Selumetinib for children with neurofibromatosis type 1 and plexiform neurofibromas: A plain language summary of SPRINT

WHAT IS THIS SUMMARY ABOUT?

This summary describes a publication about a study called SPRINT. The SPRINT study included 50 children with neurofibromatosis type 1 (NF1) and plexiform neurofibroma (PN) that could not be removed with surgery. PNs are tumors that grow along nerves and can cause various problems for children, such as pain, changes to appearance, and muscle weakness. In SPRINT, the study team wanted to learn whether a medication called selumetinib was able to shrink the PN caused by NF1 (also known as NF1-related PN), and if shrinking PNs helped relieve children of the problems caused by it. To assess how selumetinib might help, children had scans to measure the size of their PN, completed questionnaires, and had a variety of other tests done by their doctor. Their caregivers also completed questionnaires about their child. The children took selumetinib capsules twice a day on an empty stomach.

WHAT WERE THE RESULTS?

The results showed that selumetinib was able to shrink the PN for most children (68%). The results also showed that the problems caused by the children's PNs mostly improved while on selumetinib treatment. SPRINT also showed that the side effects of selumetinib were mainly mild and could be managed by doctors.

WHAT DO THE RESULTS MEAN?

Before SPRINT, there were not many treatment options for children with NF1 and PN as there were no medications that had been shown to shrink PN, and surgery was not always possible. SPRINT showed that this medication shrinks most PNs and could help children with NF1 and PN. In April 2020, selumetinib was approved by the US Food and Drug Administration (FDA) because of the results of SPRINT. Selumetinib was the first and, as of February 2024, is the only medicine that can be prescribed by doctors to help children with NF1-related PN. Clinical Trial Registration: NCT01362803 (SPRINT) (ClinicalTrials.gov).

Association of plexiform and diffuse neurofibromas with malignant peripheral nerve sheath tumor in NF I patients: a whole-body MRI assessment

OBJECTIVE

The aim of this study is to evaluate neurofibromatosis type 1 (NF1) patients with whole-body MRI (WBMRI) to investigate the frequency of plexiform neurofibromas (pNFs), diffuse neurofibromas (dNFs), and malignant peripheral nerve sheath tumors (MPNSTs).

MATERIALS AND METHODS

In this retrospective cross-sectional study, between the years 2015 and 2023, 83 consecutive patients with known NF1 underwent a total of 110 WBMRI screenings for MPNST using a standardized institutional protocol. The lesions are categorized as discrete lesions, pNFs, dNFs, and MPNSTs. Histopathology served as the reference standard for all MPNSTs.

RESULTS

Among the 83 patients analyzed, 53 (64%) were women and 30 were men (36%) of ages 36.94±14.43 years (range, 15-66 years). Of the 83 patients, 33 have a positive family history of NF1 and positive genetic studies. Seven of 83 (8%) have only dNF, 20/83 (24%) have pNF, 28/83 (34%) have both dNF and pNF, and 28/83 (34%) have neither. Of the 83 patients, eight (9.6%) were diagnosed with nine total MPNSTs. Age range for patients with MPNSTs at time of diagnosis was 22-51, with an average age of 33.4 years. Only one MPNST (11%) developed from underlying pNF 4 years after WBMRI along the right bronchial tree. Three of eight (37.5%) patients with MPNST died within 5 years of pathologic diagnosis.

CONCLUSION

This study suggests the absence of a predisposition for development of MPNST from pNFs and dNFs in the setting of NF1. As such, these lesions may not need special surveillance compared to discrete peripheral nerve sheath tumors.

The PlexiQoL, a patient-reported outcome measure on quality of life in neurofibromatosis type 1-associated plexiform neurofibroma: translation, cultural adaptation and validation into the Dutch language for the Netherlands

BACKGROUND

Half of the patients with Neurofibromatosis type 1 (NF1) develop one or more tumours called plexiform neurofibromas, which can have a significant impact on Quality of Life (QoL). The PlexiQoL questionnaire is a disease-specific QoL measure for adults with NF1-associated plexiform neurofibromas. The aim of this study was to adapt and validate a Dutch version of the PlexiQoL for the Netherlands.

METHODS

The PlexiQoL was translated using the dual-panel methodology, followed by cognitive debriefing interviews to assess face and content validity. The psychometric properties were evaluated by administering the questionnaire on two separate occasions to a sample of adults with NF1 and plexiform neurofibromas. Feasibility was evaluated by the presence of floor/ceiling effects. Reliability was assessed by evaluating Cronbach's alpha coefficient and test-retest reliability, using Spearman's rank correlation coefficients. Mann-Whitney U tests were used to check for known group validity. The Nottingham Health Profile (NHP) questionnaire was used as comparator questionnaire to evaluate convergent validity.

RESULTS

The translation and cognitive debriefing interviews resulted in a Dutch version of the PlexiQoL that reflected the original concept and underlying semantic meanings of the UK English version. Forty participants completed the validation survey. The Dutch PlexiQoL demonstrated excellent internal consistency (Cronbach's α 0.825) and test-retest reliability (Spearman correlation coefficient 0.928). The questionnaire detected differences in PlexiQoL scores between participants based on self-reported general health and disease severity. Convergent validity was confirmed for relevant NHP subsections.

CONCLUSIONS

The Dutch PlexiQoL demonstrated excellent psychometric properties and can be reliably used to measure plexiform neurofibroma-related QoL in adults with NF1 in the Netherlands.

Use of the subfascial plane in debulking an extensive lower extremity plexiform neurofibroma: A case report

INTRODUCTION

Plexiform neurofibromas (PNs) are characterized by their diffuse masses with tortuous expansion along nerve branches. While surgery is the primary management for PNs, the optimal surgical approach remains unestablished.

CASE PRESENTATION

A 35-year-old lady presented with a large hanging mass covering the medial aspect of the thigh and the leg. It caused discomfort, disfigurement, and occasional pain. The patient was planned for the debulking surgery under spinal anesthesia. Incisions were given on the normal-looking skin adjacent to the mass, through the skin layers, subcutaneous tissue and deep fascia until the muscles were seen. The mass was then approached and elevated in the subfascial plane (relatively avascular). Large, dilated, dense tortuous vessels could be seen in the suprafascial and subcutaneous planes. Maximum area that could be removed was marked and excised. The normal contour of the left lower extremity was restored close to achieving a thigh and a leg lift.

DISCUSSION

PNs pose surgical challenges due to their vascularity and difficult locations. The subfascial debulking approach presented in the case aims to reduce intraoperative hemorrhage by avoiding highly vascular areas and preventing entry into blood sinuses within the neurofibromatous tissue. This technique also minimizes the risk of inadvertent injury to nearby neurovascular structures.

CONCLUSION

The proposed subfascial approach, significantly reduces intraoperative hemorrhage during the debulking of a PN.

Case report: Remarkable efficacy of negative-pressure wound therapy in giant lower extremity elephantiasis neuromatosa for vascularization, skin grafting, and fluid control

INTRODUCTION AND IMPORTANCE

Neurofibromatosis type 1 is a benign peripheral nerve tumor, often manifests as plexiform neurofibroma that may cause severe dysfunction, pain, and disfigurement. Bleeding has been reported as a complication of plexiform neurofibroma due to vascular fragility and vasculopathy that may develop into life-threatening bleeding especially after excision procedure. Consequently, post excision complications also include dehiscence and infection.

CASE PRESENTATION

We report a 23-year-old male with elephantiasis of the left lower extremity due to giant plexiform neurofibroma who underwent preoperative embolization followed by serial surgical mass reduction. There were postoperative complications consisting of hematoma, wound dehiscence, and infection.

