Peripheral Nerve Tumors Research Articles

The impact of SARS-Covid-19 pandemic on peripheral nerve surgery – A single centre report

ObjectiveSARS-Cov-19 pandemic totally changed daily routine work in German hospitals. As hospital capacity was reduced, many surgeries were postponed or even cancelled. On March 25th 2020 the German Society of Neurosurgery (DGNC) published a statement in which urgent non-elective surgeries were defined for each neurosurgical domain, whereas elective interventions were deferred. The present work examines the impact of these Covid strategies focusing on patients with peripheral lesions who were conducted to our department during this period of time. MethodsAll patients who underwent any peripheral nerve surgery at our department from January 2018 until December 2022, were included. The complete range of surgeries including peripheral nerve lesions was examined encompassing compression syndromes, traumatic lesions of brachial plexus, traumatic lesions and tumors of single peripheral nerves. The numbers of surgical procedures were compared before, during and after pandemic. Pearson correlation coefficient was analysed. ResultsFrom 2018 to 2022 the total number of surgical procedures involving peripheral nerves included 2422 procedures. Compression syndromes made up the largest proportion (1433 operations, 59%), followed by peripheral nerve lesions (445 operations, 18%), peripheral nerve tumors (344 operations, 14%) and lesions of the brachial plexus (142 operations, 6%). The average was 40,5 interventions per month, the range was 7–63. Two declines in the number of peripheral nerve surgeries were noted during this period. The first was in April and May 2020 with an average drop of 65% and 41% respectively. In these months the average number of operations was 37. The second decrease was from October 2021 until January 2022, where number of surgeries was reduced by 16%, 36%, 83% and 18% with an average number of 50 operations. Both declines showed a significant and strong correlation with the lower number of compression syndrome treatments (r = 0.952, p < 0.001 and r = 0.968, p < 0.001), while no drop and no significant correlation was found in the treatment of traumatic peripheral nerve injuries (p = 0.769, r = 0.095 and p = 0.243, r = 0.366) and traumatic brachial plexus injuries (p = 0.787, r = 0.088 and p = 0.780, r = 0.09). A weak significant correlation was seen in the treatment numbers of peripheral nerve tumors (p = 0.017, r = 0.672 and p = 0.015, r = 0.67). ConclusionCovid-19 pandemic lead to a significant decrease in the number of nerve decompressions, since, according to the German Society of Neurosurgery, those were considered as elective surgeries.

Atypical presentation of an ancient retroperitoneal schwannoma mimicking a renal hydatid cyst: a case report and literature review

Schwannomas are benign neurogenic encapsulated peripheral nerve tumors of Schwann cells that rarely occur in the retroperitoneum. We present a case of a 22-year-old man who presented with right flank pain and was initially diagnosed as hydatid cyst based on the imaging and borderline results of anti-echinococcus (IgG). Albendazole was prescribed and taken for 4 months with no response and later underwent surgical excision of the mass. The diagnosis and morphology confirmed the nature of the schwannoma. Complete surgical excision remains the gold standard for the management of these tumors. The preoperative diagnosis is usually difficult; however, the definitive diagnosis is made upon histopathological examination.Author name: Please confirm if the author name are presented accurately and in the correct sequence (given name, middle name/initial, family name). Author 4 Given name: Asad Shahzad, Last name: Hasan.correct

Chapter 15 - Peripheral nerve tumors

The chapter is focused on the neoplastic peripheral nerve lesions, which primarily involve "cranial and paraspinal nerves," as outlined in the CNS volume (WHO_Classification_of_Tumours_Editorial_Board, 2021). These include classic peripheral nerve sheath tumors such as schwannoma, neurofibroma, intraneural perineurioma, and malignant peripheral nerve sheath tumors, with their variants as well as new and more precisely defined entities, including hybrid nerve sheath tumors and malignant melanotic nerve sheath tumor (previously melanotic schwannoma).

