosis Complex (TSC). Although there appears to be a general consensus on the importance of a multidisciplinary approach in managing these cases, there is still very little emphasis in discussions addressed in the literature on the role of dentistry in accordance with the perspective of comprehensive care. Evidence-based propositions, together with a broad discussion of new insights in this regard, should have the ability to strongly impact related future perspectives, aiming for greater advances and better outcomes for these patients. In this review article, the authors discuss updated general aspects of NF1 and TSC, and the potential additional roles of dentistry, in addition to addressing suggestions for actions in dentistry at related levels of care, as well as priorities for future research.

Conjunctival Marginal Zone Lymphoma in a Patient With Neurofibromatosis Type 1: A Case Report

We present a case of painless bulbar conjunctival mass due to B-cell non-Hodgkin lymphoma (NHL), without systemic involvement, in a 76-year-old man. Following an excision biopsy, histopathologic examination and immunohistochemistry confirmed the diagnosis, prompting a referral for hemato-oncological assessment. The patient underwent comprehensive laboratory and imaging scans, subsequently receiving combined chemo-immunotherapy that resulted in complete remission to date. This case is reported as it is crucial to recognize that a conjunctival insult might emerge in neurofibromatosis type 1 (NF1) patients.

Paranasal Sinus Malignant Peripheral Nerve Sheath Tumour: A Rare Case Report

Malignant Peripheral Nerve Sheath Tumour (MPNST) is a neoplastic lesion rarely reported in literature. In approximately 5% of cases it is associated with Neurofibromatosis type 1 syndrome. Pathognomic features of MPNST include slow growth rate, aggressive nature, nearly circumscribed, unencapsulated arising from non myelinated Schwann cells. In this case report we elaborate probable molecular pathogenesis, clinical features, histopathology (HPE) and radiological findings in a unique case of MPNST. A 52 year old female patient presented with Right cheek swelling, Loss of sensations over right maxillary region, U/L nasal obstruction and watery nasal discharge, palatal buldge and intermittent pain over right maxillary region and generalised headache. Following Magnetic resonance imaging studies (MRI scan) of paranasal sinuses, Biopsy was taken from maxillary mass and palatal swelling. HPE report was suggestive of Spindle cell proliferation against myxoid stroma. Positron Emmision Tomography (PET-Scan) was done and Biopsy specimen was subjected for Immunohistochemistry staining (IHC). After confirmation of MPNST on IHC, patient was referred to skull base surgeon for complete excision of the tumour and reconstruction.

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.

Experience of a single center in the treatment of rare malignant peripheral nerve sheath tumors during the years 1991-2021

Malignant peripheral nerve sheath tumor (MPNST) is a rare sarcoma with a poor prognosis, as the aggressive types of this cancer tend to grow rapidly and metastasize frequently. MPNST is associated with neurofibromatosis type 1 gene mutation. The minority of cases arise secondary to radiation therapy or sporadically. The primary treatment for MPNST is early surgical resection of the tumor. The aim of this study was to retrospectively evaluate the outcome of the treatment of MPNST in Helsinki University Hospital from the years 1991 to 2021. Fourteen MPNST cases were evaluated in this study retrospectively. Descriptive statistical analysis was performed on the collected patient data. Marginal resection was completed in nine cases, wide margins were achieved in three cases, and in two cases the final histological examination of the specimen revealed intralesional removal. During the follow-up time of 36.7 ± 12.1 months, all patients who underwent wide margin resection were alive. One patient died 22 months after intralesional resection and six within 38.3 ± 30.9 months of marginal resection. Seventy-one percent of tumor surgeries resulted in Clavien-Dindo class 3b complications, reflecting the complexity of the surgeries. The aggressive nature of MPNST and the large size of these tumors requires extensive surgery, which can lead to complications. The prognosis of MPNST needs improvement.

Hybrid Techniques of Analyzing MRI Images for Early Diagnosis of Brain Tumours Based on Hybrid Features

Brain tumours are considered one of the deadliest tumours in humans and have a low survival rate due to their heterogeneous nature. Several types of benign and malignant brain tumours need to be diagnosed early to administer appropriate treatment. Magnetic resonance (MR) images provide details of the brain’s internal structure, which allow radiologists and doctors to diagnose brain tumours. However, MR images contain complex details that require highly qualified experts and a long time to analyse. Artificial intelligence techniques solve these challenges. This paper presents four proposed systems, each with more than one technology. These techniques vary between machine, deep and hybrid learning. The first system comprises artificial neural network (ANN) and feedforward neural network (FFNN) algorithms based on the hybrid features between local binary pattern (LBP), grey-level co-occurrence matrix (GLCM) and discrete wavelet transform (DWT) algorithms. The second system comprises pre-trained GoogLeNet and ResNet-50 models for dataset classification. The two models achieved superior results in distinguishing between the types of brain tumours. The third system is a hybrid technique between convolutional neural network and support vector machine. This system also achieved superior results in distinguishing brain tumours. The fourth proposed system is a hybrid of the features of GoogLeNet and ResNet-50 with the LBP, GLCM and DWT algorithms (handcrafted features) to obtain representative features and classify them using the ANN and FFNN. This method achieved superior results in distinguishing between brain tumours and performed better than the other methods. With the hybrid features of GoogLeNet and hand-crafted features, FFNN achieved an accuracy of 99.9%, a precision of 99.84%, a sensitivity of 99.95%, a specificity of 99.85% and an AUC of 99.9%.

Bibliometric analysis of the top 100 most-cited articles in neurofibromatosis

Background:

Neurofibromatosis (NF) is an umbrella term that refers to three distinct disease entities: NF Type 1, Type 2, and schwannomatosis. Here, we reviewed the scientific performance and the most influential publications on NF.

Methods:

A keyword-based search was performed using the Scopus database. The top 100 articles were grouped based on NF types and the studied entities. The differences between the articles, authors, and journals were quantified based on certain parameters. Other parameters were collected for the complete citational analysis.