CLINICAL DISCUSSION

Negative pressure wound therapy is often used to accelerate wound healing, including infected wounds. However, negative pressure wound therapy has been a debatable modality for wound care of neurofibroma due to reported risks of profuse bleeding during its use.

CONCLUSION

In this case, despite the size, negative-pressure wound therapy has shown good results for infected neurofibroma wounds and as an adjunct as wound dressing for defect closure of neurofibroma with split-thickness skin graft.

Neurofibromatosis type 1-associated plexiform neurofibromas of the neck: topography of lesions and surgical treatment data of 69 patients

PURPOSE

Plexiform neurofibromas (PNF) are rare tumors arising from peripheral nerve sheath cells. PNF are a hallmark in patients with neurofibromatosis type 1 (NF1), a tumor predisposition syndrome. PNF often grow invasively and destructively, what may complicate surgical treatment. Data on frequency, location, and surgical procedures of patients with NF1-associated FPNF are scarce. This study provides treatment data of NF1 patients.

METHODS

Localization and treatment data of 69 NF1 patients with neck PNF were analyzed. Frequency of lesions was recorded in coded colors on schematic neck drawings.

RESULTS

The tumors showed no side preference, were located in the entire area under investigation, and did not respect anatomical units/dermatomes. However, the sternocleidomastoid region was particularly frequently affected. The mean number of surgical measures per patient was 1.33. Complications were extensive swelling, hematoma, and bleeding. Histological assessment usually confirmed the clinical assessment of neoplasm. However, histologic differentiation of PNST reveals differences in between tumors that have been unified in clinical assessment as PNF.

CONCLUSION

The color-coded, schematic overview of the frequency distribution of surgical neck interventions in NF1 patients with PNF proved a useful tool to gain assessment of preferred treatment needs. The imaging procedure may be suitable for controlling the external aspect of natural tumor development (growth, effects of aging) in the same way as the documentation of the post-surgical course. Treatment plans for patients with these tumors should consider that repeated interventions may be necessary to achieve a longer-term stable result.

Giant gluteal and vesical plexiform neurofibromas in a patient with neurofibromatosis type 1: a case report

BACKGROUND

Neurofibromatosis type 1 is a neurocutaneous genetic disorder caused by mutations in the NF1 gene, resulting in the formation of benign tumors called neurofibromas. The most common type of tumor seen in patients with neurofibromatosis type 1 is the slow-growing and benign neurofibroma, with a subtype called plexiform neurofibroma being particularly common and causing pain, functional impairment, and cosmetic disfigurement.

CASE PRESENTATION

We report the case of a 20-year-old North African female patient with a history of neurofibromatosis type 1 who presented with a growing mass in her right gluteal region, which was later diagnosed as a giant cutaneous neurofibroma. Imaging studies revealed infiltration in several regions, including the urinary bladder wall, resulting in significant bilateral hydronephrosis. The patient is currently being monitored, and no excisional procedures are planned.

CONCLUSIONS

Neurofibromatosis type 1 can cause a variety of clinical symptoms, including the development of large plexiform neurofibromas. It is important to closely monitor patients with neurofibromatosis type 1 for the early detection of neurofibromas. Early detection and prompt surgical intervention are essential for preventing complications.

Isolated Sacrococcygeal Plexiform Neurofibroma in a Child

This case report describes a 4-year-old girl with an isolated neurofibroma in the sacrococcygeal region. Although initially resembling sacrococcygeal teratoma, histopathology revealed a benign nerve sheath tumor. Wide local excision was performed, and the final diagnosis was plexiform neurofibroma. Diagnostic challenges in rare childhood tumors require stepwise evaluation and multidisciplinary team discussions.

Management of Central and Peripheral Nervous System Tumors in Patients with Neurofibromatosis

Neurofibromatosis type I (NF1), neurofibromatosis type 2 (NF2), and schwannomatosis represent a diverse group of genetic tumor predisposition syndromes with a shared feature of tumors affecting the peripheral nerve sheaths. PURPOSE OF REVIEW: Many advancements have been made in understanding the biologic underpinnings of these conditions, and in 2016 the first drug was approved by the FDA to treat pediatric symptomatic unresectable plexiform neurofibromas. RECENT FINDINGS: Mek inhibitors have provided a much-needed therapeutic avenue for NF1 patients with unresectable plexiform neurofibromas (PN), both for reduction of tumor bulk and for improvement in symptoms. Selumetinib is the first FDA approved drug for PN, but is only approved for children. Some research suggests that alternative Mek inhibitors and other mixed tyrosine kinase inhibitors may have better efficacy in adults. Vascular endothelial growth factor (VEGF) inhibitor bevacizumab can prolong hearing and delay the need for surgery in NF2 patients with bilateral vestibular schwannomas. This article provides an update regarding considerations and approaches when treating the tumors associated with the neurofibromatoses (NF), including risk and prognosis metrics, clinical trial results, surgical techniques, and radiation therapy recommendations.

Plexiform neurofibroma (Hamartoma) of the median nerve: A two-case report

Plexiform neurofibroma is a benign peripheral nerve-sheath tumor, rarely involving major nerves of the extremities. In the literature, there are no clear treatment strategies for plexiform neurofibroma of major peripheral nerves. Our experience encountered two patients with plexiform neurofibroma of the median nerve, presenting with a palmar mass and symptoms of carpal tunnel compression. Preoperatively, plexiform neurofibroma was diagnosed on MRI and clinical examination. Both patients also experienced significant neurological deterioration, with finger numbness and increased nerve/tumor size. Potential malignant transformation was also considered. For these reasons, resection of the involved area of the nerve and repair were indicated. In both patients, intraoperative pathological diagnosis was plexiform neurofibroma. The 45-year-old male patient refused further surgery after carpal tunnel release, which was performed under axillary block. One year postoperatively, nerve compression symptoms decreased moderately. In the other patient, a 7-year-old boy, a significantly enlarged area of the median nerve was resected, and neurorrhaphy was performed. One year postoperatively, median nerve motor-sensory functions recovered completely. Four years postoperatively, no enlargement of the residual tumor was observed.

Plexiform Schwannoma of Digital Nerve

Plexiform schwannoma is an uncommon benign tumour that grows in a plexiform pattern. We report a 47-year-old man with a mass on the palmar aspect of the metacarpophalangeal joint of the right index finger that had been growing gradually for more than 10 years. The mass was palpated from the distal carpal tunnel to the ulnar aspect of the proximal interphalangeal joint of the index finger, with tingling and numbness sensation. The tumour was a multinodular tumour involving the first common palmar digital nerve to the ulnar proper palmar digital nerve. It was resected and reconstructed with a sural nerve graft. Plexiform schwannoma is rare in the digital nerve, with only six cases reported. Generally, classic schwannomas can be enucleated without causing neurologic deficits; however, plexiform schwannoma may require nerve resection. There have been reports of recurrence of plexiform schwannoma; definitive resection and long-term follow-up are necessary. Level of Evidence: Level V (Therapeutic).

Shedding New Light: Novel Therapies for Common Disorders in Children with Neurofibromatosis Type I

Neurofibromatosis type I (NF1) is a common dominantly inherited disorder, and one of the most common of the RASopathies. Most individuals with NF1 develop plexiform neurofibromas and cutaneous neurofibromas, nerve tumors caused by NF1 loss of function in Schwann cells. Cell culture models and mouse models of NF1 are being used to test drug efficacy in preclinical trials, which led to Food and Drug Administration approval for use of MEK inhibitors to shrink most inoperable plexiform neurofibromas. This article details methods used for testing in preclinical models, and outlines newer models that may identify additional, curative, strategies.