Clinical and pathological characteristics and expression of related molecules in patients with airway disseminated lung adenocarcinoma

Abstract Objective Lung adenocarcinoma exhibits diverse genetic and morphological backgrounds, in addition to considerable differences in clinical pathology and molecular biological characteristics. Among these, the phenomenon of spread through air space (STAS), a distinct mode of lung cancer infiltration, has rarely been reported. Therefore, this study aimed to explore the relationship between STAS tumor cells and the clinical and molecular characteristics of patients with lung adenocarcinoma, as well as their impact on prognosis. Methods This study included 147 patients who were diagnosed with lung adenocarcinoma at the Inner Mongolia Autonomous Region Cancer Institute between January 2014 and December 2017. Surgical resection specimens were retrospectively analyzed. Using univariate and multivariate Cox analyses, we assessed the association between STAS and the clinicopathological features and molecular characteristics of patients with lung adenocarcinoma. Furthermore, we investigated the effects on patient prognosis. In addition, we developed a column–line plot prediction model and performed internal validation. Results Patients with positive STAS had a significantly higher proportion of tumors with a diameter ≥2 cm, with infiltration around the pleura, blood vessels, and nerves, and a pathological stage &gt;IIB than in STAS-negative patients (P &lt; 0.05). Cox multivariate survival analysis revealed that clinical stage, STAS status, tumor size, and visceral pleural invasion were independent prognostic factors influencing the 5-year progression-free survival in patients with lung adenocarcinoma. The predictive values and P values from the Hosmer-Lemeshow test were 0.8 and 0.2, respectively, indicating no statistical difference. Receiver operating characteristic curve analysis demonstrated areas under the curve of 0.884 and 0.872 for the training and validation groups, respectively. The nomogram model exhibited the best fit with a value of 192.09. Conclusions Clinical stage, pleural invasion, vascular invasion, peripheral nerve invasion, tumor size, and necrosis are independent prognostic factors for patients with STAS-positive lung adenocarcinoma. The nomogram based on the clinical stage, pleural invasion, vascular invasion, peripheral nerve invasion, tumor size, and necrosis showed good accuracy, differentiation, and clinical practicality.

Expertise in surgical neuro-oncology. Results of a survey by the EANS neuro-oncology section

IntroductionTechnical advances and the increasing role of interdisciplinary decision-making may warrant formal definitions of expertise in surgical neuro-oncology. Research questionThe EANS Neuro-oncology Section felt that a survey detailing the European neurosurgical perspective on the concept of expertise in surgical neuro-oncology might be helpful. Material and methodsThe EANS Neuro-oncology Section panel developed an online survey asking questions regarding criteria for expertise in neuro-oncological surgery and sent it to all individual EANS members. ResultsOur questionnaire was completed by 251 respondents (consultants: 80.1%) from 42 countries. 67.7% would accept a lifetime caseload of >200 cases and 86.7% an annual caseload of >50 as evidence of neuro-oncological surgical expertise. A majority felt that surgeons who do not treat children (56.2%), do not have experience with spinal fusion (78.1%) or peripheral nerve tumors (71.7%) may still be considered experts. Majorities believed that expertise requires the use of skull-base approaches (85.8%), intraoperative monitoring (83.4%), awake craniotomies (77.3%), and neuro-endoscopy (75.5%) as well as continuing education of at least 1/year (100.0%), a research background (80.0%) and teaching activities (78.7%), and formal interdisciplinary collaborations (e.g., tumor board: 93.0%). Academic vs. non-academic affiliation, career position, years of neurosurgical experience, country of practice, and primary clinical interest had a minor influence on the respondents’ opinions. Discussion and conclusionOpinions among neurosurgeons regarding the characteristics and features of expertise in neuro-oncology vary surprisingly little. Large majorities favoring certain thresholds and qualitative criteria suggest a consensus definition might be possible.

