Hospital Visits Associated With Oral Infections in Patients With Neurofibromatosis Type 1: A Register-Based Analysis.

Various forms of oral involvement have been reported in patients with neurofibromatosis 1 (NF1). Here, we analyze register-based associations between NF1 and hospital visits related to oral infections. The Finnish NF1 cohort encompasses all individuals with verified NF1 who have visited the Finnish central and university hospitals in 1987-2011. The Finnish Care Register for Health Care allowed the follow-up of 1349 individuals with NF1, their 1894 siblings without NF1, and 13,870 matched controls for diagnoses related to oral infections in 1998-2014. We observed clearly increased hazards for hospital visits associated with dental caries (ICD-10 K02; NF1 vs. controls, hazard ratio [HR] 4.42, 95% CI 3.23-6.04), diseases of pulp and periapical tissues (K04; HR 3.85, 95% CI 2.68-5.54), and gingivitis and periodontal diseases (K05; HR 3.63, 95% CI 2.37-5.56). In contrast, hospital visits related to diseases of salivary glands (K11), and stomatitis and related lesions (K12) did not show significantly increased hazard in NF1 compared with the controls or the non-NF1 siblings. In conclusion, the findings suggest that hospital visits related to oral infections are relatively common among individuals with NF1. The results highlight the need for early detection, proactive prevention, and timely treatment of oral infections in individuals with NF1.

Successful Treatment of Peripheral Nerve Sheath Tumor-related Pain with Perineural Steroid Injection: a case report.

Pain associated with Neurofibromatosis Type 1 (NF1) is poorly understood. To date, no treatment options have been approved for NF1-related pain. We present the case of a young female NF1 patient with intermittent buttock pain radiating down the leg who presented with positive dural tension signs. The patient was diagnosed with neurofibroma sciatic nerve compression, which was successfully managed with ultrasound-guided perineural steroid injection. There is sparse literature regarding the efficacy of ultrasound-guided perineural steroid injection in NF1 patients for treatment of benign peripheral nerve sheath tumor compressions. This case describes the utility of perineural steroid injections for symptomatic relief of NF1 neurofibroma-related pain. Perineural steroid injections should be considered when neurofibroma-related pain fails to respond to other conservative treatment. Steroid injections provide an alternative to oral medicinal management and avoid the often morbid risks of surgical intervention.

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.

INTRATHECAL BACLOFEN FOR NEUROFIBROMATOSIS RELATED SPINAL CORD INJURY WITH SPASTICITY - A CASE REPORT.

This case presents a 35-year-old male with spinal predominant neurofibromatosis-1 who developed an incomplete spinal cord injury (C3 Asia C) which did not improve despite urgent decompressive surgery for multiple cervical neurofibromas. This report outlines a novel indication for intrathecal baclofen. The patient suffered from lower limb weakness with severe spasticity and required assistance of at least two for all activities. The aim of rehabilitation was to improve overall tone while focusing on independence, mobility and quality of life. After a successful trial of intrathecal baclofen, he underwent implantation of an intrathecal baclofen pump. The dose was gradually increased while he received a progressive programme of stretching and functional rehabilitation therapy. After 6 weeks, his MAS had improved to 1-2/4 and he had progressed to independent transfers, independence for most activities of daily living and was able to discharge to his family home with minimal support.

Neurofibromatosis type 1 is a rare disorder causing various skin, skeletal, and neurological issues, including spinal cord injury due to tumours and severe scoliosis. Current treatment is supportive, with surgery sometimes needed for acute injuries. Spasticity, a common complication, leads to functional impairments and reliance on medications with side effects. Intrathecal baclofen pumps offer a targeted solution, delivering baclofen directly into the spine to reduce side effects. We present a case where a gentleman with neurofibromatosis-1-related spinal cord injury received intrathecal baclofen, coupled with intensive rehabilitation, to enhance comfort and daily independence. This case showcases the potential of intrathecal baclofen in managing spasticity in neurofibromatosis-1-related spinal cord disease.

Survival after resection of malignant peripheral nerve sheath tumors: Introducing and validating a novel type-specific prognostic model.