Neurofibromatosis Type 1-Associated Plexiform Neurofibromas of the Face and Adjacent Head Regions: Topography of Lesions and Surgical Treatment Data of 179 Patients

Introduction

Facial plexiform neurofibromas (FPNF) are rare tumors frequently diagnosed in patients with neurofibromatosis type 1 (NF1), a tumor predisposition syndrome. FPNF often grows invasively and destructively, which may complicate surgical treatment. Data on the frequency, location, and surgical procedures of patients with NF1-associated FPNF are scarce. This study provides treatment data from a nationally networked reference center for the treatment of NF1 patients.

Material and Methods

The localization and treatment data of 179 NF1 patients with FPNF were analyzed. Photographically documented tumors of the study area, further determined by imaging, were manually transferred to a facial scheme and digitized. The digitized registrations of the facial extensions of the tumors of each patient were overlaid in a single image (Photoshop™), so that the file of the facial scheme contained the sum of the tumor localization. Finally, the frequency of tumor localization was indicated with a color code. The frequency of tumor extension-related coded colors was applied to outline the lesions' topography on schematic face drawings (heat map).

Results

The distribution of the tumors showed no side preference. The need for the treatment of patients with orbital/periorbital manifestations became evident in the graphic representations. Tumors do not respect anatomical units. However, the classification of the face according to dermatomes, especially the trigeminal nerve, offers indications of tumor spread and guides treatment planning. The mean number of surgical measures per patient was 2.21 (median: 1). Extensive swelling, hematoma, and delayed wound healing were all common postoperative complications.

Conclusion

The color-coded, schematic overview of the frequency distribution of cutaneous tumor spread in NF1 patients with FPNF illustrates the importance of orbital/periorbital and cheek tumor manifestations in patients' treatment needs. The imaging procedure is suitable for controlling natural tumor growth in the same way as the documentation of the post-surgical course. Repeated interventions in the region are included in surgical planning of the progressing tumor disease.

Treatment decisions and the use of MEK inhibitors for children with neurofibromatosis type 1-related plexiform neurofibromas

Neurofibromatosis type 1 (NF1), the most common tumor predisposition syndrome, occurs when NF1 gene variants result in loss of neurofibromin, a negative regulator of RAS activity. Plexiform neurofibromas (PN) are peripheral nerve sheath tumors that develop in patients with NF1 and are associated with substantial morbidity and for which, until recently, the only treatment was surgical resection. However, surgery carries several risks and a proportion of PN are considered inoperable. Understanding the genetic underpinnings of PN led to the investigation of targeted therapies as medical treatment options, and the MEK1/2 inhibitor selumetinib has shown promising efficacy in pediatric patients with NF1 and symptomatic, inoperable PN. In a phase I/II trial, most children (approximately 70%) achieved reduction in tumor volume accompanied by improvements in patient-reported outcomes (decreased tumor-related pain and improvements in quality of life, strength, and range of motion). Selumetinib is currently the only licensed medical therapy indicated for use in pediatric patients with symptomatic, inoperable NF1-PN, with approval based on the results of this pivotal clinical study. Several other MEK inhibitors (binimetinib, mirdametinib, trametinib) and the tyrosine kinase inhibitor cabozantinib are also being investigated as medical therapies for NF1-PN. Careful consideration of multiple aspects of both disease and treatments is vital to reduce morbidity and improve outcomes in patients with this complex and heterogeneous disease, and clinicians should be fully aware of the risks and benefits of available treatments. There is no single treatment pathway for patients with NF1-PN; surgery, watchful waiting, and/or medical treatment are options. Treatment should be individualized based on recommendations from a multidisciplinary team, considering the size and location of PN, effects on adjacent tissues, and patient and family preferences. This review outlines the treatment strategies currently available for patients with NF1-PN and the evidence supporting the use of MEK inhibitors, and discusses key considerations in clinical decision-making.

Web in the Neck - An Interesting Case Report

Lateral neck masses are common in children, ranging from simple benign diseases to pathologies with malignant potential. Plexiform neurofibromas are extremely rare peripheral nerve sheath tumours involving multiple nerve sheath fascicles. They are typically seen in the paediatric population, with the majority affecting the craniofacial area and neck. Due to the close clinical and histological resemblance with other benign neck lesions such as lymphadenitis and branchial cysts, these cases can often go misdiagnosed. We describe a lesion in a young girl who presented with a progressive lateral neck swelling and how it was managed.

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.

Giant Perineal Plexiform Neurofibroma in an 8-Year-Old African Male

The perineal presentation of plexiform neurofibroma is exceptional, with only two cases reported to date. We present an 8-year-old African male with a large perineal tumor of years of evolution. He had no associated symptoms. Café au lait stains were observed on examination, without other findings of relevance. The patient had no preoperative radiological studies. Partial excision of the lesion was performed. Histopathological study of the specimen revealed a plexiform neurofibroma. The lack of diagnostic suspicion due to the atypical nature of the location, the anatomical complexity of surgical resection and the potential urological and rectal involvement make this lesion a diagnostic-therapeutic challenge. Among the differential diagnoses, schwannoma, congenital lipoma, hamartoma and lipoblastoma should be considered.

Inhibition of YAP Sensitizes the Selumetinib Treatment for Neurofibromatosis Type 1 Related Plexiform Neurofibroma

Background: Targeted therapy of Neurofibromatosis type 1 (NF1) related plexiform neurofibroma (pNF) aiming at MEK molecule has not demonstrated a convincing result for complete disease inhibition, probably due to other signal pathways crosstalk. Our previous study revealed an increased nuclear translocation of YAP molecule in NF1 related pNF. Herein, we decided to further investigate the therapeutic relations of YAP interference during the MEK treatment against NF1 related pNF. Methods: By means of selumetinib (MEK-inhibitor), RNA-sequencing was firstly performed to identify the changes of signal pathways in pNF Schwann cells, which was probably related to YAP regulation. Nuclear-cytoplasmic fractionation and western blotting were performed to show the intracellular YAP changes under selumetinib treatment. Thirdly, a series of in vitro assays were performed including flow cytometry, CCK-8, and colony/sphere formation under dual treatment of selumetinib and verteporfin (YAP-inhibitor). In addition, Chou-Talalay method was adopted to evaluate the synergistic inhibiting effects of such drug combination. Xenograft study was also used to detect the combining effects in vivo. Results: RNA-sequencing revealed that selumetinib treatment might be associated with the undesirable activation of Hippo pathway in NF1 related pNF tumor cells, which might reduce its pharmaceutic effects. Next, nuclear-cytoplasmic fractionation and further studies demonstrated that selumetinib could promote the nuclear translocation and transcriptional activation of YAP in vitro, which might cause the aforementioned resistance to selumetinib treatment. Additionally, when combined treatments were performed based on verteporfin and selumetinib, synergistic effects were observed on cytotoxicity of NF1 related pNF tumor cells in vitro and in vivo xenograft models. Conclusion: YAP inhibition can effectively sensitize NF1 related pNF tumor cells to selumetinib. Dual targeting of YAP and MEK might be a promising therapeutic strategy for treating NF1 related pNF.

Imaging characteristics of orbital peripheral nerve sheath tumors: Analysis of 34 cases

BACKGROUND

Peripheral nerve sheath tumors (PNSTs), a rare group of neoplasms in the orbit, comprise only 4% of all orbital tumors. At present, there are very few studies detailing the features of these tumors identified using imaging technology.

AIM

To compare the differences in location, morphology, magnetic resonance imaging (MRI) signal intensity/computed tomography (CT) value, and enhancement degree of tumors of different pathological PNSTs types.

METHODS

Clinical, pathological, CT, and MRI data were analyzed retrospectively in 34 patients with periorbital sheath tumors diagnosed using histopathology from January 2013 to August 2021.

