Laser Interstitial Thermal Therapy as a Treatment Option for Malignant Peripheral Nerve Sheath Tumor Metastases to the Brain: A Case Report

We present the unique case of a 60-year-old female with neurofibromatosis type 1 (NF1) who underwent laser interstitial thermal therapy (LITT) for metastatic malignant peripheral nerve sheath tumor (MPNST) of the brain. She presented to the emergency room complaining of one week of dysarthria and facial droop. An MRI of the brain demonstrated a homogeneously enhancing left frontal mass; although rare, given her history of pulmonary MPNST, brain invasion was considered likely. No generally accepted guidelines for the treatment of MPNST with cerebral metastases exist; however, LITT was chosen due to tumor morphology and proximity to eloquent brain structures. She did not experience any new or worsening neurological deficits post-operatively. Post-ablation MRI showed white matter edema surrounding the lesion, which is consistent with previously reported cases. This case illustrates the use of LITT for cytoreduction for rare brain metastases located near eloquent brain structures.

Case report: Benign and malignant tumors in adult patients with neurofibromatosis type 1: a comprehensive case series from a large oncologic reference center

Purpose

Neurofibromatosis type 1 (NF1) is a complex, multisystem disorder that is characterized, among other features, by a higher risk of developing benign and malignant tumors. Despite NF1 being one of the most common autosomal dominant genetic disorders, data from adult individuals in several world regions remain elusive, including Hispanics.

Methods

The present is a retrospective cohort study conducted among adult patients with a confirmed diagnosis of NF1 who attended a single cancer-reference center, the Instituto Nacional de Cancerología in Mexico City from 2001 to 2021. Data were extracted from electronic health records and collected in an anonymous database by an NF1-expert physician in order to obtain demographic characteristics and detailed information regarding the development of tumors among this patient subgroup. All patients with malignant tumors or with benign tumors, which severely affected their quality of life, were included in this study.

Results

Patient records were reviewed from 2001 to 2021. A total of N = 29 patients met the criteria, with a higher proportion of female compared with male subjects [N = 22 (75.9%) vs. N = 7 (24.1%)]. Patients had a mean age at diagnosis of tumors of 32.2 years (SD = 11.2 years). In terms of malignant neoplasms, the most frequent malignant tumor presented by patients in this cohort was malignant peripheral nerve sheath tumors (N = 7, 24.1%), this was followed by breast cancer (n = 4, 13.8% among all patients, 18.2% among female patients). Other tumors also identified in this cohort included melanoma, gastrointestinal stromal tumors, and rectal cancer.

Conclusion

In Mexico, patients diagnosed with NF1 develop diverse tumors as adults. As described in other studies, the most frequent malignant tumor in this patient population is the malignant peripheral nerve sheath tumor. Further studies are required to increase the scarce information available for adult Hispanics with NF1.

A case report of giant malignant schwannoma of the sciatic nerve associated with neurofibromatosis-1: A CARE-compliant article

RATIONALE

Neurofibromatosis type 1 (NF1) is an autosomal dominant neurocutaneous syndrome that causes multiple central and peripheral nerve sheath tumors. People with NF1 have a 10% chance of developing malignant peripheral nerve sheath tumors (MPNSTs). Here we report a unique instance of a malignant schwannoma that has remained free of metastasis since its initial removal a decade ago. The malign schwannoma has been infrequently documented in the literature, and remarkably, no instances of such an extensive postoperative time without metastases have ever been described.

PATIENT CONCERNS

A 46-year-old male patient with NF had multiple neurofibromas in different parts of his body, underwent surgery about 10 years ago (2013), and was diagnosed histopathologically as MPNST.

DIAGNOSES

He was admitted to our institution with a recurrent mass in the posterior third of the proximal thigh and severe pain radiating to the left lower extremity, which presented as sciatic pain (2021). A magnetic resonance imaging and fluorodeoxyglucose-positron emission tomography examination revealed that the tumor was likely malignant.

INTERVENTIONS

Surgical excision was performed.