Background: This study aimed to assess the performance of currently available risk calculators in a cohort of patients with malignant peripheral nerve sheath tumors (MPNST) and to create an MPNST-specific prognostic model including type-specific predictors for overall survival (OS). Methods: This is a retrospective multicenter cohort study of patients with MPNST from 11 secondary or tertiary centers in The Netherlands, Italy and the United States of America. All patients diagnosed with primary MPNST who underwent macroscopically complete surgical resection from 2000 to 2019 were included in this study. A multivariable Cox proportional hazard model for OS was estimated with prespecified predictors (age, grade, size, NF-1 status, triton status, depth, tumor location, and surgical margin). Model performance was assessed for the Sarculator and PERSARC calculators by examining discrimination (C-index) and calibration (calibration plots and observed-expected statistic; O/E-statistic). Internal-external cross-validation by different regions was performed to evaluate the generalizability of the model. Results: A total of 507 patients with primary MPNSTs were included from 11 centers in 7 regions. During follow-up (median 8.7 years), 211 patients died. The C-index was 0.60 (95% CI 0.53-0.67) for both Sarculator and PERSARC. The MPNST-specific model had a pooled C-index of 0.69 (95%CI 0.65-0.73) at validation, with adequate discrimination and calibration across regions. Conclusions: The MPNST-specific MONACO model can be used to predict 3-, 5-, and 10-year OS in patients with primary MPNST who underwent macroscopically complete surgical resection. Further validation may refine the model to inform patients and physicians on prognosis and support them in shared decision-making.

Safety and efficacy of selumetinib in pediatric and adult patients with neurofibromatosis type 1 and plexiform neurofibroma.

BACKGROUND: The MEK inhibitor, selumetinib, reduces plexiform neurofibroma (PN) in pediatric patients with neurofibromatosis type 1 (NF1). Its safety and efficacy in adults with PN and effectiveness in other NF1manifestations (e.g., neurocognitive function, growth reduction, and café-au-lait spots) are unknown. METHODS: This open-label, phase 2 trial enrolled 90 pediatric or adult NF1 patients with inoperable, symptomatic, or potentially morbid, measurable PN (≥ 3 cm). Selumetinib was administered at doses of 20 or 25 mg/m2 or 50 mg q 12 hrs for 2 years. Pharmacokinetics, PN volume, growth parameters, neurocognitive function, café-au-lait spots, and quality of life (QoL) were evaluated. RESULTS: Fifty-nine children and 30 adults (median age, 16 years; range, 3-47) received an average of 22±5 (4-26) cycles of selumetinib. Eighty-eight (98.9%) out of 89 per-protocol patients showed volume reduction in the target PN (median, 40.8%; 4.2%-92.2%), and 81 (91%) patients showed partial response (≥ 20% volume reduction). The response lasted until cycle 26. Scores of neurocognitive functions (verbal comprehension, perceptual reasoning, processing speed, and full-scale IQ) significantly improved in both pediatric and adult patients (P <0.05). Prepubertal patients showed increases in height score and growth velocity (P <0.05). Café-au-lait spot intensity decreased significantly (P <0.05). Improvements in QoL and pain scores were observed in both children and adults. All adverse events were CTCAE grade 1 or 2 and were successfully managed without drug discontinuation. CONCLUSION: Selumetinib decrease PN volume in the majority of pediatric and adult NF1 patients while also showing efficacy in non-malignant diverse NF1 manifestations.

Cafe-au-lait spots with resistant hypertension are an indicator of pheochromocytoma: a rare case report.

This case report is one of the rare cases of bilateral pheochromocytoma associated with neurofibromatosis type 1. The interest lies in the clinical form in which the diagnosis was revealed. We report the case of a 38-year-old woman admitted for severe hypertension resistant to triple therapy. Clinical examination revealed Cafe-au-lait spots, which are pigmented birthmarks that appear as patches on the skin with a light to dark brown colour. More than six spots are present in an estimated 95% of people diagnosed with neurofibromatosis type 1 (NF1). Abdominal computed tomography (CT) showed bilateral adrenal tumor involvement. The diagnosis of pheochromocytoma was made by measuring urinary Vanillylmandelic acid (VMA). The evolution was favorable after the excision of the tumor, with normalization of blood pressure. In conclusion: resistant hypertension with café au lait spots may indicate pheochromocytoma, especially bilateral, suggesting an underlying genetic condition like NF1, warranting systematic screening.