RESULTS

Among 34 cases of orbital peripheral nerve sheath tumors, 21 were schwannomas, 12 were neurofibromas, and 1 was a plexiform neurofibroma. Common clinical symptoms presented by patients with these types of tumors include eyelid swelling, exophthalmos, and limited eye movement. Schwannomas mostly occur in the intramuscular space with small tumor volume and rare bone involvement. Neurofibromas develop in the extrapyramidal space with larger tumor volume and more bone involvement. Radiologically, schwannomas and neurofibromas are characterized by regular morphology and uneven density and signal. One case of plexiform neurofibroma showed tortuous and diffuse growth along the nerve, with a worm-like appearance on imaging.

CONCLUSION

Different pathological types of orbital peripheral nerve sheath tumors have unique imaging characteristics. Comprehensive consideration of the patient's clinical and imaging manifestations is of great value in the diagnosis of orbital peripheral nerve sheath tumors.

RETRACTED: A case report of a 4-year-old girl with neurofibromatosis type 1

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Authors. A diagnostic discordance in the original pathology reports has been noticed and requires further evaluation, therefore the paper will be retracted.

Plexiform neurofibroma of the cauda equina with follow-up of 10 years: A case report

BACKGROUND

Plexiform neurofibromas are extremely rarely found in the region of cauda equina and can pose a significant challenge in the diagnostic and management sense. To our knowledge, only 7 cases of cauda equina neurofibromatosis (CENF) have been reported up-to-date.

CASE SUMMARY

We describe a case of a 55-year-old man with a 10 years history of progressive lower extremities weakness and bladder dysfunction. Before presenting, patient was misdiagnosed with idiopathic polyneuropathy. Lumbar spine MRI revealed a tortuous tumorous masses in the cauda equina region, extending through the Th12-L4 vertebrae. The patient underwent Th12-L3 Laminectomy with duraplasty. During the operation, the most enlarged electroneurographically silent nerve root was resected, anticipating inadequate decompression if nerve root was spared. The patient’s neurological condition improved post-operatively, but urinary retention became the major complaint. We provide a follow-up period of 10 years. During this time, the patient’s condition progressively worsened despite extensive decompression. The consequent MRI scans showed progressive enlargement of cauda equina roots and increasing lumbar stenosis, predominantly affecting L3-L4 segment. During the follow-up 8 years after the operation, the patient complained of worsening lower extremities sensorimotor function and neurogenic claudication. Subsequent MRI revealed lumbar spine stenosis at the level of L3-L4, requiring further decompression. The patient underwent a second surgery involving L4-L5 Laminectomy with duraplasty and L2-L5 transpedicular fixation. The post-operative period was uneventful. Latest follow-up 18 mo after the second surgery revealed substantial improvement in patient’s well-being.

CONCLUSION

CENF should be kept in mind during the differential diagnostic work-up for polyneuropathies. Management with an extensive decompression, duraplasty and primary spinal fixation represents a rational approach to achieve a sustained symptomatic improvement and superior overall outcome.

Plexiform neurofibromatosis of the liver: an extremely rare case

Herein, we report an extremely rare case of histopathologically proven neurofibromatosis of the liver. A 15-year-old male, a known case of type I neurofibromatosis (NF1), referred to our hospital with a complaint of right upper quadrant pain. He had a café-au-lait spot and positive family history of NF1 in his mother. Laboratory data was within normal limits, and computed tomography (CT) revealed a large predominantly less attenuated infiltrative liver mass along the porta hepatis with extension to both lobes of the liver. Magnetic resonance imaging showed a large hypo-signal mass in T1-weighted images and hypersignal lesion in T2-sequences with faint enhancement, periportal distribution, and encasing of major branches of the portal vein without evidence of narrowing and invasion. A CT-guided biopsy was taken from both liver lobe lesions, and pathological diagnosis of the biopsy specimens confirmed plexiform neurofibromas of the liver. According to the extensive intrahepatic extension and periportal infiltration, the mass was unrespectable. Radiologists need to be familiar with the typical imaging features of the uncommon hepatic neoplasms. If imaging findings are not typical or diagnostic, a further biopsy should be performed again.

Clinical and humanistic burden among pediatric patients with neurofibromatosis type 1 and plexiform neurofibroma in the USA

PURPOSE

To assess clinical and humanistic burden among pediatric patients with neurofibromatosis type 1 (NF1) and plexiform neurofibroma (PN) in the USA.

METHODS

NF1-PN patients aged 8-18 years (treatment-naïve or ≤ 1 month of selumetinib treatment) and their caregivers and caregivers of similar patients aged 2-7 years were recruited through the Children's Tumor Foundation to participate in an online cross-sectional survey (December 2020-January 2021). Caregivers provided data on patients' demographic and clinical characteristics and burden of debulking surgeries. Patients and caregivers provided self-reported or proxy responses to health-related quality of life (HRQoL) questions using validated instruments.

RESULTS

Sixty-one patients and 82 caregivers responded to the survey. Median (range) age of patients was 11.5 (3-18) years, and 53.7% were female. Most were treatment-naïve (97.6%), with NF1-PN diagnosis for > 5 years (68.3%). Most patients (59.8%) had > 1 PN and 11.0% reporting > 5 PNs. Common NF1-PN symptoms included pain (64.6%), disfigurement (32.9%), and motor dysfunction (28.0%). Patients and caregiver proxies reported low overall HRQoL and reduced physical, emotional, social, and school functioning. Patients also reported considerable pain severity, interference, daily activity impairments, and movement difficulty. Few patients had received complete resections of their tumors (12.2%). 39.0% reported ≥ 1 debulking surgery, among whom, 15.6% had complications, and debulking surgery-related hospitalizations were common (53.1%).

CONCLUSIONS

The clinical and humanistic burden among pediatric NF1-PN patients is substantial. While debulking surgeries are used for symptom management, they are associated with considerable clinical sequelae. Results highlight a need for improved disease management strategies.

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.

Neurofibromatosis type 1 presenting with retinal detachment and laryngeal plexiform neurofibroma in a toddler

Purpose

To present a 22-month-old girl with a complete retinal detachment who was found to have systemic exam findings consistent with neurofibromatosis type 1 during the course of multi-specialty exam under anesthesia.

Observations

During examination under anesthesia, ophthalmic exam findings demonstrated retinal detachment with cyst formation, as well as peripheral non-perfusion of the retina in the left eye. Non-ophthalmic findings discovered on difficulty with intubation included a laryngeal plexiform neurofibroma and café-au-lait spots.

Conclusions

Pediatric retinal detachments are uncommon compared to those in adults. Pediatric patients with neurofibromatosis type 1 can present with vision loss as the presenting symptom. Systemic signs and symptoms should be carefully screen and monitored.

Features of CT and EUS in mesenteric plexiform neurofibroma with Neurofibromatosis type I: A case report

Plexiform neurofibroma(PNF) is a rare benign tumor of the peripheral nerve, belonging to a subtype of neurofibroma. PNF is common in the head, neck and trunk. It is uncommonly observed in the mesentery. We report a case of mesenteric PNF in a 64-year-old man history of neurofibromatosis type I(NF1), which caused abdomen pain. In addition, the computer tomography(CT) and endoscopic ultrasonography(EUS) manifestations of mesenteric PNF were analyzed. The imaging appearance of a mesenteric plexiform neurofibroma is that many low-density (CT) /mixed echo (EUS) soft tissue masses surrounding the superior mesenteric artery, but not surrounding the superior mesenteric vein. Our case adds to the limited literature regarding NF1 presenting with mesenteric PNF. The computer tomography and endoscopic ultrasonography may facilitate confirma diagnosis of mesenteric PNF.

