Neurofibromatosis Research Articles

Moyamoya syndrome associated with plexiform neurofibromatosis type 1 presenting with hemichorea

Moyamoya syndrome associated with plexiform neurofibromatosis type 1 presenting with hemichorea

Neurofibromatosis type 1: short review and clinical case

Neurofibromatosis type 1 (NF1) is acommon (1/3000) autosomal dominant disorder associated with amutation in the NF1 gene, located on the long arm of chromosome 17 (17q11.2). NF1 is diagnosed using well-known clinical criteria: café au lait spots, axillary and inguinal freckles, cutaneous and subcutaneous neurofibromas, optic pathway gliomas, and specific bone abnormalities. The pathognomonic feature of the disease is plexiform neurofibroma (PN), which is abenign peripheral nerve sheath tumor that occurs in 30-50% of patients with NF1. In addition to awide range of clinical manifestations, such as pain, motor, respiratory disorders, neurological deficits, cosmetic defects, etc., there is about a15% risk for the development of malignant peripheral nerve sheath tumors (MPNST). And it should be noted that the treatment of PN is acomplex task that does not have one standard solution. Thus, surgical treatment, which was the “gold standard” and remains one of the main methods of therapy, carries significant risks, such as postoperative neurological deficit, ahigh risk of intraoperative bleeding and is accompanied by ahigh percentage of relapses. Therefore, the emergence of targeted therapy and its use in the Russian Federation since 2021 has made asignificant contribution to the treatment of symptomatic inoperable plexiform neurofibromas.

Detecting Manifestations of Neurofibromatosis: Cutaneous Diagnostic Criteria for NF1 and NF2

Neurofibromatosis is a hereditary condition that causes tumors to form in the brain, spinal cord, and nerve regions. Neurofibromatosis Type 1 (NF1) and Neurofibromatosis Type 2 (NF2) are the two of the most common subtypes. We performed a literature review on Pubmed under the following search and included the 24 most cited papers between 2012 and 2024: “Neurofibromatosis AND (Cutaneous OR Skin) AND (Diagnostic Criteria OR Diagnosis) AND (NF1 OR NF2)”. In our review, both types can manifest cutaneous symptoms, which aid in early detection. Between the two types, NF1 is more common with an estimated prevalence of 1 in 3000, compared to NF2’s 1 in 60,000. NF1 is distinguished by café-au-lait spots, freckling, and neurofibromas; NF2 presents similar to NF1 but may also have characteristic bilateral vestibular schwannomas. While both conditions may exhibit cutaneous manifestations, NF1 primarily presents with such features, whereas NF2 is distinguished by intracranial manifestations. Early detection of cutaneous symptoms is critical for prompt intervention and management of neurofibromatosis. More research is needed to elucidate the detection of neurofibromatosis in clinical practice as differentiation may be challenging.

The NF1 gene mutations and co-mutations in lung adenocarcinomas with brain metastasis.

The co-occurrence of lung adenocarcinoma and brain metastasis remains a significant cause of morbidity and mortality despite advancements in cancer treatment. The activity of neurofibromin, the product of Neurofibromatosis Type 1 gene (NF1), is crucial in regulating the RAS/MAPK pathway. The NF1 somatic mutations are significant in conditions such as melanoma, lung cancer, breast cancer, neuroblastoma, and central nervous system tumors. Therefore, this research aims to uncover the profile of NF1 mutations and co-mutations in patients with brain metastases from lung adenocarcinoma, shedding light on their role in the pathophysiology of metastatic lung cancer. In this study, a total of 131 (31 females, 90 males) patients diagnosed with metastatic lung adenocarcinoma who were examined in the Molecular Pathology Laboratory between 2019 and 2022 were retrospectively analyzed. The NF1 somatic mutations and co-mutations were evaluated using the NGS lung panel on the MiniSEQ NGS platform. The average age of the 131 patients (31 females, 90 males) retrospectively examined in the study was 62.05 years. The ages of the cases included in the study followed a normal distribution according to Kolmogorov-Smirnov test (P = 0.200). Lymph node metastasis was detected in 48 patients (36.6%), while distant organ metastasis was observed in 81 patients (61.83%). Metastases were more frequently seen in males. No statistically significant difference was found between metastases and gender (P > 0.05). Distant organ metastasis (n = 26, 19.8%) and NF1 mutations (n = 8/26, 30.77%) were most commonly observed in the brain. The most common NF1 pathogenic variants in brain metastases were c.2325 + 3A > G (p.M1205fs*12) (n = 6/26, 23.07%) and c.1400C > T (p.T4671) (n = 5/26, 19.23%). There was no statistically significant relationship observed between patients' age, gender, brain metastasis, and NF1 mutation types (respectively, P = 0.98, P = 0.63, and P = 0.87). The mutations that showed the most association with NF1 mutations in brain metastases were PTEN and TP53. Somatic NF1 mutations and co-mutations can play a critical driving force in metastatic lung adenocarcinoma and may contribute to treatment resistance. The mutational landscape of somatic NF1 mutations and co-mutations can provide new insights into the pathophysiology of metastatic lung cancer, especially those that have metastasized to the brain.