En este reporte se documenta un caso raro de feocromocitoma bilateral asociado a neurofibromatosis tipo 1. El interés radica en la forma clínica en la que se reveló el diagnóstico. Presentamos el caso de una mujer de 38 años que ingresa por hipertensión arterial severa resistente a triple terapia. El examen clínico reveló manchas café con leche, que son marcas de nacimiento pigmentadas que aparecen como manchas en la piel y que son de un color marrón claro a oscuro. Se estima que el 95% de las personas diagnosticadas con neurofibromatosis tipo 1 (NF1) presentan más de seis manchas. La tomografía computarizada (TC) abdominal mostró afectación tumoral suprarrenal bilateral. El diagnóstico de feocromocitoma se realizó mediante la medición del ácido vanilmandélico (VMA) urinario. La evolución fue favorable tras la extirpación del tumor, con normalización de la presión arterial. En conclusión, la hipertensión resistente con manchas café con leche puede indicar feocromocitoma, especialmente si es bilateral, lo que sugiere una afección genética subyacente como la NF1, que justifica un tamizaje sistemático.

Do metabolic deficits contribute to sleep disruption in monogenic intellectual disability syndromes?

Intellectual disability is defined as limitations in cognitive and adaptive behavior that often arise during development. Disordered sleep is common in intellectual disability and, given the importance of sleep for cognitive function, it may contribute to other behavioral phenotypes. Animal models of intellectual disability, in particular of monogenic intellectual disability syndromes (MIDS), recapitulate many disease phenotypes and have been invaluable for linking some of these phenotypes to specific molecular pathways. An emerging feature of MIDS, in both animal models and humans, is the prevalence of metabolic abnormalities, which could be relevant for behavior. Focusing on specific MIDS that have been molecularly characterized, we review sleep, circadian, and metabolic phenotypes in animal models and humans and propose that altered metabolic state contributes to the abnormal sleep/circadian phenotypes in MIDS.

A life-threatening, massive subcutaneous hematoma caused by trauma in a patient with neurofibromatosis type 1: a case report and literature review.

Background: Neurofibromatosis type 1 (NF1) is an autosomal dominant disease that can give rise to the formation of vascular lesions in affected individuals. These lesions, whether occurring spontaneously or as a result of trauma, have the potential to cause severe and even fatal hemorrhage. Case description: We presented a case demonstrating the most extensive hematoma ever documented in a patient with NF1, resulting from a minor trauma. He experienced hemodynamic instability due to severe anemia. Arteriography revealed a rupture in the intercostal artery, which was successfully treated through interventional embolization to stop the hemorrhage. Additionally, we implemented a refined surgical approach, beginning with suturing, followed by the meticulous resection of necrotic and aberrant tissues, thereby markedly diminishing bleeding. Conclusion: Minor trauma may cause severe bleeding in patients with NF1, which can be life-threatening. Timely diagnosis of NF1 and effective hemostatic techniques are key to successful treatment.

Neurofibromatosis type 1 with huge intrathoracic meningoceles misdiagnosed as pleural effusion: A case report and literature review.

BACKGROUND: Neurofibromatosis type 1 is a genetic disease that affects multiple organs and systems, leading to various clinical manifestations. In Neurofibromatosis type 1, rare intrathoracic meningoceles often occur alongside bone dysplasia. These meningoceles contain cerebrospinal fluid and can be mistakenly diagnosed as 'pleural effusion'. CASE PRESENTATION: In this case report, we mistakenly identified 'cerebrospinal fluid' as 'pleural effusion' and proceeded with drainage. This error posed significant risks to the patient and holds valuable implications for the future diagnosis and treatment of similar patients. CONCLUSIONS: In patients with Neurofibromatosis type 1 complicated by spinal deformity, there is a high incidence of intrathoracic meningoceles. Treatment strategies may differ based on the specific features of the lesions, and collaboration among multiple disciplines can significantly improve patient outcomes.

Obstructive Hydrocephalus Due to Aggressive Posterior Fossa Tumor Exhibiting Histological Characteristics of Pilocytic Astrocytoma in Two Adult Neurofibromatosis Type 1 (NF1) Cases.