Results:

The top 100 articles were published between 1961 and 2020. The most trending period of research was in the 1990s and articles studying the clinical aspect and the underlying genetic correlation made up 84% of all articles from the list. The United States of America (USA) had the highest number of contributions (69 articles, 69%). The top institute of contribution to the list was the Howard Hughes Medical Institute, USA (14 articles, 14%). Author-based analysis reveals that the neurologist D. H. Gutmann from St. Louis Children’s Hospital, USA, was the most active and authored 11 articles (11%) on the list.

Conclusion:

The publication trends show that articles studying medical and surgical management were of little interest. The top 100 articles did not include any randomized control trials, and the highest level of evidence was obtained from reviews of pooled knowledge as well as population-based and longitudinal studies.

Epidemiological profile and clinical characteristics of 491 Brazilian patients with neurofibromatosis type 1

BACKGROUND

Neurofibromatosis type 1 (NF1) is a chronic and progressive autosomal dominant genetic and sporadic disease characterized by cutaneous and neurological abnormalities. Plexiform neurofibroma (PN), a significant cause of clinical complications in NF-1, is a benign tumor of the peripheral nerve sheath that involves multiple nerve fascicles. Although there is an important number of patients who are affected by NF1 in Brazil, there is little data on the behavior of the disease in the national literature as well as in other low- and middle-income countries.

METHODS

We performed a retrospective analysis of 491 patients with NF1 followed at two reference centers in Brazil.

RESULTS

Approximately 38% of patients had PNs, resulting in reduced life quality. The median patient age with PNs was 30 years (range: 6 to 83 years). Head and neck, and extremity were the main affected locations with 35.8 and 30.6%, respectively. PNs were classified as asymptomatic in 25.1% of patients, while 52.5% presented symptomatic and inoperable tumors. The most common manifestations related to PNs were disfigurement and orthopedic involvement. Twenty patients developed neoplasms and ten (50%) presented with malignant peripheral nerve sheath tumors (MPNST). The prevalence of MPNST in our study was 2.9%.

CONCLUSIONS

Patients with NF1 experience clinically significant morbidity, especially when it is associated with PN. Though there are many patients affected by NF1 in Brazil and other low- and middle-income countries, there is little data available in the corresponding literature. Our results are comparable to the previous results reported from higher-income countries and international registries.

Tumor and Constitutional Sequencing for Neurofibromatosis Type 1

NF1 variants in tumors are important to recognize, as multiple mechanisms may give rise to biallelic variants. Both deletions and copy-neutral loss of heterozygosity (LOH) are potential mechanisms of NF1 loss, distinct from point mutations, and additional genes altered may drive different tumor types. This study investigates whether tumors from individuals with neurofibromatosis type 1 (NF1) demonstrate additional gene variants and detects NF1 second hits using paired germline and somatic sequencing. In addition, rare tumor types in NF1 may also be characterized by tumor sequencing.

NF1 second hits are primarily copy-neutral LOH and offer opportunity for variant interpretation

Rare Association between Two Genetic Conditions: Turner Syndrome and Neurofibromatosis Type 1

Turner's syndrome (TS) is a sex chromosome disorder due to loss of either all or part of the X chromosome, in some or all the cells of the body. Neurofibromatosis type 1 (NF-1) is a multisystemic genetic disorder that is only rarely observed in association with Turner syndrome. Only six cases of Turner syndrome associated with NF-1 have been reported in the literature. In this study, we report the first case with TS and NF-1 in a Moroccan child. Case Report. A 16-year-old female was born of a nonconsanguineous marriage. In her family history, her mother had multiple café-au-lait spots with Lisch nodules on ophthalmologic examination. She was diagnosed with TS (karyotype: 45, X) due to short stature and characteristic features. The diagnosis of NF-1 was made according to the presence of four diagnostic criteria of the National Institute of Health Consensus Development Conference. Conclusion. Coexistence of NF-1 with TS is rare. We consider that this may be the seventh case report of TS associated with NF-1.

Coexistence of Three Different Mutations in a Male Infant: neurofibromatosis Type 1, Progressive Familial Intrahepatic Cholestasis Type 2 and LPIN3

IntroductionThe coexistence of progressive familial intrahepatic cholestasis type 2, failure to thrive due to an LPIN3 mutation, and stigmata of neonatal neurofibromatosis represents a complex diagnostic challenge. Case report: We present a child with cholestasis requiring hepatic transplantation, explained by the progressive familial intrahepatic cholestasis type 2, failure to thrive could be contributed to by the LPIN3 mutation, and skin findings along with the family history of the patient was due to neurofibromatosis type 1. Conclusion: Our case illustrates the complexities of multiple genetic mutations in a child.

Circular RNA_0061,587 is associated with the tumorigenesis of neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is a kind of common neurogenetic disorder associated with various developmental deficits. Circular RNAs (circRNAs) have been frequently verified to be crucial modulators in human diseases. However, the functions of circRNAs on the occurrence of NF1 remain largely obscure. In our study, RT-qPCR was applied to analyze circ_0061,587 expression and we noticed that circ_0061,587 expression was overtly elevated in human NF1-associated malignant peripheral nerve sheath tumor (MPNST) cell lines. Meanwhile, the results of loss-of-function assays revealed that silencing of circ_0061,587 hampered the proliferation, migration, and invasion but stimulated the apoptosis of human NF1-associated MPNST cells. In addition, mechanism assays were implemented to unveil the possible regulatory mechanism behind circ_0061,587. As a result, circ_0061,587 sequestered microRNA-485-5p (miR-485-5p) to modulate the expression of RUNX family transcription factor 1 (RUNX1) and annexin A11 (ANXA11). Finally, rescue experiments confirmed that circ_0061,587 boosted the malignant behaviors of human NF1-associated MPNST cells through up-regulating RUNX1 and ANXA11. In conclusion, circ_0061,587 functioned as an oncogene in NF1-associated MPNST cells and this study might provide novel insights for the diagnosis and treatment of NF1.