Vagus Nerve Schwannoma

Schwannomas are peripheral nerve tumors that may impact cranial nerves. We present the case of a 21-year-old male with imaging findings consistent with vagal nerve schwannoma with an atypical symptomatic presentation. A review of the presentation, characteristic imaging findings, differential diagnosis, and treatment of vagal nerve schwannoma is provided.

Chapter 2 - The role of imaging in focal neuropathies

Electrodiagnostic testing (EDX) has been the diagnostic tool of choice in peripheral nerve disease for many years, but in recent years, peripheral nerve imaging has been used ever more frequently in daily clinical practice. Nerve ultrasound and magnetic resonance (MR) neurography are able to visualize nerve structures reliably. These techniques can aid in localizing nerve pathology and can reveal significant anatomical abnormalities underlying nerve pathology that may have been otherwise undetected by EDX. As such, nerve ultrasound and MR neurography can significantly improve diagnostic accuracy and can have a significant effect on treatment strategy. In this chapter, the basic principles and recent developments of these techniques will be discussed, as well as their potential application in several types of peripheral nerve disease, such as carpal tunnel syndrome (CTS), ulnar neuropathy at the elbow (UNE), radial neuropathy, brachial and lumbosacral plexopathy, neuralgic amyotrophy (NA), fibular, tibial, sciatic, femoral neuropathy, meralgia paresthetica, peripheral nerve trauma, tumors, and inflammatory neuropathies.

A RARE CASE OF SOLITARY NEUROFIBROMA OF NASAL TIP ANDCOLUMELLA OF NOSE

Neurofibroma is a most common benign nerve sheath tumor arising in peripheral nervous system. Neurofibroma are lesions arising from proliferation of axons, schwann cells, fibroblasts, perineural cells and endoneurium. Localized neurofibroma occur as solitary, superficial cutaneous tumour in individuals who do not have N e u r o fi b r o m a t o s i s 1 ( N F 1 ) . L o c a l i s e d Neurofibroma of external nose is rare lesion. Treatment of which is challenging in view of their position, cosmesis, reoccurrence rate. We report a case of neurofibroma involving unusual site of face, which are subcutaneous tissue of apex and columella of nose, and present a brief review of literature. KEYWORDS: Neurofibroma, Benign, Solitary, Peripheral Nerve Tumors, Nose, Neurofibromatosis, Columella

Development of a semi-automatic segmentation technique based on mean magnetic resonance imaging intensity thresholding for volumetric quantification of plexiform neurofibromas

Rationale and objectivesPlexiform neurofibromas (PNs) are peripheral nerve tumors that occur in 25–50 % of patients with neurofibromatosis type 1. PNs may have complex, diffused, and irregular shapes. The objective of this work was to develop a volumetric quantification method for PNs as clinical assessment is currently based on unidimensional measurement. Materials and methodsA semi-automatic segmentation technique based on mean magnetic resonance imaging (MRI) intensity thresholding (SSTMean) was developed and compared to a similar and previously published technique based on minimum image intensity thresholding (SSTMini). The performance (volume and computation time) of the two techniques was compared to manual tracings of 15 tumors of different locations, shapes, and sizes. Performance was also assessed using different MRI sequences. Reproducibility was assessed by inter-observer analysis. ResultsWhen compared to manual tracing, quantification performed with SSTMean was not significantly different (mean difference: 1.2 %), while volumes computed by SSTMini were significantly different (p < .0001, mean difference: 13.4 %). Volumes quantified by SSTMean were also significantly different than the ones assessed by SSTMini (p < .0001). Using SSTMean, volumes quantified with short TI inversion recovery, T1-, and T2-weighted imaging were not significantly different. Computation times used by SSTMean and SSTMini were significantly lower than for manual segmentation (p < .0001). The highest difference measured by two users was 8 cm3. ConclusionOur method showed accuracy compared to a current gold standard (manual tracing) and reproducibility between users. The refined segmentation threshold and the possibility to define multiple regions-of-interest to initiate segmentation may have contributed to its performance. The versatility and speed of our method may prove useful to better monitor volumetric changes in lesions of patients enrolled in clinical trials to assessing response to therapy.