Neurofibromatosis type 1 (NF1) is an autosomal dominant syndrome caused by germline alteration of the NF1gene. Among various NF1-related manifestations, obstructive hydrocephalus especially in adult NF1 cases is less frequently found. We report two adult NF1 cases exhibiting obstructive hydrocephalus due to an aggressive posterior fossa tumor exhibiting pathological characteristics of pilocytic astrocytoma as NF1-related manifestations. In these two cases, we performed endoscopic third ventriculostomy (ETV) and tumor biopsy as an initial treatment. The initial pathological diagnosis of the tumor is conventional pilocytic astrocytoma. After biopsy both cases revealed rapid tumor growth, therefore, we performed tumor removal, chemotherapy, and radiation therapy during an aggressive clinical course. However, both cases revealed dismal prognosis due to the progression of the tumor in spite of successful management of hydrocephalus by an initial ETV. DNA methylation analysis revealed that the tumor of one case matched high-grade astrocytoma with piloid features (HGAP). Most central nervous system tumors developed in NF1 are less aggressive such as pilocytic astrocytoma; however, recently a few studies revealed that HGAP, which has been a newly introduced malignant tumor in the World Health Organization Classification of Tumors of the Central Nervous System, 5th edition (WHO CNS 5), rarely develops in NF1 cases. These findings suggested that HGAP might be one of the important causes of obstructive hydrocephalus in adult NF1 cases.

The profile of epilepsy and its characteristics in children with neurocutaneous syndromes.

Objectives: The profile of seizures in neurocutaneous syndromes is variable. We aimed to define the characteristics of epilepsy in children with neurocutaneous syndromes. Materials and Methods: Cross-sectional study over 18 months at a tertiary care pediatric hospital, including children with neurocutaneous syndromes aged between 1 and 15 years, using the 2017-International League Against Epilepsy classification. Results: In 119 children with neurocutaneous syndromes, 94 (79%) had epilepsy. In eight children with neurofibromatosis one with epilepsy, 5 (62.5%) had generalized motor tonic-clonic seizures, 1 (12.5%) had generalized motor epileptic spasms, 1 (12.5%) had generalized motor automatism, and 1 (12.5%) had a focal seizure. In 69 children with tuberous sclerosis complex with epilepsy, 30 (43.5%) had generalized motor epileptic spasms, 23 (33.3%) had focal seizures, and nine (13.0%) had generalized motor tonic-clonic seizures. In 14 children with Sturge-Weber syndrome with epilepsy, 13 (92.8%) had focal seizures, and 1 (7.2%) had generalized motor tonic seizures. Statistically significant associations were found between epilepsy and intellectual disability (P = 0.02) and behavioral problems (P = 0.00). Conclusion: Profiling seizures in children with neurocutaneous syndromes are paramount in devising target-specific treatments as the epileptogenesis in each syndrome differs in the molecular pathways leading to the hyperexcitability state. Further multicentric studies are required to unravel better insights into the epilepsy profile of neurocutaneous syndromes.

Histologic correlates of "Choroidal abnormalities" in Neurofibromatosis type 1 (NF1).

Neurofibromatosis type 1 (NF1) is a rare autosomal dominant disorder characterized by proliferation of cells from neural crest origin. The most common manifestations are cutaneous, neurologic, skeletal and ocular. The distinction of NF1 from other syndromes with multiple café-au-lait macules may be difficult in the pediatric age group, and ocular findings, especially Lisch nodules (i.e., melanocytic hamartomas on the irides), are a useful, early diagnostic tool. In recent years, novel ocular manifestations descriptively referred to as "choroidal abnormalities", choroidal "hyperpigmented spots" and "retinal vascular abnormalities" have been recognized in NF1. Choroidal abnormalities (CA) appear as bright patchy nodules that can be best detected with near-infrared ocular coherence tomography imaging (NIR-OCT). Because of their high specificity and sensitivity for NF1, CA have been added as an ocular diagnostic criterion of NF1 as an alternative to Lisch nodules. Although CA are important ocular diagnostic criteria for NF1, the histologic correlates are controversial. We present the postmortem ocular pathology findings of an NF1 patient for whom clinical notes and ocular imaging were available. Findings in this patient included choroidal hyperpigmented spots on funduscopy and retinal vascular abnormalities, both of which have been reported to be closely associated with CA. Histologic examination of the eyes showed multiple clusters of melanocytes of varying sizes in the choroid. Pathologic review of 12 additional postmortem eyes from 6 NF1 patients showed multiple, bilateral choroidal melanocytic aggregates in all eyes. These findings suggest that the CA seen on NIR-OCT and the hyperpigmented spots seen clinically in NF1 patients are manifestations of multifocal choroidal melanocytic clusters, consistent with choroidal melanocytic hamartomas. Lisch nodules, often multiple, were present in all eyes with morphology that differed from the choroidal hamartomas. As such, although CA and Lisch nodules are melanocytic hamartomas, there are clear phenotypical differences in their morphologies.