Current concepts of neurofibromatosis type 1: pathophysiology and treatment

Neurofibromatosis type 1 is the most common tumor predisposition syndrome inherited in an autosomal dominant (100% penetrance) fashion with a wide variety of expressivity. From the perspective of plastic surgery, the most significant clinical symptoms, including disfiguration, peripheral neurologic symptoms, and skeletal abnormalities, are caused by various tumors originating from the affected nerves. Surgical removal is the standard of care for these tumors. However, the outcome is frequently unsatisfactory, facilitating the search for additional therapeutic adjuvants. Current trials of molecularly targeted therapies are promising. Abbreviations: CALMs, café-au-lait macules; CNs, cutaneous neurofibromas; FDG, 18F-fluoro-deoxy-glucose; MAPK, mitogen-activated protein kinase; MPNSTs, malignant peripheral nerve sheath tumors; MRI, magnetic resonance imaging; NF1, neurofibromatosis type 1; NIH, National Institutes of Health; PET, positron emission tomography; PN, plexiform neurofibromas; TME, tumor microenvironment.

Neurofibromatosis in Children: Actually and Perspectives

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.

A case report of malignant peripheral nerve sheath tumour of the left thigh and popliteal fossa with lungs, spleen, and brain dissemination related to neurofibromatosis type 1

A malignant peripheral nerve sheath tumour (MPNST) is a highly aggressive sarcoma. This disease develops in a number of people with neurofibromatosis type 1 (NF1), which is a common genetic disease. The paper presents a patient with typical manifestations of a malignant tumour of the peripheral nerve sheath, in the form of a large tumour of primary localisation in the distal part of the left thigh and left popliteal fossa and with significant dissemination into the lung parenchyma, which was accompanied by respiratory risk. The first operation of the tumour was done four years earlier, after which the patient did not come for regular check-ups. Nine cycles of chemotherapy were performed by Doxorubicin / Ifosfamide / Mesna protocol with clinical improvement and stabilisation, but without a significant impact on the dynamics of the disease and the overall survival was 14 months. It is of utmost importance to early recognise clinical presentation of the malignant form of this tumour and active supervision of a patient with a benign form by experts. In this way, it is possible to apply the optimal treatment modality in a timely manner.

Plexiform neurofibroma: shedding light on the investigational agents in clinical trials

INTRODUCTION

Neurofibromatosis Type 1 (NF1) is an autosomal dominant genetic condition, which predisposes individuals to the development of plexiform neurofibromas (PN), benign nerve sheath tumors seen in 30-50% of patients with NF1. These tumors may cause significant pain and disfigurement or may compromise organ function. Given the morbidity associated with these tumors, therapeutic options for patients with NF1-related PN are necessary.

AREAS COVERED

We searched the www.clinicaltrials.gov database for 'plexiform neurofibroma.' This article summarizes completed and ongoing trials involving systemic therapies for PN.

EXPERT OPINION

Surgery is the mainstay treatment; however, complete resection is not possible in many cases. Numerous systemic therapies have been evaluated in patients with NF1, with MEK inhibitors (MEKi) showing the greatest efficacy for volumetric reduction and improvement in functional and patient-reported outcomes. The MEKi selumetinib is now FDA approved for the treatment of inoperable, symptomatic PN in pediatric NF1 patients. Questions remain regarding the use of this drug class in terms of when to initiate therapy, overall duration, reduced dosing schedules, and side effect management. Future studies are needed to fully understand the clinical application of MEKi and to evaluate other potential therapies through appropriate trial designs for this potentially devastating, manifestation in NF1.

Diffusion-Weighted Magnetic Resonance Imaging Improves the Accuracy of Differentiation of Benign from Malignant Peripheral Nerve Sheath Tumors

OBJECTIVE

In patients with neurofibromatosis type 1 (NF1), it is important to accurately determine when plexiform neurofibroma (pNF) transforms to a malignant peripheral nerve sheath tumor (MPNST). The purpose of this study is to investigate the usefulness of diffusion-weighted imaging (DWI) in differentiating pNF and MPNST in NF1 patients.

METHODS

Among the NF1 patients who were referred to our hospital between 1985 and 2015, 10 cases of MPNST and 19 cases of pNF were included. We evaluated features of standard magnetic resonance imaging according to the differentiation criteria of malignancy from benignancy as previously reported, apparent diffusion coefficient (ADC) value based on the DWI and the correlation between ADC value and benignancy/malignancy. ROC analysis was performed to determine the appropriate cutoff value of ADC.

RESULTS

There were significant differences between MPNST and pNF in the size of the tumor (P = 0.009), peripheral enhancement pattern (P = 0.002), perilesional edema-like zone (P = 0.0008), and intratumoral cystic change (P = 0.02). The mean and minimum values of ADC were significantly lower in MPNST than those in pNF (P = 0.03 and P = 0.003, respectively). When we set a cutoff value of mean ADC as 1.85 × 10^-3 mm²/s, the sensitivity and specificity were 80% and 74%, respectively. The area under the curve value improved by adding the Wasa score to the mean ADC evaluation.

CONCLUSIONS

ADC values determined by DWI are useful in differentiating MPNST from pNF and adding ADC evaluation to standard MRI evaluation improved the diagnostic accuracy.

A case of appendiceal ganglioneuroma in neurofibromatosis type 1

BACKGROUND

Neurofibromatosis type 1 is an autosomal dominant inherited disease associated with multiple skin neurofibromas or other neurogenic tumors, such as nodular plexiform neurinoma or cerebrospinal tumor. Gastrointestinal stromal tumors are often complicated in patients with neurofibromatosis type 1, although involvement of the appendix is rare, and there have been few reports of appendiceal ganglioneuroma.