Ultrasound imaging of median nerve neurolipomatosis: literature review and clinical case description

Neurolipomatosis is a rare benign tumor of peripheral nerves. The nerves of the upper extremities are more often involved, in most cases, the median nerves in the carpal canal. Children and young people suffer mainly. The article describes a case of fibrolipomatous hamarthroma of the median nerve in a 24-year-old patient, the ultrasound image is compared with the results of intraoperative observation. Despite the characteristic clinical and pathomorphological picture of this condition, the issues of diagnosis and differential diagnosis remain relevant. A special role is given to ultrasound as a non-invasive, widespread method of lifetime diagnosis of the condition of peripheral nerves. The median nerve, due to its superficial location, is available for visualization, and understanding the ultrasound semiotics of fibrolipomatous hamartoma will allow timely determination of it at the stage of initial clinical manifestations and avoid unnecessary and aggravating neurological deficits of examination methods such as biopsy.

EPCO-04. SPATIAL TRANSCRIPTOMIC ANALYSIS OF MALIGNANT PERIPHERAL NERVE SHEATH TUMORS REVEALS THERAPEUTICALLY TARGETABLE MOLECULAR SIGNATURES IN REGIONS UNDERGOING HISTOPATHOLOGIC TRANSFORMATION

Abstract Malignant peripheral nerve sheath tumors (MPNSTs) evolve from plexiform neurofibromas (pNF) in patients with neurofibromatosis type-1 (NF-1) yet the cellular and transcriptomic mechanisms underlying this transformation remain unclear. Here, we perform spatial gene expression profiling on fifteen MPNSTs to correlate histologic observations with transcriptomic programs and identify mechanisms underlying malignant transformation. METHODS: Fifteen MPNSTs, including tumors with a histopathologically defined transition zone between adjacent low-grade and high-grade areas (n=3), were retrospectively identified. Spatial transcriptomic profiling was performed using Visium followed by downstream processing with SpaceRanger, Seurat, Harmony, and monocle. RESULTS: 50,807 unique spatial transcriptomes were distributed across 17 unique clusters, of which 12 were enriched for tumor cells and 5 for non-tumor microenvironment cells based on histologic evaluation, unsupervised cell-type assignment, marker gene expression, and cell signature gene sets. Transcriptomic clusters in low-grade areas were enriched for genes regulating mononuclear cell migration and cell-cell adhesion, while high-grade regions were enriched for Ras/Raf/MEK/ERK target genes, anti-apoptotic programs, and extracellular matrix reorganization genes. Trajectory inference beginning in low grade regions revealed spatially organized molecular signatures of malignant transformation enriched for cell cycle progression within histopathologically homogeneous regions. Moreover, the intermediate transformation zone between low-grade neurofibromatous and high-grade MPNST histopathologic regions was marked by loss of cell differentiation genes and increased cell cycle progression. CONCLUSIONS: Spatial transcriptomic analysis elucidates the cellular and gene expression patterns underlying progression from pNF to MPNST. Distinct cell populations exist across low-grade, transformation zone, and high-grade regions in MPNSTs highlighted by alterations in Ras/Raf/MEK/ERK signaling, cell differentiation and cell cycle programs, shedding light on targets for combinatorial molecular therapy to decrease the risk of malignant transformation and serving as a biomarker of aggressive peripheral nerve tumors to complement conventional histopathology.