DRI Triton SS-OCT applied to detect choroidal nodules in paediatric patients affected by NF1.

Purpose: To examine whether image processing of non-mydriatic DRI Triton SS-OCT (Topcon Corporation, Tokyo, Japan) using the red free filter could assess the presence of choroidal nodules and thus include their detection as a diagnostic criterion in neurofibromatosis type 1 (NF1). Material and methods: We included 417 eyes from 210 patients, 377 - from 190 patients diagnosed with NF1 according to the criteria established by the National Institutes of Health Consensus Development Conference (NIH) and 40 from 20 healthy patients as a control group. The mean age was 9.4 years (range 2 years-18 years). All patients had their visual acuity measured by a test according to age, were examined for the presence of lisch nodules and an Optical Coherence Tomography (OCT) of the macular area was performed. All the OCT images were analysed to check if visible nodules could be identified. Results: Ages 14 (95% CI=(9.7,18.3)) and 12 years (95% CI=(9.1,14)) are the cut-off points that best separate those with choroidal nodules with Triton OCT and lisch with slit lamp, respectively, from those without. lisch nodules were detected in 50% of cases of NF1 patients. The presence of choroidal nodules did not present a statistically significant correlation with the occurrence of optic pathway glioma (p = 0.96) nor with the patient's visual worsening (p = 0.072). A statistically significant correlation was observed between the presence of choroidal nodules and the presence of lisch nodules (p < 0.05). Conclusion: The Topcon Triton OCT red free tool would not be a good tool to detect choroidal nodules in patients with NF1 because of its low sensitivity. If the presence of choroidal nodules were to be included in the diagnostic criteria for NF1, it would be convenient to use a device with red and infrared radiations.

Drosophila Contributions towards Understanding Neurofibromatosis 1.

Neurofibromatosis 1 (NF1) is a multisymptomatic disorder with highly variable presentations, which include short stature, susceptibility to formation of the characteristic benign tumors known as neurofibromas, intense freckling and skin discoloration, and cognitive deficits, which characterize most children with the condition. Attention deficits and Autism Spectrum manifestations augment the compromised learning presented by most patients, leading to behavioral problems and school failure, while fragmented sleep contributes to chronic fatigue and poor quality of life. Neurofibromin (Nf1) is present ubiquitously during human development and postnatally in most neuronal, oligodendrocyte, and Schwann cells. Evidence largely from animal models including Drosophila suggests that the symptomatic variability may reflect distinct cell-type-specific functions of the protein, which emerge upon its loss, or mutations affecting the different functional domains of the protein. This review summarizes the contributions of Drosophila in modeling multiple NF1 manifestations, addressing hypotheses regarding the cell-type-specific functions of the protein and exploring the molecular pathways affected upon loss of the highly conserved fly homolog dNf1. Collectively, work in this model not only has efficiently and expediently modelled multiple aspects of the condition and increased understanding of its behavioral manifestations, but also has led to pharmaceutical strategies towards their amelioration.

Functional and Radiological Outcomes of All-Posterior Surgical Correction of Dystrophic Curves in Patients with Neurofibromatosis Type 1.

STUDY DESIGN: A retrospective cohort study. PURPOSE: To determine outcomes following all-posterior surgery using computed tomography navigation, hybrid stabilization, and multiple anchor point techniques in patients with neurofibromatosis type 1 (NF-1) and dystrophic scoliosis. OVERVIEW OF LITERATURE: Previous studies favored antero-posterior fusion as the most reliable method; however, approaching the spine anteriorly was fraught with significant complications. With the advent of computer assisted navigation and multiple anchor point method, posterior only approach is reporting successful outcomes. METHODS: This study included patients who underwent all-posterior surgical deformity correction for dystrophic NF-1 curves. Coronal and sagittal Cobbs angles, apical rotation, and the presence of dystrophic features were evaluated before surgery. Postoperatively, sagittal, coronal, and axial correction, implant position, and implant densities were evaluated. The decline in curve correction and implant-related complications were evaluated at follow-up. Clinical outcomes were evaluated using the Scoliosis Research Society-22 revised index. RESULTS: This study involved 50 patients with a mean age of 13.6 years and a mean follow-up duration of 5.52 years. With a mean coronal flexibility of 18.7%, the mean apical vertebral rotation (AVR), preoperative coronal Cobb angle, and sagittal kyphosis were 27.4°, 64.01°, and 47.70°, respectively. The postoperative mean coronal Cobb angle was 30.17° (p <0.05), and the sagittal kyphosis angle was 25.4° (p <0.05). The average AVR correction rate was 41.3%. The correction remained significant at the final mean follow-up, with a coronal Cobb angle of 34.14° and sagittal kyphosis of 25.02° (p <0.05). The average implant density was 1.41, with 46% of patients having a high implant density (HID). The HID had a markedly higher mean curve correction (29.30° vs. 38.05°, p <0.05) and a lower mean loss of correction (5.7° vs. 3.8°, p <0.05). CONCLUSIONS: Utilizing computer-assisted navigation, hybrid instrumentation, and multiple anchor point technique and attaining high implant densities, this study demonstrates successful outcomes following posterior-only surgical correction of dystrophic scoliosis in patients with NF-1.