Neurofibromatosis type1 adult surveillance form for Austria.

Neurofibromatosis type1 (NF1) is arare autosomal dominant tumor predisposition syndrome with abirth prevalence of approximately 1in 2000-3000 individuals. Management of both benign and malignant tumors arising in individuals with NF1 is demanding and tumors may be difficult to treat. Both standardized and individual surveillance programs are therefore highly important to prevent morbidity and mortality in patients with NF1. The guidelines for the clinical management of NF1 recently proposed by the European Reference Network for Genetic Tumor Risk Syndromes provide the cornerstone of the present surveillance form and were discussed through three rounds of voting and afinal consensus meeting involving experts from five Austrian and one German clinical NF1 centers for adults and one patient organization representative. Subsequently, 31items within 4categories were integrated into the proposed surveillance form for Austria. All recommendations, unless otherwise specified, pertain to primarily asymptomatic patients in routine follow-up. At healthcare transition from pediatric to adult surveillance or the initial visit in adulthood, we suggest athorough clinical, laboratory and radiological examination to obtain abaseline for future diagnostics. To comply with the general screening recommendations in Austria, we suggest extending the frequency of clinical visits from annual to biennial at 50years of age. In cases of clinical dynamics, early follow-up is recommended to facilitate early detection of potential complications. Particular emphasis should be placed on preventive patient education.

MEK inhibitors in maintenance of a postoperative patient with vasculopathy due to neurofibromatosis type I

MEK inhibitors in maintenance of a postoperative patient with vasculopathy due to neurofibromatosis type I

Incidence of Tethered Cord Syndrome in Pediatric Patients With Neurofibromatosis Type 1

ObjectiveThe link between Tethered Cord Syndrome (TCS) and Neurofibromatosis Type 1 (NF1) remains unclear. To date, only two studies have indicated a high occurrence of TCS in the pediatric NF1 patient population. Our study aims to ascertain the incidence of TCS among Chinese pediatric patients with NF1. MethodsA single-institution, 8-year retrospective analysis at a tertiary-level children's hospital was conducted for patients with NF1 who underwent surgery for TCS. The clinical features, imaging characteristics, genetic testing outcomes, and histopathological findings of pediatric NF1 patients with TCS were analyzed. ResultsDuring the study period, a total of 115 pediatric patients were diagnosed with NF1. Among these 115 NF1 patients, 11 individuals, accounting for 9.6% of the sample, were confirmed to have TCS. This rate of occurrence is significantly higher than the incidence rate of TCS in the general population, which stands at 0.17%. All 11 of the pediatric NF1 patients underwent surgery for TCS. Out of the 11 patients who were advised to have tethered cord release surgery, 4 (which is 36.4%) were girls, and the average age of these 11 patients was 8.6 years old, with ages ranging from 2 to 17 years old. The conus medullaris position of the 11 pediatric NF1 patients ranged from L1 to L2, and 10 of them (91%) had a filum terminale lipoma, characterized by high signal intensity on T1-weighted magnetic resonance (MR) images. Another patient was diagnosed with Occult Tethered Cord Syndrome (OTCS). All 11 pediatric NF1 patients exhibited symptoms associated with TCS, such as neuromotor dysfunction, abnormalities in urination, defecation, skeletal system abnormalities, or pain. Eight of the 11 pediatric NF1 patients had undergone genetic testing, which is a crucial part of the diagnostic process for NF1. The histopathological examination of the 11 pediatric NF1 patients who underwent surgery revealed that 10 patients had fatty infiltration of the filum terminale (FT), while the remaining patient exhibited fibrosis of the filum terminale (FT). ConclusionsIn the group of pediatric patients with NF1, the incidence of TCS, presenting to the pediatric neurosurgery clinic for any reason, is significantly higher than that of the general population. However, the pathophysiological relationship between NF1 and TCS is still not clear. It is essential to provide counseling to NF1 patients and their families about the symptoms of TCS to make sure they are aware and can seek the necessary care when needed. This underscores the importance of not only diagnosing NF1 but also staying alert for related conditions like TCS, which may have a higher occurrence in this demographic.