DDDR-03. DRUG REPURPOSING VIA ULTRA-HIGH THROUGHPUT 3D SPHEROIDS SCREENING FOR HUMAN SCHWANNOMA

Abstract Schwannoma is the most common benign peripheral nerve tumor occurring sporadically or as part of neurofibromatosis syndromes. While surgical resection can be used as the primary treatment option for Schwannoma, patients could face life-long repeated surgeries due to recurrence of syndromes that decreases the quality of life. Thus, non-invasive treatments for Schwannoma are highly demanded. To discover novel therapeutics for non-invasive Schwannoma treatment, in this project, we leveraged the benefits of drug repurposing high-throughput screening (HTS) of FDA-approved drugs using 3D spheroids derived from Schwannoma patient samples. Both 2D primary cells and 3D primary spheroids models were developed from an IRB-approved tumor bank of schwannoma patient samples. The 3D spheroids were validated to recapitulate the features of patient tumors. We then conducted an ultra-HTS(uHTS) in 1536-well format of 2036 FDA-approved drugs on the growth and viability of Schwannoma patient-derived 3D spheroids. Seven FDA-approved drugs were identified from the pilot screen to inhibit the growth of Schwannoma patient-derived 3D spheroids. These drugs offer potential to serve as pharmacotherapeutics for Schwannoma non-invasive treatment. Our results have demonstrated the capability of a drug repurposing strategy for Schwannoma using uHTS and a patient-derived tumor bank. We further demonstrated that patient-derived drug sensitivity signatures could be encoded from the screening data to enable clustering of patients, which accounts for heterogeneity in Schwannoma and avoids "one-size-fits-all" solutions in future non-invasive Schwannoma treatment studies.

Peripheral nerve tumors in adults and children: clinical and diagnostic characteristics

Aim. To describe clinical and instrumental characteristics of patients with primary solitary and multiple tumors of the peripheral nerves.Materials and methods. Data from 45 patients were analyzed. In accordance with the examination results, the patients were retrospectively divided into 2 groups: 1) with solitary tumors: schwannomas (n = 22), neurofibromas (n = 10), perineuriomas (n = 5), neurofibrosarcomas (n = 2); 2) with multiple tumors: schwannomatosis (n = 3) and neurofibromatosis (n = 3).Results. The study did not show differences in the severity of motor deficit and the results of neurophysiological exams between solitary and multiple tumors; however, differences between pathomorphological types were observed. The most benign disease course was observed in patients with schwannomas, including multiple schwannomas; severe motor deficit was observed in patients with neurofibrosarcomas and crossover neurofibromas. Pain component was characteristic of neurofibrosarcomas, neurofibromas and melanotic schwannoma; perineuriomas were characterized by painless progression.Conclusion. Compulsory scan along the nerve allows to find tumors in clinically intact areas and other nerves.

P02.14.B SPATIAL TRANSCRIPTOMIC ARCHITECTURE OF TUMOURS OF THE PERIPHERAL NERVOUS SYSTEM

Abstract BACKGROUND Studies into the genetics of peripheral nerve tumors have been focused on their association with known gene mutations and syndromes as well as on the tumor microenvironment of malignant peripheral nerve sheath tumors. Still, not many advances have been made into clarifying the structure and diverse pathophysiology of these tumors. Here we present spatially resolved transcriptomic profiling of benign and malignant entities and describe the topographical architecture of the neoplastic and microenvironmental diversity. MATERIAL AND METHODS We employed spatially resolved transcriptomics using the 10X Visium technology from paraffine embedded specimens. We included hybrid peripheral nerve sheath tumors (HPNSTs) plexiform neurofibromas and malignant peripheral nerve sheath tumors (MPNST). Computational analysis was employed by the SPATA2 toolbox. Transcriptomic niches were identified by graph-based spatial clustering. Correlation of histomorphological features and transcriptomic programs was performed by a co-expression network-based analysis. RESULTS We identified hub genes associated with neurofibroma and schwannoma histopathology across primary pathologies and discovered that neurofibroma regions of HPNSTs exhibited unique transcriptional programs marked by a significant higher local accumulation of bone-derived macrophages and lymphoid cells compared to primary neurofibromas. A novel marker, Apolipoprotein D (APOD), was found to accurately identify neurofibroma subregions in HPNSTs, which was confirmed by immunostaining in a control cohort. In MPNSTs, we observed a high grade of inter- and intrapatient heterogeneity driven by unique transcriptional niches and genetic variability. Subsequent pathway analysis revealed distinct oncogenic signaling driver across regional niches along with variance in immune infiltration. Our findings highlight the disbalance between histological annotation and actual tumor cell abundance in MPNSTs indicated by inferred copy number alterations. CONCLUSION Our integrated analysis pipeline revealed distinct transcriptional signatures and cellular interactions within benign PNSTs, including neurofibromas and hybrid peripheral nerve sheath tumors (HPNSTs) and sought to expose the tumor heterogeneity of MPNST and identify various cancer niches. Our study underscores the potential of spatially resolved transcriptomics as a powerful tool for advancing our understanding of PNST biology, and ultimately improving diagnosis, prognosis, and treatment strategies.