OUTCOME

A 10-year follow-up revealed no metastases or neurologic impairment.

LESSONS

When articles about benign schwannomas are placed in a separate category, little is written about NF-1-related malignant schwannomas of the sciatic nerve. MPNSTs are high-grade, aggressive sarcomas with a high risk of local recurrence (40%-65%) and metastasis to other body parts. Therefore, among the various benign peripheral nerve sheath tumors in NF-1 patients, the diagnosis of MPNST is crucial.Orthopedic surgeons should be aware that neurofibromas in NF-1 have a significant risk of developing MPNSTs. This study reports the successful treatment of a giant malignant sciatic nerve schwannoma with a long follow-up period without metastasis.

In Silico Identification of Therapeutic Targets and Novel Drug Candidates for Malignant Peripheral Nerve Sheath Tumors

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) are an aggressive form of sarcomas with a poor prognosis and limited treatment options. Therefore, new therapeutic targets are urgently needed to identify novel drugs.

METHODS

Based on the Gene Expression Omnibus database, an integrated analysis was performed to identify differentially expressed genes (DEGs) in MPNSTs compared to neurofibromas (NFs). Then functional enrichment analyses, protein-protein interaction (PPI) network construction, and hub gene selection were conducted. We explored DEG-guided repurposable drugs to treat MPNST based on the Library of Integrated Network-Based Cellular Signatures (LINCS) database. Furthermore, the binding affinity between predicted drug candidates and the MPNST-associated hub gene was calculated using molecular docking.

RESULTS

We identified 89 DEGs in common with all three MPNSTs datasets. In the PPI networks, twist family bHLH transcription factor 1 (Twist1) with higher node degrees was further evaluated as a therapeutic target. Cytochalasin-d, cabozantinib, everolimus, refametinib, and BGT-226 were extracted from the LINCS database, which showed lower normalized connectivity scores (-1.88, -1.81, -1.78, -1.76, and -1.72, respectively) and was considered as drug candidates. In addition, the results of molecular docking between the five drugs and Twist1 showed a binding affinity of -6.61, -7.03, -7.73, -3.94, and -7.07 kcal/mol, respectively.

CONCLUSIONS

Overall, our results describe the importance of Twist1 in MPNST pathogenesis. Everolimus was also found to be a potential therapeutic drug for MPNSTs.

The quest for effective immunotherapies against malignant peripheral nerve sheath tumors: Is there hope?

Immune-based therapies represent a new paradigm in the treatment of multiple cancers, where they have helped achieve durable and safe clinical responses in a growing subset of patients. While a wealth of information is available concerning the use of these agents in treating the more common malignancies, little has been reported about the use of immunotherapies against malignant peripheral nerve sheath tumors (MPNSTs), a rare form of soft tissue sarcoma that arises from the myelin sheaths that protect peripheral nerves. Surgical resection has been the mainstay of therapy in MPNSTs, but the recurrence rate is as high as 65%, and chemotherapy is generally ineffective. The immune contexture of MPNSTs, replete with macrophages and a varying degree of T cell infiltration, presents multiple opportunities to design meaningful therapeutic interventions. While preliminary results with macrophage-targeting strategies and oncolytic viruses are promising, identifying the subset of patients that respond to immune-based strategies will be a milestone. As part of our effort to help advance the use of immunotherapy for MPNSTs, here we describe recent insights regarding the immune contexture of MPNSTs, discuss emerging immune-based strategies, and provide a brief overview of potential biomarkers of response.