Genetic basis and imaging findings of neurofibromatosis 1 and other somatic overgrowth disorders.

Somatic overgrowth disorders comprise a wide range of rare conditions that present with focal enlargement of one or more tissue types. The PI3K-AKT-mTOR pathway is a signalling pathway that induces angiogenesis and cell proliferation, and is one of the most commonly overactivated signalling pathways in cancer. The PI3K-AKT-mTOR pathway can be up-regulated by genetic variants that code for proteins in this pathway, or down-regulated by proteins that inhibit the pathway. Mosaic genetic variations can result in cells that proliferate excessively in specific anatomical locations. The PIK3CA-related overgrowth spectrum (PROS) disorders include CLOVES syndrome, macrodystrophia lipomatosa, and Klippel-Trenaunay syndrome among many. The neurofibromatosis type 1 (NF1) gene encodes neurofibromin which down-regulates the PI3K-AKT-mTOR pathway. Thousands of pathological variants in the NF1 gene have been described which can result in lower-than-normal levels of neurofibromin and therefore up-regulation of the PI3K-AKT-mTOR pathway promoting cellular overgrowth. Somatic overgrowth is a rare presentation in NF1 with a wide range of clinical and radiological presentations. Hypertrophy of all ectodermal and mesodermal elements has been described in NF1 including bone, muscle, fat, nerve, lymphatics, arteries and veins, and skin. The shared signalling pathway for cellular overgrowth means that these radiological appearances can overlap with other conditions in the PIK3CA-related overgrowth spectrum. The aim of this review is to describe the genetic basis for the radiological features of NF1 and in particular compare the appearances of the somatic overgrowth disorders in NF1 with other conditions in the PIK3CA-related overgrowth spectrum.

Prenatal diagnosis for neurofibromatosis type 1 and the pitfalls of germline mosaics

We report our 5-year experience in neurofibromatosis type 1 prenatal diagnosis (PND): 205 PNDs in 146 women (chorionic villus biopsies, 88% or amniocentesis, 12%). The NF1 variant was present in 85 (41%) and absent in 122 (59%) fetuses. Among 205 pregnancies (207 fetuses), 135 were carried to term (119 unaffected and 16 NF1 affected children), 69 pregnancy terminations (affected fetuses), 2 miscarriages, and 1 in utero death. The majority of PND requests came from parents with sporadic NF1. We describe two PNDs in women with mosaic NF1. In both families, direct PND showed the absence of the maternal NF1 variant in the fetus. However, microsatellite markers analysis showed that the risk haplotype had been transmitted. These rare cases of germline mosaicism illustrate the pitfall of indirect PND. Our study illustrates the crucial consequences of PND for medical and genetic counseling decisions. We also point to the challenges of germline mosaics.

Inner retinal layer thickness alterations in adult and pediatric patients with neurofibromatosis 1

This study compared the thickness of each intraretinal layer in patients with neurofibromatosis 1 (NF1) and controls to analyze the association between intraretinal layer thickness and visual function. The macular spectral-domain optical coherence tomography volumetric dataset obtained from 68 eyes (25 adult eyes, 43 pediatric eyes) with NF1 without optic glioma and 143 control eyes (100 adult eyes, 43 pediatric eyes) was used for image auto-segmentation. The intraretinal layers segmented from the volumetric data included the macular retinal nerve fiber layer (RNFL), ganglion cell-inner plexiform layer (GCIPL), inner nuclear layer, outer plexiform layer, outer nuclear layer, and photoreceptor layer. Cases and controls were compared after adjusting for age, sex, refractive error, and binocular use. The association between retinal layer thickness and visual acuity was also analyzed. The GCIPL was significantly thinner in both adult and pediatric patients with NF1 compared with healthy controls. Average RNFL and GCIPL thicknesses were associated with visual acuity in adult patients with NF1. In pediatric patients, average GCIPL thickness was associated with visual acuity. These results suggest that changes in the inner retinal layer could be a biomarker of the structural and functional status of patients with NF1.