Surgery of Schwannoma in the upper limb – sensitivity and specificity of preoperative magnetic resonance imaging and relation between tumour size and symptoms

BackgroundBenign peripheral nerve tumours consist of different types, most commonly Schwannomas. Preoperative Magnetic Resonance Imaging (MRI) is commonly performed before surgery and Pathoanatomical Diagnosis (PAD) confirms the diagnosis. Our aims were to study the utility of MRI and the relation between tumour size and symptoms.MethodsRetrospectively, patients, surgically treated for benign nerve tumours between 2008 and 2019, were identified and preoperative MRI, with measurement of tumour size, PAD, symptoms, peroperative details, and symptomatic outcomes of surgery, were analysed.ResultsThe sensitivity and specificity to correctly identify Schwannomas with preoperative MRI were 85% and 50%, respectively, based on 30 Schwannomas and nine neurofibromas that were identified. Tumour size did not affect the presence of preoperative symptoms, but patients with sensory dysfunction at last follow-up had larger Schwannomas (p < 0.05). Symptoms as a palpable tumour, paraesthesia and pain improved by surgical excision (p < 0.001, p < 0.001 and p < 0.012, respectively), but sensory and motor dysfunction were common postoperatively. No malignant peripheral nerve sheath tumours (MPNST) were found. Using a surgical microscope, instead of only loop magnification, lowered the risk of perioperative nerve injuries (p < 0.05), but did not further diminish postoperative symptoms.ConclusionsEarly and accurate diagnosis of Schwannomas is valuable for adequate presurgical preparation and prompt surgical intervention. Preoperative examination with MRI has a high sensitivity, but low specificity; although recent advancement in MRI technology indicates improvement in diagnostic precision. Surgical excision is preferably performed early in conjunction with symptomatic debut to improve outcome.

7T for clinical imaging of benign peripheral nerve tumors: preliminary results.

MRI has become an essential diagnostic imaging modality for peripheral nerve pathology. Early MR imaging for peripheral nerve depended on inferred nerve involvement by visualizing downstream effects such as denervation muscular atrophy; improvements in MRI technology have made possible direct visualization of the nerves. In this paper, we share our early clinical experience with 7T for benign neurogenic tumors. Patients with benign neurogenic tumors and 7T MRI examinations available were reviewed. Cases of individual benign peripheral nerve tumors were included to demonstrate 7T MRI imaging characteristics. All exams were performed on a 7T MRI MAGNETOM Terra using a 28-channel receive, single-channel transmit knee coil. Five cases of four pathologies were selected from 38 patients to depict characteristic imaging features in different benign nerve tumors and lesions using 7T MRI. The primary advantage of 7T over 3T is an increase in signal-to-noise ratio which allows higher in plane resolution so that the smallest neural structures can be seen and characterized. This improvement in MR imaging provides the opportunity for more accurate diagnosis and surgical planning in selected cases. As this technology continues to evolve for clinical purposes, we anticipate increasing applications and improved patient care using 7T MRI for the diagnosis of peripheral nerve masses.