Low-Cost, High-Pressure-Synthesized Oxygen-Entrapping Materials to Improve Treatment of Solid Tumors

Tumor hypoxia drives resistance to many cancer therapies, including radiotherapy and chemotherapy. Methods that increase tumor oxygen pressures, such as hyperbaric oxygen therapy and microbubble infusion, are utilized to improve the responses to current standard-of-care therapies. However, key obstacles remain, in particular delivery of oxygen at the appropriate dose and with optimal pharmacokinetics. Toward overcoming these hurdles, gas-entrapping materials (GeMs) that are capable of tunable oxygen release are formulated. It is shown that injection or implantation of these materials into tumors can mitigate tumor hypoxia by delivering oxygen locally and that these GeMs enhance responsiveness to radiation and chemotherapy in multiple tumor types. This paper also demonstrates, by comparing an oxygen (O2 )-GeM to a sham GeM, that the former generates an antitumorigenic and immunogenic tumor microenvironment in malignant peripheral nerve sheath tumors. Collectively the results indicate that the use of O2 -GeMs is promising as an adjunctive strategy for the treatment of solid tumors.

Outcome of Patients With Malignant Peripheral Nerve Sheath Tumors Enrolled on Sarcoma Alliance for Research Through Collaboration (SARC) Phase II Trials

BACKGROUND

Evaluation of prior phase II trials for malignant peripheral nerve sheath tumors (MPNST) may help develop more suitable trial endpoints in future studies.

METHODS

We analyzed outcomes of patients with recurrent or unresectable/metastatic MPNST enrolled on prior Sarcoma Alliance for Research through Collaboration (SARC) phase II trials and estimated the progression-free survival (PFS). PFS from SARC006 (NCT00304083), the phase II trial of upfront chemotherapy in chemotherapy naïve patients, was analyzed separately. Impact of baseline enrollment characteristics on PFS was evaluated.

RESULTS

Sixty-four patients (29 male, 35 female, median age 39 years (range 15-81)) with MPNST were enrolled on 1 of 5 trials of single agent or combination therapy that were determined to be inactive. Patients had received a median of 1 (range 0-5) prior systemic therapy, and most had undergone prior surgery (77%) and radiation (61%). Seventy-three percent had metastatic disease at enrollment. Median PFS was 1.77 months (95% CI, 1.61-3.45), and the PFS rate at 4 months was 15%. Greater number of prior systemic therapies and worse performance status were associated with inferior PFS. There was no significant difference in PFS based on age at enrollment, treatment trial, response criteria, presence of metastatic disease, disease site at enrollment, and prior surgery or radiation. In comparison, on the SARC006 trial the PFS rate at 4 months was 94% in 40 patients.

CONCLUSION

These data provide a historical baseline PFS that may be used as a comparator in future clinical trials for patients with MPNST.

A worldwide bibliometric analysis of malignant peripheral nerve sheath tumors from 2000 to 2022

Background

Currently, malignant peripheral nerve sheath tumors (MPNST) are the subject of intense research interest. However, bibliometric studies have not been conducted in this field. The purpose of the study was to identify historical trends and presents a bibliometric analysis of the MPNST literature from 2000 to 2022.

Methods

For the bibliometric analysis, publications were retrieved from the Web of Science database based on the following search terms: [TI = (MPNST) OR TI= (malignant peripheral nerve sheath tumors) AND PY = (2000-2022)]. The following information was collected for each document: the publication trends and geographical distribution, important authors and collaboration, keyword distribution and evaluation, most popular journals, and most influential articles.

Results

We included 1400 documents for bibliometric analysis, covering five categories: 824 articles, 17 proceedings papers, 68 letters, 402 meeting abstracts, and 89 reviews. Corrections, editorials, book chapters, data papers, publications with expressed concerns, and retractions were excluded from our research.

Conclusion

Since 2000, the number of publications on MPNST has continuously increased. Among all countries that contributed to the MPNST research, the USA, Japan, and China were the three most productive countries. The journal Modern Pathology has the most publications on MPNST, while those in the Cancer Research journal were the most frequently cited. The University of Texas MD Anderson Cancer Center may be a good partner to collaborate with. Recent research trends in MPNST have focused on tumorigenesis, clinical management, and predictive biomarkers.