Clinical Outcomes of Carbon Ion Radiation Therapy for Malignant Peripheral Nerve Sheath Tumors

Purposeto investigate outcome and toxicity of patients affected by malignant peripheral nerve sheath tumors (MPNSTs) treated with high-dose carbon ion radiotherapy (CIRT). Patients and methodswe retrospectively analyzed the outcome of 23 patients with MPNST treated between July 2013 and December 2020. Out of these, 13 patients (56.5%) had incompletely resected tumors, 8 patients (34.7%) experienced recurrence after surgery, and 2 patients (8.7%) had unresectable tumors. Before CIRT treatment, 4 patients underwent a second surgery after the first local recurrence (LR), and 1 patient underwent a third surgery for the second local relapse of disease. Six (26%) of patients received neoadjuvant chemotherapy. The most frequent tumor site was brachial plexus (N=9; 39.1%). In five patients (21.7%) neurofibromatosis type 1 (NF1) disorder was found, while 4 patients (17, 4%) had radiation-induced MPNST. The median CIRT prescribed total dose was 69.8 Gy [RBE] (range, 54-76.8) delivered in a median of 16 fractions (range, 15-22). Eleven patients (47.82%) were treated according to a sequential boost protocol with a median prescribed dose to CTV-LR of 45 Gy[RBE] (range, 41.4 – 54). ResultsAfter a median follow-up time of 23 months (range 3-100 months), the OS rates at 1-year and 2-year were respectively: 82.38%, 61.51%. The 1-year and 2-year LRFS rates were respectively: 65.07%, 48.80%; the 1-year and 2-year PFS rates were respectively: 56.37%, 40.99%. No patients showed acute or late Grade 4 toxicity or any treatment-related deaths. Ten patients (43.48%) reported acute toxicities of Grade ≥2: dermatitis in 6 patients, mucositis in 2 patients, peripheral neuropathy in 4 patients. Eight patients (34.78%) reported late toxicities of Grade ≥2, mainly due to loco-regional neuropathy. Conclusionshigh dose CIRT shows favorable local effect with acceptable toxicities in patients with gross residual and LR after surgery, or unresectable malignant peripheral nerve sheath tumors. Advanced treatment modalities such as particle therapy should be considered for MPNSTs.

Co-occurrence of neurofibromatosis type 1, caused by Alu insertion, and 16p13.11 microduplication

BackgroundNeurofibromatosis type 1 (NF1), an autosomal dominant disorder, characterized by a spectrum of diverse neurocutaneous manifestations, is caused by heterozygous pathogenic variants in NF1 gene. While patients with NF1 often exhibit characteristic features, atypical phenotypes can arise, necessitating consideration of differential diagnoses or concurrent pathologies.Case presentationA seven-year-old boy with suspected NF1 underwent clinical evaluation. He presented hallmark café-au-lait spots, axillary freckling, and neurofibromas. Neuroimaging revealed a cranial plexiform neurofibroma. Additionally, he exhibited attention-deficit hyperactivity disorder and developmental delay. Genetic testing identified an Alu insertion variant within the NF1 gene, and subsequent array comparative genomic hybridization detected a 16p13.11 duplication.ConclusionsThis case underscores the intricate molecular bases of NF1 by identifying a rare Alu insertion variant. The patient's neurocognitive challenges and dysmorphic features prompted exploration of a potential overlapping genetic condition. Coexisting genetic disorders have been documented in NF1 patients, emphasizing the necessity of discerning atypical manifestations. The observed 16p13.11 duplication likely contributes to the patient's phenotype, enhancing the precision of diagnosis, prognosis, and genetic counseling.

Cold Atmospheric Plasma Induces Growth Arrest and Apoptosis in Neurofibromatosis Type 1-Associated Peripheral Nerve Sheath Tumor Cells.

Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder resulting from mutations in the NF1 gene. Patients harboring these mutations are predisposed to a spectrum of peripheral nerve sheath tumors (PNSTs) originating from Schwann cells, of which malignant peripheral nerve sheath tumors (MPNSTs) are the deadliest, with limited treatment options. Therefore, an unmet need still exists for more effective therapies directed at these aggressive malignancies. Cold atmospheric plasma (CAP) is a reactive oxygen species (ROS) and reactive nitrogen species (RNS) generating ionized gas that has been proposed to be a potential therapeutic modality for cancer. In this study, we sought to determine the effects of CAP on NF1-associated PNSTs. Utilizing established mouse and human cell lines to interrogate the effects of CAP in both in vitro and in vivo settings, we found that NF1-associated PNSTs were highly sensitive to CAP exposure, resulting in cell death. To our knowledge, this is the first application of CAP to NF1-associated PNSTs and provides a unique opportunity to study the complex biology of NF1-associated tumors.

Greater sphenoid wing reconstruction with 3D printed anatomical intracranial implant for a child with spheno-orbital encephalocele.

Sphenoid wing dysplasia is a characteristic finding in children with neurofibromatosis type 1 (NF1). Some of these children develop proptosis and vision loss secondary to the spheno-orbital encephalocele. A 6-year-old boy presented to us with complaints of painless progressive uni-ocular vision loss and progressive pulsatile proptosis. Imaging revealed spheno-orbital encephalocele into the orbit through the dysplastic posterior orbital wall. 3D printed customized implant was designed and placed to fit the defect. This prevented further herniation of the temporal lobe into the orbit, leading to reduction of proptosis and improvement in vision of the child.

Comparing 3D imaging devices for the measurement of cutaneous neurofibromas in patients with Neurofibromatosis Type 1.

Cutaneous neurofibromas (cNFs) are a major cause of disfigurement in patients with Neurofibromatosis Type 1 (NF1). However, clinical trials investigating cNF treatments lack standardised outcome measures to objectively evaluate changes in cNF size and appearance. 3D imaging has been proposed as an objective standardised outcome measure however various systems exist with different features that affect useability in clinical settings. The aim of this study was to compare the accuracy, precision, feasibility, reliability and accessibility of three imaging systems. We compared the Vectra-H1, LifeViz-Micro and Cherry-Imaging systems. A total of 58 cNFs from 13 participants with NF1 were selected for imaging and analysis. The primary endpoint was accuracy as measured by comparison of measurements between imaging systems. Secondary endpoints included reliability between two operators, precision as measured with the average coefficient of variation, feasibility as determined by time to capture and analyse an image and accessibility as determined by cost. There was no significant difference in accuracy between the three devices for length or surface area measurements (p>0.05), and reliability and precision were similar. Volume measurements demonstrated the most variability compared to other measurements; LifeViz-Micro demonstrated the least measurement variability for surface area and image capture and analysis were fastest with LifeViz-Micro. LifeViz-Micro was better for imaging smaller number of cNFs (1-3), Vectra-H1 better for larger areas and Cherry for uneven surfaces. All systems demonstrated excellent reliability but possess distinct advantages and limitations. Surface area is the most consistent and reliable parameter for measuring cNF size in clinical trials.

The clinical characteristics of 497 children with congenital pseudarthrosis of the tibia