CASE PRESENTATION

The patient was a 29-year-old man diagnosed with neurofibromatosis type 1 based on physical findings and his family history. During the follow-up of neurofibromatosis, computed tomography was performed to detect neurological tumors, such as neurofibromas in the brain, spinal cord, and gastrointestinal tract. Computed tomography showed a markedly thickened appendix wall, and an appendiceal tumor was suspected. Laparoscopic appendectomy was performed, and a 50 × 35 mm appendiceal submucosal tumor was resected with a negative resection margin. At histopathological examination, the tumor was diagnosed as ganglioneuroma; it showed short spindle-shaped cells and ganglion cells diffusely infiltrated into the proper muscle layer and fibrous tissue that grew around nerve cells. The patient was discharged on the 5th postoperative day without postoperative complications and was doing well at 13 months following the operation.

CONCLUSIONS

Gastrointestinal stromal tumor and neurofibroma are the most common gastrointestinal tumors associated with neurofibromatosis type 1, but ganglioneuroma of the appendix is rare. Appendiceal neurogenic tumors should be considered in patients with neurofibromatosis type 1, and surgical resection is necessary because of the risk of malignancy.

Characteristics, treatment patterns, healthcare resource use, and costs among pediatric patients diagnosed with neurofibromatosis type 1 and plexiform neurofibromas: a retrospective database analysis of a medicaid population

OBJECTIVES

The objectives of this study were to describe the characteristics and initial treatment patterns, healthcare resource use (HCRU), and costs of patients newly diagnosed with neurofibromatosis type 1 (NF1)-related plexiform neurofibromas (PN).

METHODS

This was a retrospective study of individuals enrolled in the IBM MarketScan Multi-State Medicaid database from 1 October 2014 to 31 December 2017. Patients aged ≤18 years at the index date (first diagnosis of NF1 or PN, whichever occurred later) with at least 1 ICD-10-CM diagnosis code for both NF1 and PN were included. All-cause HCRU and the associated direct costs during the follow-up period were calculated per patient per year (PPPY) in 2018 USD.

RESULTS

A total of 383 patients were included with a mean follow-up of 448 days. Most patients were diagnosed by a specialist (63.5%). During the follow-up period, pain medications were used by 58.5% of patients, 25.1% were treated with chemotherapy, 7.1% received surgery for PN, 1.6% received MEK inhibitors, and 0.8% received radiation. Mean PPPY inpatient, outpatient, ER, pharmacy, and other visits were 1.4, 17.3, 1.6, 13.6, and 25.8, respectively. Mean ± SD (median) total PPPY healthcare costs were $17,275 ± $61,903 ($2889), with total medical costs of $14,628 ± $56,203 ($2334) and pharmacy costs of $2646 ± $13,303 ($26).

CONCLUSIONS

This study showed that many pediatric patients newly diagnosed with NF1 and PN were initially treated with supportive care only, highlighting a substantial unmet medical need. This study also highlights the considerable economic burden among patients with NF1 and PN.

Effects of Age on White Matter Microstructure in Children With Neurofibromatosis Type 1

Children with neurofibromatosis type 1 (NF1) often report cognitive challenges, though the etiology of such remains an area of active investigation. With the advent of treatments that may affect white matter microstructure, understanding the effects of age on white matter aberrancies in NF1 becomes crucial in determining the timing of such therapeutic interventions. A cross-sectional study was performed with diffusion tensor imaging from 18 NF1 children and 26 age-matched controls. Fractional anisotropy was determined by region of interest analyses for both groups over the corpus callosum, cingulate, and bilateral frontal and temporal white matter regions. Two-way analyses of variance were done with both ages combined and age-stratified into early childhood, middle childhood, and adolescence. Significant differences in fractional anisotropy between NF1 and controls were seen in the corpus callosum and frontal white matter regions when ages were combined. When stratified by age, we found that this difference was largely driven by the early childhood (1-5.9 years) and middle childhood (6-11.9 years) age groups, whereas no significant differences were appreciable in the adolescence age group (12-18 years). This study demonstrates age-related effects on white matter microstructure disorganization in NF1, suggesting that the appropriate timing of therapeutic intervention may be in early childhood.

Neurofibromatosis and HIV infection in a pregnant woman

Although pregnant neurofibromatosis or HIV patient established a high-risk group, this report demonstrated that a careful planning and widespread valuations should be associated with a favorable prognosis for both mother and newborn.

A Rare Perineurioma/Granular Cell Tumor Hybrid Peripheral Nerve Sheath Tumor

Hybrid peripheral nerve sheath tumors (PNSTs) are rare benign composite neoplasms demonstrating features of multiple endogenous nerve sheath cell types. Hybrid PNSTs with granular cell components are exceedingly rare. Only a handful number of hybrid PNSTs composed of granular cell tumor and perineurioma have been described to date. We present a rare hybrid of perineurioma and granular cell tumor and review the literature.

Epidemiological and clinical burden associated with plexiform neurofibromas in pediatric neurofibromatosis type-1 (NF-1): a systematic literature review

PURPOSE

Patients with neurofibromatosis type-1 (NF-1) and associated plexiform neurofibromas (PNs) often have a high burden of illness owing to debilitating symptoms of these tumors and limited management options. To investigate this complex disease, a systematic literature review (SLR) was conducted on the epidemiology of pediatric NF-1 and associated PNs, the burden of illness, and outcomes of surgical resection of these tumors.

METHODS

Searches of MEDLINE and Embase (from database inception to October 2019) and conference proceedings (2017-2019) were performed to identify relevant studies. The review methodology was informed by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

Twenty studies were identified. Evidence confirmed NF-1 is rare but that occurrence may differ geographically. Only limited data on the birth incidence of NF-1 were identified. Prevalence estimates for pediatric NF-1 varied from one per 960 individuals (aged 17 years) to one per 5681 children (aged < 16 years) across five large registry/surveillance studies (each involving > 19,000 individuals). The prevalence of associated PNs was 0-29.6%. PNs carried increased mortality risk in pediatric NF-1 in both studies that explored this potential association. Patients with PNs reported high use of analgesics. The complication rate post-surgery for PNs was around 17-19%. The recurrence rate (18-68%) was dependent on the extent of excision achieved during surgery.

CONCLUSIONS

Data suggest NF-1 is a rare disease with increased morbidity and mortality in children with associated PNs. Surgical outcomes for PNs are often poor. These findings suggest significant unmet needs in patients with NF-1-associated PNs.