Case report: Brachial plexopathy caused by malignant peripheral nerve sheath tumor and review of the literature

Brachial plexopathy (BP) is easily misdiagnosed due to its complexity and varying clinical presentation. Malignant peripheral nerve sheath tumors (MPNST) can accumulate in the brachial plexus and share symptoms with BP, which may hinder the differential diagnosis between BP induced by radiation or metastases, and MPNST-derived BP, in patients with a history of breast cancer and radiation exposure. A 34-year-old Chinese female presented with MPNST. The tumor involved the brachial plexus. She had a history of breast cancer and radiotherapy. The first consideration was radiation- or breast cancer metastasis-derived BP. Clinical examination was performed. Finally, a diagnosis of MPNST of the brachial plexus was made, which guided an accurate treatment plan. This report highlights the importance of correctly diagnosing BP etiology for guiding precise treatment. BP caused by MPNST needs to be considered in clinical practice, and biopsy plays a central role in the differential diagnosis. Complete local surgical resection can prolong survival of patients with MPNST and improve treatment prognosis.

Analysis of treatment sequence and outcomes in patients with relapsed malignant peripheral nerve sheath tumors

Background

Malignant peripheral nerve sheath tumors (MPNST) are aggressive soft tissue sarcomas originating from cellular components within the nerve sheath. The incidence of MPNST is highest in people with neurofibromatosis type 1 (NF1), and MPNST is the leading cause of death for these individuals. Complete surgical resection is the only curative therapeutic option, but is often unfeasible due to tumor location, size, or presence of metastases. Evidence-based choices of chemotherapy for recurrent/refractory MPNST remain elusive. To address this gap, we conducted a retrospective analysis of our institutional experience in treating patients with relapsed MPNST in order to describe patient outcomes related to salvage regimens.

Methods

We conducted a retrospective electronic health record analysis of patients with MPNST who were treated at Johns Hopkins Hospital from January 2010 to June 2021. We calculated time to progression (TTP) based on salvage chemotherapy regimens.

Results

Sixty-five patients were included in the analysis. Upfront therapy included single or combined modalities of surgery, chemotherapy, or radiotherapy. Forty-eight patients received at least 1 line of chemotherapy, which included 23 different regimens (excluding active clinical studies). Most patients (n = 42, 87.5%) received a combination of doxorubicin, ifosfamide, or etoposide as first-line chemotherapy. Salvage chemotherapy regimens and their TTP varied greatly, with irinotecan/temozolomide-based regimens having the longest average TTP (255.5 days, among 4 patients).

Conclusions

Patients with advanced or metastatic MPNST often succumb to their disease despite multiple lines of therapy. These data may be used as comparative information in decision-making for future patients and clinical trials.

Investigation of Ultrasound Parameters for the Differential Diagnosis of Malignant and Benign Peripheral Nerve Sheath Tumors

OBJECTIVES

The objectives were to identify the key features of malignant and benign peripheral nerve sheath tumors (PNSTs) and determine a strategy for differentiating them using sonography.

METHODS

Forty-six malignant peripheral nerve sheath tumors (MPNSTs) and 83 benign peripheral nerve sheath tumors (BPNSTs) confirmed by pathology from April 2010 to July 2021 were included. The general data and grayscale and color Doppler ultrasonic manifestations were compared between the two groups. We used single factor, multifactor, and area under the receiver operating characteristic (ROC) curve analyses to extract significant malignant risk factors and then established a scoring system with these factors.

RESULTS

The significant variables identified in univariate analysis (P < .05) were maximum diameter, location, shape, boundary, encapsulation, echogenicity, texture pattern, calcification, entering or exiting nerve, and vascularity. Shape, boundary and vascularity were significant risk factors, and a scoring system was established. The area under the ROC curve (0.925) confirmed the usefulness of the scoring system for differentiating MPNSTs and BPNSTs.

CONCLUSIONS

Ultrasonography is an effective method for differentiating MPNSTs from BPNSTs.