Imaging diagnosis of plexiform neurofibroma- unravelling the confounding features: A report of two cases

Peripheral nerve sheath tumors such as neurofibroma, comprise 5% of all benign soft tissue tumors and usually occur due to an underlying neurofibromatosis. A plexiform neurofibroma, which is a tumor occurring exclusively in neurofibromatosis1, is a rare entity and is an uncommon variant of neurofibroma. We report the clinical and imaging features of plexiform neurofibroma in two young male patients, in whom the imaging diagnosis was confirmed after biopsy. The report not only aims to highlight the characteristic imaging features of plexiform neurofibroma but we also emphasize the ultrasound appearances which are significantly characteristic and can effectively lead to the correct diagnosis at the preliminary stage of investigation. The tumors which originate from nerve sheath, are large, lobulated masses and demonstrate typical imaging features of simultaneous involvement of subcutaneous and cutaneous tissues along with infiltrative invasion of deeper structures. The tumors characteristically display fat and fluid contents and a “target sign’ on evaluation by ultrasound, CT and MRI. Imaging plays an important role in confirming the diagnosis, delineating involved structures, excluding simulating conditions and forewarning a possible malignant transformation.

Trametinib for orbital plexiform neurofibromas in young children with neurofibromatosis type 1

INTRODUCTION

Plexiform neurofibromas (PNF) in neurofibromatosis type 1 (NF1) are usually diagnosed in childhood and can grow rapidly during this period. In 10% of patients, PNF involve the orbital-periorbital area and may cause visual problems including glaucoma, visual loss from amblyopia (deprivational, strabismic, or refractive), optic nerve compression, or keratopathy. Ptosis, proptosis, and facial disfigurement lead to social problems and decreased self-esteem. Complete surgical removal involves significant risks and mutilation, and regrowth after debulking is not uncommon. Inhibitors of the RAS/MAPK pathway have recently been investigated for their activity in PNF. We administered the oral MEK inhibitor trametinib to five young children with NF1 and PNF of the orbital area, with visual compromise and progressive tumor growth; and followed them clinically and by volumetric MRI.

METHODS

Treatment was initiated at a mean age of 26.8 months (SD ± 12.8) and continued for a median 28 months (range 16-51). Doses were 0.025 mg/kg/day for children aged > 6 years and 0.032 mg/kg/day for those aged < 6 years.

RESULTS

Volumetric MRI measurements showed a reduction of 2.9-33% at 1 year after treatment initiation, with maximal reductions of 44% and 49% in two patients, at 44 and 36 months, respectively. No change in visual function was recorded during treatment. One child reported decreased orbital pain after 2 weeks; and another, with involvement of the masseters, had increased ability to chew food. Toxicities were mostly to skin and nails, grades 1-2.

CONCLUSIONS

Trametinib can decrease tumor size in some young children with orbital PNF and may prevent progressive disfigurement.

Clinical features and disease severity in patients with mosaic neurofibromatosis type 1: a single-center study and literature review

Background

The mosaic form of neurofibromatosis type 1 (NF1) is called mosaic NF1 (MNF1). No specific MNF1 follow-up guidelines exist. It is debatable if patients with MNF1 should be clinically examined and undergo follow-up in accordance with the standard NF1 guidelines, as MNF1 patients more often may develop more benign phenotypes and thereby less disease-associated complications including cognitive impairment. We discussed the need for a specific MNF1 follow-up guideline with focus on frequency of plexiform neurofibromas and NF1-associated complications.

Method

A systematic retrospective data collection in a MNF1 cohort from one of two Danish national centers of NF1 Expertise was completed. Data collected included demographics, clinical features including NF1 diagnostic criteria and NF1-associated complications. Recent literature in the field was reviewed.

Results

We identified 17 patients with MNF1 with a median age of 37 years [4; 66]. Eleven (65%) were females. Five patients (30%) had a plexiform neurofibroma. The median age at detection of plexiform neurofibroma was 30 years [14; 60]. Nine (53%) had at least one NF1-related complication; scoliosis, hypertension, ADHD, learning disability, language delay, autism and delay in gross and fine motor function development. We reviewed nine articles. In total, 126 cases were described within three case-series. Nineteen (15%) had a plexiform neurofibroma and in total, 23 NF1-associated complications were reported including language delay, learning disability and skeletal abnormalities. Furthermore, from the literature it was evident that the diagnosing of MNF1 varies among physicians and across countries.

Conclusion

Patients with MNF1 present with plexiform neurofibromas and other NF1-related complications with a frequency requiring that follow-up of MNF1 patients should be in accordance with the standard NF1 guideline in both childhood and adulthood. Physicians should be aware of cognitive impairment as a complication to MNF1. To develop a specific MNF1 follow-up guideline, there is a need for an international consensus on the diagnostic criteria for MNF1 and a follow-up study conducted in a larger MNF1 cohort.

Neurofibromatosis in the Era of Precision Medicine: Development of MEK Inhibitors and Recent Successes with Selumetinib

PURPOSE OF REVIEW

Patients with neurofibromatosis type 1 (NF1) are at increased risk for benign and malignant neoplasms. Recently, targeted therapy with the MEK inhibitor class has helped address these needs. We highlight recent successes with selumetinib while acknowledging ongoing challenges for NF1 patients and future directions.

RECENT FINDINGS

MEK inhibitors have demonstrated efficacy for NF1-related conditions, including plexiform neurofibromas and low-grade gliomas, two common causes of NF1-related morbidity. Active investigations for NF1-related neoplasms have benefited from advanced understanding of the genomic and cell signaling alterations in these conditions and development of sound preclinical animal models. Selumetinib has become the first FDA-approved targeted therapy for NF1 following its demonstrated efficacy for inoperable plexiform neurofibroma. Investigations of combination therapy and the development of a representative NF1 swine model hold promise for translating therapies for other NF1-associated pathology.

Increased nuclear translation of YAP might act as a potential therapeutic target for NF1-related plexiform neurofibroma

Plexiform neurofibroma (pNF) in the head and neck is a characteristic feature in patients with neurofibromatosis type 1 (NF1) and is associated with significant disfigurement and psychological distress. Yes-associated protein (YAP), the key molecule involved in the Hippo pathway, is a vital transductor that regulates the proliferation and remyelinating of Schwann cells. The functional status of YAP and its feasibility as a potential target are still unknown in pNF. A total of 17 pNF tumor tissue specimens from the head and neck were collected at the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine. Histologically, diagnosis of the Schwann cell region in pNF was achieved with hematoxylin-eosin staining, positive reactions for S100, SOX10, ERK and p-ERK, and low identification of Ki67 and SMA. Compared with normal nerve tissue, obviously increased nuclear YAP was detected in the Schwann cell region of pNF, with a mean nuclear staining rate of 67.11%. Based on the shNF1 Schwann cell model (the RSC96 cell line), with upregulated expression of RAS, ERK and p-ERK, p-YAP (Ser127) and p-YAP (Ser397) were significantly decreased and total YAP and nuclear YAP were increased. According to a confocal assay, the interference of shNF1 substantially promoted YAP nuclear translocation. Compared with control Schwann cells, the YAP inhibitor CA3 might have a more sensitive effect (IC₅₀: NC=0.96±0.04, shNF1=0.71±0.02, P<0.05) on the shNF1 Schwann cell model than the classic MEK1/2 inhibitor selumetinib (IC₅₀: NC=14.36±0.95, shNF1=24.83±0.98, P>0.05). For in vivo inhibition, the CA3 group and the selumetinib group displayed a similar inhibition effect with no significant difference. Increased nuclear translation and the functional state of YAP implies that the YAP-Hippo pathway might play an important role in the formation and remyelination of pNF. Compared with selumetinib, the YAP inhibitor can exhibit a similar but more sensitive effect on NF1^-/- Schwann cells. These observations imply that YAP as a novel or adjuvant therapy target in the treatment of pNF.