Coincidental Expression of Classic Hodgkin Lymphoma and Neurofibromatosis Type I and Literature Review

Neurofibromatosis Type 1 (NF1) is a genetic disorder with an incidence of 1 in 2600 to 3000 individuals. It is a clinical diagnosis characterized by café-au-lait macules, neurofibromas, and axillary and/or groin freckling. Because of genetic mutations in the NF1 gene affecting the Ras/mitogen-activated protein kinase pathway, there is also risk of associated soft tissue sarcomas and hematologic malignancies. However, reports of classic Hodgkin lymphoma in patients with NF1 are sparse. We report an adolescent with NF1 who developed classic Hodgkin lymphoma. Although there is an unclear association between mutations in the NF1 gene and classic Hodgkin lymphoma, further studies are warranted.

An Unusual Association between Neurofibromatosis Type 1 and Diffuse B Cell Lymphoma

Neurofibromatosis type 1 (NF-1) is known to be associated with increased risk of malignancy by at least fourfold. Malignant lymphomas are rare in adults with NF-1. Hereby, we present a 75-year-old male with NF-1 complaining of weakness, nausea, and vomiting associated with abdominal pain. Three months prior to presentation, he had suffered a motor vehicle accident (MVA) resulting in multiple rib fractures that was seen in chest X-ray. For the following three months, he had intermittent chest pain, but it was attributed to the recent rib fracture. During this admission, the severity of chest pain worsened and the associated vomiting inclined further investigation; including CT imaging and bone biopsy, it was revealed to be a rare case of diffuse B cell lymphoma in a patient with NF-1. However, we believe the recent MVA caused an anchoring bias in making a prompt diagnosis. In addition, the appearance of the neurofibroma, resulted in suboptimal physical examination, and hence, there was a delay in reaching the diagnosis. We will discuss here the presentation of this case, to highlight the rare association and to increase awareness of when encountering a challenging diagnosis.

Case Report: Chemotherapy Indication in a Case of Neurofibromatosis Type 1 Presenting Optic Pathway Glioma: A One-Year Clinical Case Study Using Differential Tractography Approach

Neurofibromatosis type 1 (NF1) is associated with peripheral and central nervous system tumors. It is noteworthy that the regions in which these tumors frequently arise are the optic pathways (OPs) and the brainstem. Thus, we decided to trace the procedure of diffusion Magnetic Resonance Imaging (dMRI) alterations along with Short-Wavelength Automated Perimetry (SWAP) examinations of the OPs after surgery and chemotherapy over 1 year, which enabled us to evaluate chemotherapy's efficacy in an NF1 patient with an OP tumor. In this study, a 25-year-old woman with NF1 and left optic radiation (OR) glioma underwent surgery to remove the glioma. Immunohistochemistry (IHC) revealed a Pilocytic Astrocytoma (PA) WHO grade I. Post-operation chemotherapy done using nine treatment cycles of administering Temozolomide (TMZ) for 5 days every 4 weeks. Applying the region of interest (ROI) differential tractography method and SWAP four times every 3 months allowed us to follow the patient's visual acuity alterations longitudinally. The differential deterministic tractography method and statistical analyses enabled us to discover the white matter (WM) tracts anisotropy alterations over time. Furthermore, statistical analyses on the SWAP results along time illustrated possible alterations in visual acuity. Then, we could compare and associate the findings with the SWAP examinations and patient symptoms longitudinally. Statistical analyses of SWAP tests revealed a significant improvement in visual fields, and longitudinal differential tractography showed myelination and dense axonal packing in the left OR after 1 year of treatment. In this study, we examined an old hypothesis suggesting that chemotherapy is more effective than radiotherapy for NF1 patients with OP gliomas (OPGs) because of the radiation side effects on the visual field, cognition, and cerebrovascular complications. Our longitudinal clinical case study involving dMRI and SWAP on a single NF1-OPG patient showed that chemotherapy did not suppress the OP myelination over time. However, it should be noted that this is a clinical case study, and, therefore, the generalization of results is limited. Future investigations might focus on genetic-based imaging, particularly in more cases. Further, meta-analyses are recommended for giving a proper Field Of View (FOV) to researchers as a subtle clue regarding precision medicine.

Comparison of Cancer Prevalence in Patients With Neurofibromatosis Type 1 at an Academic Cancer Center vs in the General Population From 1985 to 2020

IMPORTANCE

Neurofibromatosis type 1 (NF1) is a complex genetic disorder that is associated with not only neurofibromas, but also an increased susceptibility to other neoplasms.

OBJECTIVE

To evaluate the prevalence of neoplasia and outcomes among patients with NF1.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study was conducted among patients with NF1 at a single academic cancer center from 1985 to 2020 with median (range) follow-up of 2.9 years (36 days to 30.5 years). Of 2427 patients evaluated for NF1, 1607 patients who met the National Institutes of Health consensus criteria for NF1 were included. This group was compared with estimates from Surveillance, Epidemiology, and End Results (SEER) Cancer Statistics Review 1975 to 2015 and SEER participants database unless otherwise specified. Data were analyzed from August 2018 to March 2020.

MAIN OUTCOMES AND MEASURES

Disease-specific survival (DSS) was measured from diagnosis date to date of neoplasm-specific death or censorship and calculated using the Kaplan-Meier method. Survival curves were compared using the log-rank test. Deaths from disease were considered a DSS end point; other deaths were considered censored observations. Secondary outcome measures were comparisons of (1) overall survival of patients with NF1 with neurofibroma neoplasms vs those without nonneurofibroma neoplasms, (2) neoplasm prevalence in the NF1 group vs general population estimates, and (3) age at diagnosis in the NF1 group vs general population estimates for the most common neoplasms in the NF1 group.