Ressecção do tumor e colocação de enxerto de pele parcial no couro cabeludo em um paciente com neurofibromatose tipo 1 / Tumor resection and partial skin graft placement on the scalp in a patient with Neurofibromatosis type 1

A neurofibromatose tipo 1 (NF1) é um distúrbio neurocutâneo hereditário no qual se formam tumores no sistema nervoso (neurofibromas). Os neurofibromas são os tumores benignos mais comuns na NF1. O tipo, o tamanho, o número e a localização dos neurofibromas devem ser considerados para a escolha do tratamento. Apresentamos um caso de NF1, no qual foi realizada uma ampla ressecção do couro cabeludo devido à presença de múltiplos neurofibromas. Associado a isso, a reconstrução foi realizada com retalhos de avanço mais autoenxerto de pele parcial, com resultados favoráveis e boa cobertura das áreas onde os tumores foram removidos.

Neurofibromatosis type 1 (NF1) is an inherited neurocutaneous disorder in which tumors form in the nervous system (neurofibromas). Neurofibromas are the most common benign tumors in NF1. The type, size, number, and location of the neurofibromas should be considered for the choice of treatment. We present a case of NF1, in which a wide scalp resection was performed due to the presence of multiple neurofibromas. Associated with this, reconstruction was performed with advancement flaps plus partial skin autograft with favorable results and good coverage of the areas where the tumors were removed.

Whole-Body Positron Emission Tomography with 18F-Fluorodeoxyglucose/Magnetic Resonance Imaging as a Screening Tool for the Detection of Malignant Transformation in Individuals with Neurofibromatosis Type 1.

Malignant peripheral nerve sheath tumors (MPNSTs) are the leading cause of death in patients with neurofibromatosis type 1. They can result from premalignant neurofibromas, including neurofibromas with atypia and atypical neurofibromatous neoplasms of uncertain biologic potential. Some phenotypic characteristics have been described as associated with their development. The aim of this study was to outline our use of whole-body positron emission tomography with 18F-fluorodeoxyglucose/magnetic resonance imaging in adults with neurofibromatosis type 1, especially in the screening of asymptomatic individuals with a higher risk of developing an MPNST, and to study its impact on neurofibroma classification (malignant vs premalignant) and MPNST staging over time. Individuals with neurofibromatosis type 1 who underwent a positron emission tomography with 18F-fluorodeoxyglucose/magnetic resonance imaging between 2017 and 2021 were included, analyzing separately the screened population. Maximum standard uptake value and diffusion-weighted imaging were assessed. Biopsy/surgery confirmed the diagnosis. In all, 345 positron emission tomography with 18F-fluorodeoxyglucose/magnetic resonance imaging were performed in 241 patients, including 149 asymptomatic (62%) but at-risk patients. Eight MPNSTs in 8 screened individuals (5%), 6 neurofibromas with atypia in 4 individuals (3%), and 29 atypical neurofibromatous neoplasms of uncertain biologic potential in 23 individuals (15%) were diagnosed. Over time, the proportion of grade 3 MPNST and the malignant/premalignant ratio in screened individuals significantly decreased (P = .03 and P < .001, respectively). This study emphasizes the diagnostic and screening performances of whole-body positron emission tomography with 18F-fluorodeoxyglucose/magnetic resonance imaging in adults with neurofibromatosis type 1.