Benign nerve tumours in the upper limb: a registry-based study of symptoms and surgical outcome

Surgery for benign nerve tumours is performed for pathoanatomical diagnosis and symptomatic relief, but might cause residual problems. We aimed to assess patient-reported symptoms and disability before and after surgery at a national level. In total, 206 cases surgically treated for a benign peripheral nerve tumour 2010–2019 registered in the Swedish Quality Registry for Hand Surgery (HAKIR; response rates 22–34%) were analysed. Surgery reduced overall disability in the affected limb (QuickDASH 18/100 [IQR 5–36] preoperatively and 5/100 [IQR 0–22] 12 months postoperatively), improved ability to perform daily activities (HQ-8; 11/100 [IQR 0–50] preoperatively and 0/100 [IQR 0–20] 12 months postoperatively) and decreased three evaluated pain modalities: pain at rest (HQ-8; 20/100 [IQR 0–40] preoperatively and 0/100 [IQR 0–10] 12 months postoperatively), pain on motion without load (HQ-8; 20/100 [IQR 0–40] preoperatively and 0/100 [IQR 0–10] 12 months postoperatively), and pain on load (HQ-8; 24/100 [IQR 1–69] preoperatively and 1/100 [IQR 0–30] 12 months postoperatively). Cold sensitivity was a minor problem both before and after surgery (HQ-8; 0/100 [IQR 0–30] preoperatively and 1/100 [IQR 0–40] 12 months postoperatively). We conclude that surgery for benign peripheral nerve tumours provides good symptomatic relief with low risk for residual problems.

A Call for Discovery and Therapeutic Development for Cutaneous Neurofibromas

A Call for Discovery and Therapeutic Development for Cutaneous Neurofibromas

ID: 216029 Digital Nerve Block for a Painful Glomus Tumor of the Finger Tip: A Case Report

Neurofibromatosis type 1 (NF1) is an autosomal dominant, tumor predisposition disorder that commonly occurs approximately once every 2,500th live births. Mutations of the NF1 gene, especially of neural crest cells, result in functional changes to growth and cellular regulators of neurofibromin, leading to uncontrolled cellular proliferation and increased cancer risk (4). One particular concern for NF1 is the generation of peripheral nerve tumors, including glomus tumors. The classic triad of symptoms of glomus tumors include paroxysmal spontaneous pain, point tenderness, and cold hypersensitivity (10). Generally, the primary management of these tumors is complete resection while attempting to preserve residual neurological function. However, surgical involvement may result in life-changing complications, requiring significant specialization of hand and foot surgeries. Thus, more conservative management should be considered.

Neurofibromatosis Type 1-Associated Multiple Malignant Peripheral Nerve Sheet Tumors: A Case Report and Literature Review

Background: Neurofibromatosis type 1 (NF-1) is a genetic disorder characterized by café-au-lait macules, freckling, Lisch nodules, and neurofibromas. NF-1 patients have a special predisposition to tumorigenesis due to genetic mutations, affecting the tumor regulator systems. Malignant Peripheral Nerve Sheet Tumor (MPNST) is a highly aggressive soft tissue tumor that is usually associated with NF-1. Case presentation: A 32-year-old woman was presented complaining of weakness, severe fatigue, weight loss, peripheral paresthesia, progressive generalized myalgia, bone pain, and a mass sensation in her right thigh since three months ago. She was a known case of NF-1 since childhood. After clinical and radiological evaluation, multiple masses were detected in the retroperitoneal cavity adjacent to the left kidney, uterus, and right thigh. Finally, the patient was planned for surgical excision of two masses with subsequent chemotherapy. Both excised masses were confirmed as MPNSTs by histopathological examination. Conclusion: Regarding the predisposition of NF-1 patients to tumorigenesis and the high prevalence of peripheral nerve tumors among these patients, any masses changing their character should raise suspicion for malignancy. One of the serious malignant lesions is MPNST. The primary treatment plan for these malignant lesions is surgical excision with subsequent chemotherapy or radiotherapy based on individual characteristics.