RESULTS

Among 1607 patients with NF1, the median (range) age at initial visit was 19 years (1 month to 83 years) and 840 (52.3%) were female patients. Among 666 patients who developed other neoplasms in addition to neurofibromas (41.4%), 295 patients (18.4%) developed glioma and 243 patients (15.1%) developed malignant peripheral nerve sheath tumor (MPNST), the most common neoplasms. Patients with NF1, compared with the general population, developed several neoplasms at a younger mean (SD) age (low-grade glioma: 12.98 [11.09] years vs 37.76 [24.53] years; P < .0001; high-grade glioma [HGG]: 27.31 [15.59] years vs 58.42 [19.09] years; P < .0001; MPNST: 33.88 [14.80] years vs 47.06 [20.76] years; P < .0001; breast cancer: 46.61 [9.94] years vs 61.71 [13.85] years; P < .0001). Patients with NF1 developed neoplasms more frequently compared with the general population (odds ratio, 9.5; 95% CI, 8.5-10.5; P < .0001). Among patients with NF1, significantly lower 5-year DSS rates were found among those with undifferentiated pleomorphic sarcoma (1 of 5 patients [20.0%]), HGG (8 of 34 patients [23.1%]), MPNST (72 of 228 patients [31.6%]), ovarian carcinoma (4 of 7 patients [57.1%]), and melanoma (8 of 12 patients [66.7%]) compared with those who had neoplasms classified as other (110 of 119 patients [92.4%]) (all P < .001) .

CONCLUSIONS AND RELEVANCE

This cohort study found that among patients with NF1, those who developed undifferentiated pleomorphic sarcoma, HGG, MPNST, ovarian carcinoma, or melanoma had significantly lower DSS rates compared with those who developed other neoplasms. This study also found that patients with NF1 developed some neoplasms more frequently and at a younger age compared with individuals without NF1. HGGs and MPNST were noteworthy causes of death among patients NF1. This information may be useful for NF1 patient counseling and follow-up.

Clinical outcomes of non-osteogenic, non-Ewing soft-tissue sarcoma of bone--experience of the Toronto Sarcoma Program

Non‐osteogenic, non‐Ewing soft‐tissue sarcoma (NONE‐STS) of bone is a rare presentation of primary bone cancers. Optimal treatments and outcomes for this heterogenous group are poorly described. We evaluated the factors associated with long‐term outcomes in patients with this disease. Patients with localized NONE‐STS of bone treated at the Toronto Sarcoma Program from 1987 to 2017 were identified. Clinical characteristics, treatment, and survival information were collected. Kaplan‐Meier (log‐rank) survival estimates from the time of definitive surgery, with uni‐/multivariate analyses (Cox) of sarcoma‐specific survival were performed. A total of 106 patients (60.4% male; median age 46 years) with NONE‐STS of bone were identified. Common histologies included undifferentiated pleomorphic sarcoma [UPS]/malignant fibrous histiocytoma [MFH] (UPS/MFH, 41.5%), leiomyosarcoma (LMS, 20.8%), and fibrosarcoma (FS, 11.3%). Tumors were often high grade (59.4%) and involved the extremities (88.7%), with most receiving chemotherapy (67.9%) with cisplatin/doxorubicin‐based regimens (73.6%). In the full cohort, 10‐year DFS (45.7%, [95%CI: 35.7‐55.8%]), OS (53.4%, [95%CI: 41.7‐62.2%]), and SSS (63.9%, [95%CI: 53.9‐72.5%]) were moderate. Histology specific, 10‐year SSS was 70.7% [95%CI: 56.1‐85.5%] for UPS/MFH, 51.8% [95%CI: 29.8‐73.8%] for LMS, and 72.2% [95%CI: 45.1‐99.2%] for FS. Only UPS/MFH (n = 4) showed sarcoma‐related death >10 years. Multivariate analysis identified axial location (HR = 35.5, [95%CI: 3.4‐369.6]), high grade (HR = 16.9, [95%CI: 1.6‐185.1]), and disease relapse (HR = 485.1, [95%CI: 36.3‐6482.6]) as risk factors for death (p < 0.05). Treatment with chemotherapy (HR = 0.1, [95%CI: 0.01‐0.86]) and necrosis ≥85% (HR = 0.2, [95%CI: 0.04‐0.99]) showed improved survival (p < 0.05). NONE‐STS of bone has favorable long‐term survival similar to osteosarcoma. Patients receiving chemotherapy derive benefit in retrospective analyses. UPS/MFH histologies show sarcoma‐related death beyond 10 years. Further data on histologic subgroups are needed.

Treatment, Resource Use and Costs Among Pediatric Patients with Neurofibromatosis Type 1 and Plexiform Neurofibromas

Background

Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic condition which predisposes individuals to tumors of the nervous system, skin, bones, and eyes. Plexiform neurofibromas (PNs) occur in 20-50% of NF1 cases, causing multiple morbidities and conferring a risk of malignancy. NF1 with PN is poorly characterized in the literature with regard to treatment patterns, healthcare resource utilization, and costs in the real world.

Methods

This was a retrospective analysis of data from a commercial claims database in the US between October 2014 and March 2018. Persons with at least 1 diagnostic code for both NF1 and PN, aged ≤18 years on the index date, and continuously enrolled for ≥12 months before the index date were included. The index date was defined as the date of the first diagnosis of NF1 or PN during the study period, whichever occurred later. Healthcare resource utilization during follow-up included outpatient, inpatient, emergency room (ER), and pharmacy encounters; corresponding costs were calculated as the mean per patient per year (PPPY) in 2018 US dollars. Treatments were classified as PN surgery, pain medication, chemotherapy, radiotherapy, and targeted therapies. All analyses were descriptive.

Results

A total of 301 patients were included. In the follow-up period, nearly all patients (99.7%) had outpatient visits, while 81.1% had pharmacy visits, 25.2% had ER visits, and 13.0% had inpatient visits. Mean ± SD [median] total healthcare costs PPPY were $38,292 ± $80,556 [$16,037]. During follow-up, 44.2% of patients used pain medications, 23.9% received chemotherapy, 5.0% underwent surgery for PN, 1.3% received radiotherapy, and 1.0% received targeted therapies.