Objective: To investigate the clinical and radiologic characteristics of children with congenital pseudarthrosis of the tibia (CPT) in a single center. Methods: This is a retrospective case series study. According to inclusion and exclusion criteria, clinical data of 497 children(507 limbs) with CPT who were treated at Department of Orthopedics, the Children's Hospital Affiliated to Xiangya School of Medicine, Central South University from January 2011 to December 2020 were collected. Baseline data included gender, age at initial visit, age at onset of symptoms, accompanying symptoms, domicile, whether first treated at our hospital, and treatment-related information such as surgical or conservative treatment, surgical complications, etc., were extracted and analyzed using the health information system. Imaging data of the children, including Crawford classification, bilateral leg lengths, presence of fibular pseudarthrosis, and location of pseudarthrosis along the tibia segment, were analyzed using the Picture Archiving and Communication System. Data were compared using independent sample t test or χ2 tests. Results: Among 497 children with CPT, there were 305 males (61.4%) and 192 females (38.6%). The age at initial visit was (3.6±3.2) years (range: 0.1 to 16.2 years). Neurofibromatosis type 1 (NF1) symptoms were positive in 340 children (68.4%), and negative in 157 children (31.6%). Among NF1-positive children, those with symptoms onset before 1 year of age were significantly more than NF1-negative children (74.1%(252/340) vs. 66.2%(104/157);χ2=9.24, P=0.001), and the proportion of fractures (92.9%,316/340) was significantly higher than that in the NF1-negative group (84.7%,133/157) (χ2=8.33, P=0.004). According to imaging data, Crawford type Ⅳ was the most common type, with 321 limbs (63.3%), followed by type Ⅱ in 100 limbs (19.7%), type Ⅲ in 54 limbs (10.7%) and type Ⅰ in 32 limbs (6.3%). Pseudarthrosis occurred in the proximal third of the tibia in 14 limbs (2.8%), in the middle third in 185 limbs (36.5%), and in the distal third in 308 limbs (60.8%). Seventy-four children (14.9 %) had associated fibular pseudarthrosis. The lateral proximal tibial angle was 86.91°±5.21°(range: 72.17° to 102.08°), and the lateral distal tibial angle was 87.27°±10.73°(range: 51.07° to 128.17°). A total of 421 children (84.7%) underwent surgical treatment with (3.1±2.4) surgeries performed per child (range:0 to 12 surgeries); 76 children (15.3%) received conservative treatment. Postoperative complications mainly included ankle valgus (77 cases), leg length discrepancy (71 cases),refracture (48 cases), osteomyelitis (11 cases), and hardware failure (10 cases). NF1-positive children underwent more surgeries than NF1-negative children ((5.1±2.2)times vs.(2.1±1.8)times;t=14.93,P<0.01). Conclusions: Crawford type Ⅳ is the most common type of CPT in children in this study. CPT predominantly occurs in the middle or distal third of the tibia. The majority of children with CPT experienced symptoms and were seen at outpatient clinics before the age of 3 years. The main surgical complications currently associated with CPT treatment are ankle valgus and leg length discrepancy. Compared with CPT without NF1, children with NF1-positive CPT tend to have earlier symptom onset and may require more frequent treatments.

1760P Impact of adjuvant imatinib on recurrence for neurofibromatosis type 1 (NF1) associated GISTs: An analysis of the RECKGIST cohort from the French NETSARC+ network

1760P Impact of adjuvant imatinib on recurrence for neurofibromatosis type 1 (NF1) associated GISTs: An analysis of the RECKGIST cohort from the French NETSARC+ network

Synergistic effects of combined BET and FAK inhibition against Vestibular Schwannomas in NF2-related Schwannomatosis.

Neurofibromatosis type 2 (NF2) is a rare disorder that causes vestibular schwannomas (VS), meningiomas and ependymomas. To date, there is no FDA approved drug-based treatment for NF2. We have previously identified that BET inhibition can selectively reduce growth of the NF2-null schwannoma and Schwann cells in vitro and tumorigenesis in vivo and, separately, reported that inhibition of Focal Adhesion Kinase 1 (FAK1) via crizotinib has antiproliferative effects in NF2-null Schwann cells. The current study was aimed at determining whether combined BET and FAK inhibition can synergize and to identify the mechanisms of action. A panel of normal and NF2-null Schwann and schwannoma cell lines were used to characterize the effects of combined BET and FAK inhibition in vitro and in vivo using pharmacological and genetic approaches. The mechanism of action was explored by chromatin immunoprecipitation, ChIP-PCR, western blotting, and functional approaches. We find that combined BET and FAK inhibition are synergistic and inhibit the proliferation of NF2-null schwannoma and Schwann cell lines in vitro and in vivo, by arresting cells in the G1/S and G2/M phases of the cell cycle. Further, we identify the mechanism of action through the downregulation of FAK1 transcription by BET inhibition, which potentiates inhibition of FAK by 100-fold. Our findings suggest that combined targeting of BET and FAK1 may offer a potential therapeutic option for the treatment of NF2-related schwannomas.

1761P Clinical description and development of a prognosis score for neurofibromatosis type 1 (NF1) associated GISTs in the RECKGIST cohort: A retrospective study from the French NETSARC+ network

1761P Clinical description and development of a prognosis score for neurofibromatosis type 1 (NF1) associated GISTs in the RECKGIST cohort: A retrospective study from the French NETSARC+ network

50735 Dermatology Access for Patients with Neurofibromatosis Type 1 (NF1): Results of a Survey Utilizing the Children’s Tumor Foundation NF Registry

50735 Dermatology Access for Patients with Neurofibromatosis Type 1 (NF1): Results of a Survey Utilizing the Children’s Tumor Foundation NF Registry