Secretome analysis of human schwann cells derived from malignant peripheral nerve sheath tumor

Malignant peripheral nerve sheath tumors (MPNSTs) are highly aggressive, nerve-associated tumors and the main cause of death amongst neurofibromatosis type I (NF1) patients. Schwann cells (SCs) are the pathogenic cell type in MPNST, however the secretome of human MPNST -derived SCs is poorly defined. In this study, a comprehensive proteomic analysis of the proteins secreted by the sNF96.2 human SC line, derived from a patient with MPNST, was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A total of 17,354 unique peptides corresponding to 1538 individual proteins were identified. Among them, 995 proteins were confirmed as secreted using various bioinformatics tools including SignalP, SecretomeP, Vertebrate Secretome Database (VerSeDa), and Ingenuity Pathway Analysis (IPA). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment were conducted to assign protein localization and function, and to define enriched pathways. Protein binding was the most enriched molecular function, and the most enriched biological process was cell-cell adhesion. Metabolic pathways showed the highest levels of enrichment. In addition, 13 of the identified proteins were validated in Western blotting. This comprehensive secretome map constitutes a reference library providing a new molecular insight into MPNST.

Soft tissue sarcoma in adolescent and young adult patients: a retrospective study using a nationwide bone and soft tissue tumor registry in Japan

OBJECTIVE

The relationship between the adolescent and young adult age groups and poor overall survival in soft tissue sarcoma and the risk factors for poor outcomes in adolescent and young adult patients with soft tissue sarcoma were analyzed.

METHODS

The medical records of 7759 Japanese patients diagnosed with soft tissue sarcoma from 2006-13 were accessed from the Bone and Soft Tissue Tumor registry. The epidemiological features of adolescent and young adult patients were compared with those of other age groups. The cancer survival rates were calculated using the Kaplan-Meier method. The prognostic factors for cancer survival were analyzed with the Cox proportional hazards models. The primary endpoint for prognosis was tumor-related death.

RESULTS

There were 210 children, 1467 adolescent and young adults, 2771 adults and 3311 elderly among the 7759 patients identified with soft tissue sarcoma. Compared with other age groups, the proportions of myxoid/round cell liposarcoma, synovial sarcoma, malignant peripheral nerve sheath tumor, primitive neuroectodermal tumor and rhabdomyosarcoma in adolescent and young adult patients were the highest, but none was significantly more prevalent in adolescent and young adult patients. On multivariate analysis, age was not a prognostic factor for poor cancer survival among adolescent and young adult patients with soft tissue sarcoma. The cancer survival rates of adolescent and young adult patients with malignant peripheral nerve sheath tumor were poorer than those of the other age groups; however, adolescent and young adult age was not a prognostic factor on multivariate analysis in malignant peripheral nerve sheath tumor patients.

CONCLUSIONS

Our study is the first to investigate soft tissue sarcoma in adolescent and young adult patients using the nationwide Bone and Soft Tissue Tumor registry. Adolescent and young adult age is not a prognostic factor for poor cancer survival among those with soft tissue sarcoma in Japan.

Severe Phenotype in Patients with Large Deletions of NF1

Complete deletion of the NF1 gene is identified in 5-10% of patients with neurofibromatosis type 1 (NF1). Several studies have previously described particularly severe forms of the disease in NF1 patients with deletion of the NF1 locus, but comprehensive descriptions of large cohorts are still missing to fully characterize this contiguous gene syndrome. NF1-deleted patients were enrolled and phenotypically characterized with a standardized questionnaire between 2005 and 2020 from a large French NF1 cohort. Statistical analyses for main NF1-associated symptoms were performed versus an NF1 reference population. A deletion of the NF1 gene was detected in 4% (139/3479) of molecularly confirmed NF1 index cases. The median age of the group at clinical investigations was 21 years old. A comprehensive clinical assessment showed that 93% (116/126) of NF1-deleted patients fulfilled the NIH criteria for NF1. More than half had café-au-lait spots, skinfold freckling, Lisch nodules, neurofibromas, neurological abnormalities, and cognitive impairment or learning disabilities. Comparison with previously described "classic" NF1 cohorts showed a significantly higher proportion of symptomatic spinal neurofibromas, dysmorphism, learning disabilities, malignancies, and skeletal and cardiovascular abnormalities in the NF1-deleted group. We described the largest NF1-deleted cohort to date and clarified the more severe phenotype observed in these patients.