Conclusion

Commercially insured pediatric patients diagnosed with NF1 and PN were treated primarily with supportive care, highlighting a substantial unmet need in the United States.

Clinical characterization of children and adolescents with NF1 microdeletions

PURPOSE

An estimated 5-11% of patients with neurofibromatosis type 1 (NF1) harbour NF1 microdeletions encompassing the NF1 gene and its flanking regions. The purpose of this study was to evaluate the clinical phenotype in children and adolescents with NF1 microdeletions.

METHODS

We retrospectively analysed 30 children and adolescents with NF1 microdeletions pertaining to externally visible neurofibromas. The internal tumour load was determined by volumetry of whole-body magnetic resonance imaging (MRI) in 20 children and adolescents with NF1 microdeletions. Furthermore, the prevalence of global developmental delay, autism spectrum disorder and attention deficit hyperactivity disorder (ADHD) were evaluated.

RESULTS

Children and adolescents with NF1 microdeletions had significantly more often cutaneous, subcutaneous and externally visible plexiform neurofibromas than age-matched patients with intragenic NF1 mutations. Internal neurofibromas were detected in all 20 children and adolescents with NF1 microdeletions analysed by whole-body MRI. By contrast, only 17 (61%) of 28 age-matched NF1 patients without microdeletions had internal tumours. The total internal tumour load was significantly higher in NF1 microdeletion patients than in NF1 patients without microdeletions. Global developmental delay was observed in 28 (93%) of 30 children with NF1 microdeletions investigated. The mean full-scale intelligence quotient in our patient group was 77.7 which is significantly lower than that of patients with intragenic NF1 mutations. ADHD was diagnosed in 15 (88%) of 17 children and adolescents with NF1 microdeletion. Furthermore, 17 (71%) of the 24 patients investigated had T-scores ≥ 60 up to 75, indicative of mild to moderate autistic symptoms, which are consequently significantly more frequent in patients with NF1 microdeletions than in the general NF1 population. Also, the mean total T-score was significantly higher in patients with NF1 microdeletions than in the general NF1 population.

CONCLUSION

Our findings indicate that already at a very young age, NF1 microdeletions patients frequently exhibit a severe disease manifestation which requires specialized long-term clinical care.

Structural Insights into the SPRED1-Neurofibromin-KRAS Complex and Disruption of SPRED1-Neurofibromin Interaction by Oncogenic EGFR

Sprouty-related, EVH1 domain-containing (SPRED) proteins negatively regulate RAS/mitogen-activated protein kinase (MAPK) signaling following growth factor stimulation. This inhibition of RAS is thought to occur primarily through SPRED1 binding and recruitment of neurofibromin, a RasGAP, to the plasma membrane. Here, we report the structure of neurofibromin (GTPase-activating protein [GAP]-related domain) complexed with SPRED1 (EVH1 domain) and KRAS. The structure provides insight into how the membrane targeting of neurofibromin by SPRED1 allows simultaneous interaction with activated KRAS. SPRED1 and NF1 loss-of-function mutations occur across multiple cancer types and developmental diseases. Analysis of the neurofibromin-SPRED1 interface provides a rationale for mutations observed in Legius syndrome and suggests why SPRED1 can bind to neurofibromin but no other RasGAPs. We show that oncogenic EGFR(L858R) signaling leads to the phosphorylation of SPRED1 on serine 105, disrupting the SPRED1-neurofibromin complex. The structural, biochemical, and biological results provide new mechanistic insights about how SPRED1 interacts with neurofibromin and regulates active KRAS levels in normal and pathologic conditions.

Incidence of second malignancies in individuals diagnosed with malignant peripheral nerve sheath tumors

BACKGROUND

The incidence of malignant peripheral nerve sheath tumors (MPNSTs) is low in the general population, although individuals with Neurofibromatosis Type I (NF1) are particularly susceptible. These tumors generally have a high probability of metastasis. The rate and types of second malignancies (SMNs) after a primary diagnosis of MPNST are not well characterized. We aimed to quantify the rate of SMNs among individuals with a first primary MPNST using population-based data.

METHODS

We estimated age-standardized incidence rates (SIRs) for SMNs among 1,579 primary MPNST cases between ages 0-85+ using SEER 18 (2000-2015). We estimated incidence rate ratios (IRRs) and 95% confidence intervals (95% CI) for SMNs in MPNST cases compared with general population rates. We conducted sex-stratified and age-restricted analyses (< 30 years at diagnosis).

RESULTS

Seven percent (108/1579) of MPNST cases developed a SMN (SIR of 4635 cases/million). Compared to the general population, MPNST cases were more likely to develop SMNs (IRR: 29.3; 95% CI 23.8-34.8) and had a much higher rate of second MPNSTs (IRR: 15,992.9; 95% CI 9594.5-22,391.3). Aside from a second MPNST, second cancers were frequently diagnosed in the breast, lung, skin, and soft tissue in females and were myeloid and skin malignancies in males. When restricted to < 30 years of age, second MPNSTs were the most common cancers diagnosed.

CONCLUSIONS

The rate of SMNs among MPNST cases is tremendously higher than that observed among individuals with other cancers, particularly for second MPNSTs. These findings suggest rates of SMNs may also be higher in NF1 individuals.

Challenges in staging and surveillance of patients with neurofibromatosis and cutaneous malignant melanoma

Malignant melanoma is a skin neoplasm with a rising trend of incidence. Positron Emission Tomography in combination with Computed Tomography (PET-CT) imaging is an essential diagnostic tool for both staging and surveillance of melanoma patients; especially in metastatic disease, where prognosis is poor. We report a case of a patient with known Neurofibromatosis type 1 (NF-1) who presented to the Skin Cancer Multidisciplinary meeting with 11 mm Breslow thickness malignant melanoma of the left forearm. His extensive dermal neurofibromatoses proved a diagnostic challenge to the team. There have been published studies linking NF-1 with malignant melanoma. However the incidence and significance of this has yet to be established. We also discuss the use of PET-CT imaging and skin surveillance in the monitoring and staging of this patient.