Modeling tumors of the peripheral nervous system associated with Neurofibromatosis type 1: Reprogramming plexiform neurofibroma cells

Plexiform neurofibromas (pNFs) are benign tumors of the peripheral nervous system (PNS) that can progress towards a deadly soft tissue sarcoma termed malignant peripheral nerve sheath tumor (MPNST). pNFs appear during development in the context of the genetic disease Neurofibromatosis type 1 (NF1) due to the complete loss of the NF1 tumor suppressor gene in a cell of the neural crest (NC) - Schwann cell (SC) axis of differentiation. NF1(-/-) cells from pNFs can be reprogrammed into induced pluripotent stem cells (iPSCs) that exhibit an increased proliferation rate and maintain full iPSC properties. Efficient protocols for iPSC differentiation towards NC and SC exist and thus NC cells can be efficiently obtained from NF1(-/-) iPSCs and further differentiated towards SCs. In this review, we will focus on the iPSC modeling of pNFs, including the reprogramming of primary pNF-derived cells, the properties of pNF-derived iPSCs, the capacity to differentiate towards the NC-SC lineage, and how well iPSC-derived NF1(-/-) SC spheroids recapitulate pNF-derived primary SCs. The potential uses of NF1(-/-) iPSCs in pNF modeling and a future outlook are discussed.

Esthetic subunit approach in massive facial plexiform neurofibroma: a case report

Plexiform neurofibroma is a presentation of neurofibromatosis type 1 (NF1) which can cause great facial deformities. Treatment rarely has a healing effect, so the surgical approach is aimed at improving esthetics and function. It requires a cross-disciplinary approach and typically needs multi-stage surgery. This is the case of a 16-year-old male patient with NF1 presenting with left periorbital and malar facial plexiform neurofibroma with slow-growth intraconal and extraconal invasion. He presented at the plastic surgery consultation for facial soft tissue deformity correction. Removal was performed using an esthetic subunit approach, with canthopexy and orbital cavity reconstruction, resulting in facial region symmetrization. This allowed for remarkable esthetic and functional improvement, facilitating ocular prosthesis adaptation. The subsequent use of selumetinib allowed the lesion to be stabilized.

Current status of MEK inhibitors in the treatment of plexiform neurofibromas

BACKGROUND

Neurofibromatosis type 1 (NF1)-related plexiform neurofibromas (pNF) can be debilitating and until recently, surgery was the only potentially effective therapy for these tumors.

METHODS

We review critical steps in the path towards the FDA approval of the first medical therapy for NF1 pNF and the current status of MEK inhbitor therapy.

RESULTS

Sustained efforts by the NF community have resulted in a detailed understanding of the natural history and biology of NF1-related peripheral nerve sheath tumors. This work provided the basis for the development of meaningful clinical trials targeting pNF. Inhibition of the RAS/MAPK signaling pathway with MEK inhibitors identified the first medical therapy which resulted in shrinkage in the majority of children with NF1 and large inoperable pNF. Based on this finding and subsequent demonstration of clinical benefit, the MEK inhibitor selumetinib recently received approval by the United States Food and Drug Administration (FDA) for children with symptomatic pNF.

CONCLUSIONS

Sustained efforts and collaborations have resulted in identification of MEK inhibitors as effective therapy for NF1 pNF. Future work work will be directed at prevention of pNF morbidity and deepening the reponse in symptomatic pNF.

A rare case of plexiform neurofibroma of the liver in a patient without neurofibromatosis type 1

Plexiform neurofibroma is mainly associated with neurofibromatosis type 1 and is seldom observed in the liver. Its occurrence in the liver without neurofibromatosis type 1 is even rarer. We report an extremely rare case of plexiform neurofibroma of the liver diagnosed by laparoscopic biopsy in a patient without neurofibromatosis type 1. The patient was a 35-year-old man who had neither clinical signs nor any family history of neurofibromatosis type 1. Abdominal ultrasonography, as part of a health screening, had detected a hepatic tumor. Subsequent contrast ultrasonography, computed tomography, and magnetic resonance imaging showed the tumor extending from the retroperitoneal space around the aorta to the hepatic hilum and distal portal branches in the right hepatic lobe, gallbladder, and left hepatic lobe. ¹⁸F-fluorodeoxyglucose positron emission tomography showed no abnormal accumulation. Histopathological examination of the tumor obtained laparoscopically led to a diagnosis of plexiform neurofibroma. Because the patient was asymptomatic with no features of malignancy, he was only monitored and managed. At follow-up 10 years later, computed tomography showed a decrease in tumor size. It is important to recognize that, while rare, plexiform neurofibroma can occur without neurofibromatosis type 1. We recommend follow-up instead of unreasonable surgery in such cases.

The Use of MEK Inhibitors in Neurofibromatosis Type 1-Associated Tumors and Management of Toxicities

Early-phase clinical trials using oral inhibitors of MEK, the mitogen-activated protein kinase kinase, have demonstrated benefit for patients with neurofibromatosis type 1 (NF1)-associated tumors, particularly progressive low-grade gliomas and plexiform neurofibromas. Given this potential of MEK inhibition as an effective medical therapy, the use of targeted agents in the NF1 population is likely to increase substantially. For clinicians with limited experience prescribing MEK inhibitors, concern about managing these treatments may be a barrier to use. In this manuscript, the Clinical Care Advisory Board of the Children's Tumor Foundation reviews the published experience with MEK inhibitors in NF1 and outlines recommendations for side-effect management, as well as monitoring guidelines. These recommendations can serve as a beginning framework for NF providers seeking to provide the most effective treatments for their patients. IMPLICATIONS FOR PRACTICE: Neurofibromatosis type 1 (NF1) clinical care is on the cusp of a transformative shift. With the success of recent clinical trials using MEK inhibitors, an increasing number of NF1 patients are being treated with MEK inhibitors for both plexiform neurofibromas and low-grade gliomas. The use of MEK inhibitors is likely to increase substantially in NF1. Given these changes, the Clinical Care Advisory Board of the Children's Tumor Foundation has identified a need within the NF1 clinical community for guidance for the safe and effective use of MEK inhibitors for NF1-related tumors. This article provides a review of the published experience of MEK inhibitors in NF1 and provides recommendations for monitoring and management of side effects.

Cardiac overload resolved by resection of a large plexiform neurofibroma on both the buttocks and upper posterior thighs in a patient with neurofibromatosis type I: a case report

Background

A large plexiform neurofibroma in patients with neurofibromatosis type I can be life threatening due to possible massive bleeding within the lesion. Although the literature includes many reports that describe the plexiform neurofibroma size and weight or strategies for their surgical treatment, few have discussed their possible physical or mental benefits, such as reducing cardiac stress. In addition, resection of these large tumors can result in impaired wound healing, partly due to massive blood loss during surgery.

Case presentation

A 24-year-old man was diagnosed with neurofibromatosis type I and burdened with a large plexiform neurofibroma on the buttocks and upper posterior thighs. The patient was 159 cm in height and 70.0 kg in weight at the first visit. Cardiac overload was indicated by an echocardiography before surgery. His cardiac output was 5.2 L/min with mild tricuspid regurgitation. After embolism of the arteries feeding the tumor, the patient underwent surgery to remove the neurofibroma, followed by skin grafting. Follow-up echocardiography, performed 6 months after the final surgery, indicated a decreased cardiac output (3.6 L/min) with improvement of tricuspid regurgitation. Because the blood loss during the first surgery was over 3.8 L, malnutrition with albuminemia was induced and half of the skin graft did not attach. Nutritional support to improve the albuminemia produced better results following a second surgery to repair the skin wound.