Malignant Peripheral Nerve Sheath Tumor of the Cerebellar Hemisphere: An Unusual Location and Multiple Intracranial Parenchyma Metastases

Malignant peripheral nerve sheath tumors (MPNSTs) are rare soft tissue malignancies that can occur in any part of the body. The most common sites are the proximal limbs and trunk. Intracranial MPNSTs are rare; most originate from the auditory, trigeminal, and other cranial nerves, and occurrence within the brain parenchyma is rarer. Here, we describe a malignant peripheral schwannoma in the cerebellar hemisphere of the brain parenchyma. To our knowledge, this is the first case of brain parenchymal metastasis of an MPNST. We observed no effects on the tumor after the application of multiple chemotherapy drugs; thereafter, we explored the literature surrounding the condition.

Repetitive syncope caused by a rare massive sporadic malignant peripheral nerve sheath tumor involving carotid arteries: A case report

RATIONALE

Malignant peripheral nerve sheath tumors (MPNSTs) are rare sarcomas arising from peripheral nerves. MPNSTs are uncommon in the head and neck, and various clinical manifestation often make the diagnosis challenging.

PATIENT CONCERNS

A 67-year-old female was referred for evaluation of repetitive syncope with a massive mass in the neck. Preoperative evaluation revealed potential neuroendocrine activity of the mass and enhanced computed tomography showed carotid artery was involved.

DIAGNOSIS

According to the preoperative imaging, intraoperative finding and postoperative pathological examination, the diagnosis of left neck MPNST involving left carotid arteries was made.

INTERVENTIONS

Volume expansion therapy with phenoxybenzamine started one week before surgery. Complete surgical resection of the mass was performed and pathological analysis suggested the diagnosis of MPNST. The postoperative radiotherapy was not given due to her poor nutrition.

OUTCOMES

This patient recovered well after surgery and no sign of recurrence was noted at 2-year follow-up.

LESSONS

Though the involvement of carotid artery with neuroendocrine activity is rare in sporadic MPNST, preoperative scanning of blood and urine catecholamine is crucial for intraoperative hemodynamic stability, especially when carotid artery is involved.

Prognostic Significance of Immunohistochemical Markers and Genetic Alterations in Malignant Peripheral Nerve Sheath Tumors: A Systematic Review

Background

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft tissue sarcomas with dismal prognosis. Pathological and genetic markers may predict more aggressive behavior in MPNSTs but have uncommonly been investigated, and few are used in daily practice. This study reviews the prognostic value of immunohistochemical markers and genetic alterations in MPNST.

Methods

A systematic search was performed in PubMed and Embase databases according to the PRISMA guidelines. Search terms related to ‘MPNST’ and ‘prognostic’ were used. Studies investigating the association of immunohistochemical markers or genetic alterations with prognosis were included. Qualitative synthesis was performed on all studies. A distinction was made between univariable and multivariable associations.

Results

Forty-six studies were included after full-text screening. Sixty-seven different immunohistochemical markers were investigated. Absence of S100 and H3K27me3 and high Ki67 and p53 staining was most commonly independently associated with worse survival and disease-free survival. Several genetic alterations were investigated as well with varying association to survival. TP53, CDK4, RASSF1A alterations were independently associated with worse survival, as well as changes in chromosomal length in Xp, 10q, and 16p.

Conclusions

MPNSTs harbor complex and heterogeneous biology. Immunohistochemical markers and genetic alterations have variable prognostic value. Absence of S100 and H3K27me3 and increased Ki67 can be of prognostic value. Alterations in TP53 or increase in p53 staining may distinguish MPNSTs with worse outcomes. Genetic alterations and staining of other cell cycle regulatory and Ras pathway proteins may also help stratifying patients with worse outcomes. A combination of markers can increase the prognostic value.