An Update on Neurofibromatosis Type 1-Associated Gliomas

Neurofibromatosis type 1 (NF1) is an autosomal dominant tumor predisposition syndrome that affects children and adults. Individuals with NF1 are at high risk for central nervous system neoplasms including gliomas. The purpose of this review is to discuss the spectrum of intracranial gliomas arising in individuals with NF1 with a focus on recent preclinical and clinical data. In this review, possible mechanisms of gliomagenesis are discussed, including the contribution of different signaling pathways and tumor microenvironment. Furthermore, we discuss the recent notable advances in the developing therapeutic landscape for NF1-associated gliomas including clinical trials and collaborative efforts.

Cerebellar glioblastoma multiforme in an adult patient with neurofibromatosis type 1: an extremely rare report with review of literature

Background

Neurofibromatosis type 1 (NF1) is a multisystem genetic disorder with autosomal dominant inheritance which predisposes the affected individuals to increased risk of developing certain benign and malignant central nervous system (CNS) tumors. NF1 patients are most notably prone to develop low-grade optic pathway, brainstem, and cerebellar astrocytoma. Current literature suggests that brain tumors in patients with NF1 tend to be less aggressive compared to sporadic ones. Glioblastoma multiforme (GBM) is a high-grade glioma which is relatively rare in patients with NF1 and is most commonly seen in supratentorial regions of the brain.

Case presentation

A 33-year-old patient was admitted in neurosurgery ward with acute hydrocephalus caused by a cerebellar mass lesion. On primary assessment, the patient was diagnosed with NF1. He was followed for 2 months and underwent surgical resection of the mass due to worsening symptoms. The pathology report revealed the malignant nature of the lesion. Patient received adjuvant chemo-radiotherapy with diagnosis of cerebellar GBM. Up to 19 months following surgery, he had gained a relatively well ability to walk and talk again.

Pediatric peripheral nerve tumors: clinical and surgical aspects

PURPOSE

Pediatric peripheral nerve tumors (PNTs) are rare. Most are related to neurofibromatosis type 1 (NF1) with the potential for malignancy. An ongoing debate occurs about the best approach to such patients. This study describes a cohort of pediatric patients with PNTs and discusses clinical characteristics and surgical treatment.

METHODS

We retrospectively reviewed the charts of seven pediatric patients with eight PNTs surgically treated from 2007 to 2018. Information concerning patient demographics, clinical presentation, PNTs characteristics, treatment choice, and outcome were recorded.

RESULTS

All children presented with intense pain and a palpable mass. Three of the eight tumors were associated with a neurological deficit. Among the four patients with NF1, two had a neurofibroma and two a malignant peripheral nerve sheath tumor (MPNST). Histologically, three of the lesions were a benign peripheral nerve sheath tumor (BPNST), three a MPNST, and one each a desmoid tumor and Ewing's sarcoma. Two of the eight tumors underwent partial tumor excision and six gross total excisions.

CONCLUSIONS

Intense pain at rest, day, and/or night, preventing normal activities; a palpable, hard, immobile mass; an intense Tinel's sign related to the lump; clinical evidence of NF1; and high-speed growth of a tumor in the trajectory of the nerve or plexus should alert the clinician to the potential for malignancy. Preoperative biopsy is not indicated when clinical and imaging findings suggest a benign tumor. The surgical management of PNTs must be to achieve total resection, including wide margins with malignant tumors, though this is not always possible.

KRAS G13D sensitivity to neurofibromin-mediated GTP hydrolysis

KRAS mutations occur in ∼35% of colorectal cancers and promote tumor growth by constitutively activating the mitogen-activated protein kinase (MAPK) pathway. KRAS mutations at codons 12, 13, or 61 are thought to prevent GAP protein-stimulated GTP hydrolysis and render KRAS-mutated colorectal cancers unresponsive to epidermal growth factor receptor (EGFR) inhibitors. We report here that KRAS G13-mutated cancer cells are frequently comutated with NF1 GAP but NF1 is rarely mutated in cancers with KRAS codon 12 or 61 mutations. Neurofibromin protein (encoded by the NF1 gene) hydrolyzes GTP directly in complex with KRAS G13D, and KRAS G13D-mutated cells can respond to EGFR inhibitors in a neurofibromin-dependent manner. Structures of the wild type and G13D mutant of KRAS in complex with neurofibromin (RasGAP domain) provide the structural basis for neurofibromin-mediated GTP hydrolysis. These results reveal that KRAS G13D is responsive to neurofibromin-stimulated hydrolysis and suggest that a subset of KRAS G13-mutated colorectal cancers that are neurofibromin-competent may respond to EGFR therapies.

CHD4 as a Potential Biomarker in Differentiating Between Cellular Schwannoma and Malignant Peripheral Nerve Sheath Tumor

Cellular schwannoma is an uncommon variant of benign peripheral nerve sheath tumors, but is commonly misdiagnosed as malignant peripheral sheath tumor (MPNST). Conventional methods that are used to distinguish cellular schwannoma from MPNST include immunohistochemistry (IHC) staining. However, most markers cannot precisely differentiate these 2 tumor types, and thus identification of a better marker is needed to improve the accuracy of diagnosis. Here, we evaluate the use of chromodomain helicase DNA-binding protein 4 (CHD4) as a specific marker for cellular schwannoma by comparing CHD4 and S-100 IHC staining in 14 cellular schwannoma and 17 MPNST tissue samples. Our results indicated that nuclear CHD4 stains were in moderate-to-high in 94% MPNST (16 cases) and 93% cellular schwannoma (13 cases). However, cytoplasmic CHD4 stains were moderate-to-high in 93% cellular schwannoma (13 cases) but negative-to-weak in 100% MPNST (17 cases). In contrast, the S-100 stains were moderate-to-high in 86% of the cellular schwannoma (12 cases) and in 35% of the MPNST (6 cases). Taken together, the results indicated that different location of CHD4 staining is a potential biomarker to differentiate cellular schwannoma from MPNST.