Conclusion

Cardiac overload may be latent in patients with neurofibromatosis type I with large plexiform neurofibromas. As in pregnancy, the body may compensate for this burden. In these patients, one stage total excision may improve quality of life and reduce cardiac overload. In addition, nutritional support is likely needed following a major surgery that results in either an extensive skin wound or excessive blood loss during treatment.

[Management of cervico-cephalic plexiform neurofibromas: About 35 cases]

OBJECT

Plexiform neurofibroma is a characteristic lesion of Von Recklinghausen's disease. Conservative surgery is the most widely adopted treatment. However, it is very challenging because of its hemorrhagic nature and the infiltrative aspect of the lesions. The aim of this study was to evaluate our management.

PATIENTS AND METHOD

A retrospective study over 16 years was realized and during this period 35 patients with neurofibroma with cervico-facial location were included.

RESULTS

There were 18 men and 17 women with an average age of 23 years (3-50 years). The familial form was found in 9% of patients. Aesthetic discomfort was noted in all patients and functional impairment only occurred in 10% of patients. The NFP was localized at the hemiface in 11 cases, periorbital in 6 cases, naso-labial in 5 cases, scalp in 4 cases, jugal in 4 cases and cervico-chin in 5 cases. Size of the lesions averaged 11.6cm (4-45cm). Eighteen patients (51.4%) were operated including 10 by modeling resection, 05 cervico-facial lifting and 3 complete resections. Complication rate was 28% dominated by disunion wound. The average number of procedures was 1.6 (1 to 5). After 3 years average follow-up, aesthetic et functional results was assessed as good over 75 per cent of patients.

CONCLUSION

Cervico-facial plexiform neurofibromas is challenging. Conservative surgery should be the gold standard and long time follow-up is recommended.

Lumbosacral plexiform neurofibroma: a rare case in an adult without neurofibromatosis type I

Plexiform neurofibromas are an uncommon variant of neurofibromas that are described as being essentially pathognomonic of neurofibromatosis type 1 (NF1). Plexiform neurofibromas in the absence of NF1 are extremely rare. We present the case of a 38-year-old woman with a large multilobulated lumbosacral mass extending into the pelvis and proximal thigh. Histopathology of a CT-guided biopsy of the mass revealed it to be a neurofibroma. The imaging findings were consistent with a plexiform subtype. Further imaging and clinical workup showed that the patient had no other identifiable neurofibromas and did not meet criteria for the diagnosis of NF1.

A phase 2 study of trametinib for patients with pediatric glioma or plexiform neurofibroma with refractory tumor and activation of the MAPK/ERK pathway: TRAM-01

BACKGROUND

Pediatric low-grade gliomas (PLGG) are the most frequent brain tumors in children. Up to 50% will be refractory to conventional chemotherapy. It is now known that the majority of PLGG have activation of the MAPK/ERK pathway. The same pathway is also activated in plexiform neurofibromas (PNs) which are low-grade tumors involving peripheral nerves in patients with neurofibromatosis type 1 (NF1). These lesions are known to be refractory to chemotherapy. Specific MEK inhibitors such as trametinib are now available and have been approved for other cancers harboring mutations in the MAPK/ERK pathway such as melanoma. We have observed significant responses to trametinib in patients with refractory PLGG in our institutions and results from the phase I study are promising. The treatment appears not only efficacious but is also usually well tolerated. We hypothesize that we will observe responses in the majority of refractory PLGG and PN treated with trametinib in this phase 2 study.

METHODS

The primary objective is to determine the objective response rate of trametinib as a single agent for treatment of progressing/refractory tumors with MAPK/ERK pathway activation. The TRAM-01 study is a phase II multicentric open-label basket trial including four groups. Group 1 includes NF1 patients with progressing/refractory glioma. Group 2 includes NF1 patients with plexiform neurofibroma. Group 3 includes patients with progressing/refractory glioma with KIAA1549-BRAF fusion. Group 4 includes other patients with progressing/refractory glioma with activation of the MAPK/ERK pathway. Eligible patients for a given study group will receive daily oral trametinib at full dose for a total of 18 cycles of 28 days. A total of 150 patients will be enrolled in seven Canadian centers. Secondary objectives include the assessment of progression-free survival, overall survival, safety and tolerability of trametinib, serum levels of trametinib and evaluation of quality of life during treatment.

DISCUSSION

Trametinib will allow us to target directly and specifically the MAPK/ERK pathway. We expect to observe a significant response in most patients. Following our study, trametinib could be integrated into standard treatment of PLGG and PN.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03363217 December 6, 2017.

The Diagnosis and Management of Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1), NF2, and schwannomatosis are related, but distinct, tumor suppressor syndromes characterized by a predilection for tumors in the central and peripheral nervous systems. NF1 is one of the most common autosomal dominant conditions of the nervous system. NF1 has a high degree of variability in clinical presentation, which may include multiple neoplasms as well as cutaneous, vascular, bony, and cognitive features. Some of these manifestations overlap with other genetic conditions. Accurate diagnosis of NF1 is important for individualizing clinical care and genetic counseling. This article summarizes the clinical features, diagnostic work-up, and management of NF1.

Fluorescein-guided resection of plexiform neurofibromas: how I do it

BACKGROUND

Plexiform neurofibromas (PN) can determine pain, nerve function impairment, and, when extremely large, also deformity. Surgical is often partial, with possible recurrence, and the risk of malignant transformation.

METHOD

We describe the surgical strategy in a case of huge multiple plexiform neurofibromas of the left arm. We attempted to achieve a safe resection under the intraoperative guidance of fluorescein, with a dedicated microscope filter (YELLOW560). This technique can be also applied to other locations.

CONCLUSION

Fluorescein-guided surgery, coupled with intraoperative neurophysiological monitoring, increases the safe resection rate, considering the risks of neurological deficits and the possible malignant transformation.

Giant Plexiform Neurofibroma of the Perineum and Pelvic Cavity Manifesting as Segmental Neurofibromatosis

Segmental neurofibromatosis (SN) is rare form of neurofibromatosis characterized that cutaneous or neural changes are limited to one region of the body. SN present neurofibroma and less frequently, café au lait macules (CALMs) on usually unilateral or rarely bilateral of the body region. SN seems to have fewer systemic complications than neurofibromatosis type I or II, except patients with plexiform neurofibromas (PNFs). PNFs are rare benign peripheral nerve sheath tumors which arise from single or multiple nerves. PNFs can easily become aggressive growth particularly during puberty or pregnancy and leading to disfigurement and functional impairment. Also, PNFs can transform to malignant peripheral nerve sheath tumor, higher rate than classic neurofibroma. So, it is important to decide appropriate treatment modalities and time to intervention.

Ischiorectal fossa: benign and malignant neoplasms of this "ignored" radiological anatomical space

PURPOSE

To review the pertinent anatomy and the imaging features of common and uncommon benign and malignant neoplasms and masses of the ischiorectal fossa.

RESULTS

The ischiorectal or ischioanal fossa is the largest space in the anorectal region. The benign neoplasms that develop in the ischiorectal originate from the different components that forms the fossa including vascular tumors such as aggressive angiomyxoma or hemangioma; neural tumors as plexiform neurofibroma or schwannoma; fat tumors as lipoma; skin/skin appendages tumors as hidradenoma papilliferum; smooth or skeletal muscle tumors as solitary fibrous tumor. The malignant neoplasms that develop in the ischiorectal fossa also originate from different components that forms the fossa including vascular tumors such as angiosarcoma, neural tumors as malignant granular cell tumor and malignant peripheral nerve sheath tumor; fat tumors as liposarcoma; smooth or skeletal muscle tumors as leiomyosarcoma, rhabdomyosarcoma, malignant PEComa, or undifferentiated pleomorphic sarcoma. Additionally, the ischiorectal fossa can also harbor secondary hematogenous metastases and be affected by direct invasion from neoplasms of adjacent pelvic organs and structures. Furthermore, other miscellaneous masses can occur in the ischiorectal fossa including congenital and developmental lesions, and inflammatory and infectious processes.

CONCLUSION

Knowledge of the anatomy, and the spectrum of imaging findings of common and uncommon benign and malignant neoplasms of the ischiorectal fossa is crucial for the radiologists during interpretation of images allowing them to make contributions to the diagnosis and better patient management.

Giant Pelvic Neurofibroma in Patient with Plexiform Sciatic Neurofibroma and Neurofibromatosis Type 1

BACKGROUND

Neurofibromatosis is a genetic disease with an autosomal dominant type of inheritance. It is a multisystem disease in which, besides skin manifestations, there is a possibility for the involvement of other organs and systems, and an atypical variant of neurofibromatosis type 1 can also be observed- the so-called plexiform neurofibroma. In patients with this inherited disease, mortality is higher due to the existing risk for malignant transformation and development of malignant peripheral nerve sheath tumours (MPNSTs) or neurofibrosarcoma.

CASE REPORT

We present a 25-year-old woman with neurofibromatosis type 1 and a family history of the disease-father and grandmother with NF-1, with fatal outcome in the grandmother as a result of malignant transformation to neurofibrosarcoma. The patient has clinical data for multiple cafés- au- lait spots on the skin of the trunk, upper and lower limbs, and plexiform tumour formation in the seating area. From the performed imaging diagnostic there are available MRT data for 1) giant pelvic neurofibroma, 2) plexiform giant neurofibroma in the subcutaneous fat on the right thigh and gluteal fat tissue to the right, passing through the midline in the area of the external genitalia, leading to deformation of the front wall of the sacrum with bilateral meningoceles and 3) diffuse involvement of the bladder wall from the process in the area of the trigonum vesicae felleae/the two urethral ostium, as well as 4) the presence of neurofibromas in the course of the iliac vessels on the right. Surgical removal of the oval pelvic formation, identified as neurofibroma was planned, as well as the initiation of systemic therapy with Sirolimus for the plexiform sciatic formation, infiltrating the bladder.

CONCLUSION

Neurofibromatosis type-1 is a problematic disease due to the parallel systemic involvement of different organs and systems, which can be both limited and diffuse. Limited tumour lesions in the form of neurofibromas with diverse localisation (as in the patient we describe) could be surgically removed without difficulty. On the other hand, the diffuse involvement of internal organs within a giant, network-3spreading plexiform neurofibromas (as in the described patient) makes interdisciplinary interventions impossible, and therefore therapeutic alternatives should be considered.

Clinical, radiological features and surgical strategies for 23 NF1 patients with intraorbital meningoencephalocele

Intraorbital meningoencephalocele is a rare manifestation of neurofibromatosis type 1 (NF1) caused by secondary changes in sphenoid dysplasia, and it seriously affects patients' vision and facial appearance. We retrospectively analyzed the clinical data of 23 patients with NF1 and intraorbital meningoencephalocele, summarized the surgical strategies employed, and evaluated their clinical efficacy in order to better understand its management in clinical practice, establish a reasonable surgical strategy, and assess prognosis. Before surgery, 22 patients had unilateral pulsatile exophthalmos, 18 patients had significant visual impairment, and 13 patients had ptosis associated with an orbital plexiform neurofibroma (PNF). All 23 patients underwent microsurgical craniotomy with skull base reconstruction using a soft titanium mesh. One month after surgery, the degree of exophthalmos in the 22 (95.65%) patients was significantly reduced compared with before surgery (P < 0.001), and ocular pulsation had subsided. The visual acuity did not decrease significantly (P = 0.298) compared with before surgery. Eleven (47.83%) patients received phase-II eyelid PNF resection and/or oculoplastic surgery, and the degree of ptosis was significantly reduced (P < 0.001). There was no recurrence of pulsatile exophthalmos, displacement of titanium mesh, decreased visual acuity, or increased degree of ptosis noted during follow-up. The best strategy is to reconstruct the skull base under microscopy to relieve pulsating exophthalmos and preserve existing visual function. In cases of ptosis caused by an eyelid PNF, surgical resection should be performed as soon as possible to remove the tumor, and/or oculoplastic surgery should be performed to improve the cosmetic outcome.

Lifespan Development: Symptoms Experienced by Individuals with Neurofibromatosis Type 1 Associated Plexiform Neurofibromas from Childhood into Adulthood

This secondary data analysis qualitatively identified salient concerns reported by individuals with Neurofibromatosis Type 1 (NF1)-associated plexiform neurofibromas (pNFs) at different stages of development. Past literature has focused on overall symptomatology, but has not examined nuances in how these symptoms are experienced across developmental phases. Therefore, we aimed to identify commonalities and differences in symptom experiences across age groups to better assist individuals to adjust to symptoms across the lifespan. Thirty-one children, adolescents, and adults (age ≥ 5 years old) and 15 parents participated in semi-structured interviews. Analyses focused on the following symptom categories: pain, social functioning, physical function impact, and stigma. Aspects of pain endorsed by all age groups included localized brief pain on contact with pNF and abnormal sensations; however, only adolescents and adults reported chronic pain and change in pain over time. Social functioning themes of limited activity participation, role limitations, and relationship impact were endorsed by all age groups, but differences emerged across age groups in the types of activity and role limitations, the type of relationship impact, and family planning concerns. All age groups described difficulty with mobility, but only parents reported problems with coordination and physical developmental milestones. While all age groups reported external stigma, internalized stigma was predominately endorsed by adults. While individuals in all age groups described pNF concerns related to pain, social function, physical function, and stigma, specific aspects of these symptoms differed across the developmental continuum. These findings can help assist individuals with pNF better transition to the next developmental phases.

Radiomic biomarkers informative of cancerous transformation in neurofibromatosis-1 plexiform tumors

BACKGROUND

This study explores whether objective, quantitative radiomic biomarkers derived from magnetic resonance (MR), positron emission tomography (PET), and computed tomography (CT) may be useful in reliably distinguishing malignant peripheral nerve sheath tumors (MPNST) from benign plexiform neurofibromas (PN).

METHODS

A registration and segmentation pipeline was established using a cohort of NF1 patients with histopathological diagnosis of PN or MPNST, and medical imaging of the PN including MR and PET-CT. The corrected MR datasets were registered to the corresponding PET-CT via landmark-based registration. PET standard-uptake value (SUV) thresholds were used to guide segmentation of volumes of interest: MPNST-associated PET-hot regions (SUV≥3.5) and PN-associated PET-elevated regions (2.0<SUV<3.5). Quantitative imaging features were extracted from the MR, PET, and CT data and compared for statistical differences. Intensity histogram features included (mean, media, maximum, variance, full width at half maximum, entropy, kurtosis, and skewness), while image texture was quantified using Law's texture energy measures, grey-level co-occurrence matrices, and neighborhood grey-tone difference matrices.

RESULTS

For each of the 20 NF1 subjects, a total of 320 features were extracted from the image data. Feature reduction and statistical testing identified 9 independent radiomic biomarkers from the MR data (4 intensity and 5 texture) and 4 PET (2 intensity and 2 texture) were different between the PET-hot versus PET-elevated volumes of interest.

CONCLUSIONS

Our data suggests imaging features can be used to distinguish malignancy in NF1-realted tumors, which could improve MPNST risk assessment and positively impact clinical management of NF1 patients.