Phase II clinical trial of pazopanib for patients with unresectable or metastatic malignant peripheral nerve sheath tumors

Malignant peripheral nerve sheath tumor (MPNST) often does not respond well to chemotherapy and develops against a background of NF1. The purpose of our study was to examine the efficacy of pazopanib against MPNST. Our study was designed as a physician-initiated phase II clinical trial in patients with advanced MPNST. Patients were registered from 11 large hospitals. The primary endpoint was set to clarify the clinical benefit rate (CBR) at 12 weeks according to response evaluation criteria in solid tumors (RECIST). Progression-free survival (PFS), overall survival (OS) and the CBR based on modified Choi evaluation at week 12 were set as secondary endpoints along with treatment-related safety. The study enrolled 12 patients. Median age was 49 years. Seven had Grade 2 and five Grade 3 according to the FNCLCC evaluation. Median follow-up period was 10.6 months. CBR at 12 weeks was both 50.0% (RECIST and Choi). The median PFS was 5.4 months for both RECIST and Choi, and the median OS was 10.6 months. Of special interest, the median PFS was 2.9 months for patients with FNCLCC Grade 2 and 10.2 months for Grade 3 (both RECIST and Choi). Grade 4 adverse events of neutropenia and lipase elevation were noted in one patient each. The results of this pazopanib therapy were generally better than those of any of the other single molecular targeted therapies reported previously. Although accumulation of more cases remains necessary, we conclude pazopanib treatment for MPNST to be a safe and promising treatment after doxorubicin-based chemotherapy.

BRAF mutation, TERT promoter mutation, and HER2 amplification in sporadic or neurofibromatosis-related neurofibromas and malignant peripheral nerve sheath tumors: do these molecules have a signature in malignant transformation?

Peripheral nerve sheath tumors may occur sporadically or related to neurofibromatosis (NF). Unless the mechanisms of tumorigenesis in NF related malignant peripheral nerve sheath tumors (MPNST) are better understood, it remained unclear in sporadic cases. We aimed to investigate the genetic route for malignancy in both individuals with NF-1 and sporadic ones to open a way for targeted therapies in the future. We investigated the role of HER2 with Dual ISH DNA Probe Cocktail test, BRAF mutation (exon 15) and TERT promoter mutation frequency with Sanger sequencing method in respectively 25 sporadic neurofibromas, 25 NF-1 related neurofibromas and 25 MPNST cases from two institutes. Categorical data were analyzed and summarized as frequency and percentage. Statistical analysis was done with SPSS v.22 statistical package, and the statistical significance level was considered as 0.05. We identified TERT promoter mutation only in one sporadic MPNST (4%) and no BRAF mutation in any case. HER2 amplification is found in 10/25 (40%) MPNST cases. No mutations or gene amplification detected in neurofibromas (p < 0.001). MPNSTs are sarcomas with poor prognosis and limited treatment options. TERT promoter mutations and HER2 amplification may play a putative role in therapeutic purposes.

New Model Systems and the Development of Targeted Therapies for the Treatment of Neurofibromatosis Type 1-Associated Malignant Peripheral Nerve Sheath Tumors

Neurofibromatosis Type 1 (NF1) is a common genetic disorder and cancer predisposition syndrome (1:3000 births) caused by mutations in the tumor suppressor gene NF1. NF1 encodes neurofibromin, a negative regulator of the Ras signaling pathway. Individuals with NF1 often develop benign tumors of the peripheral nervous system (neurofibromas), originating from the Schwann cell linage, some of which progress further to malignant peripheral nerve sheath tumors (MPNSTs). Treatment options for neurofibromas and MPNSTs are extremely limited, relying largely on surgical resection and cytotoxic chemotherapy. Identification of novel therapeutic targets in both benign neurofibromas and MPNSTs is critical for improved patient outcomes and quality of life. Recent clinical trials conducted in patients with NF1 for the treatment of symptomatic plexiform neurofibromas using inhibitors of the mitogen-activated protein kinase (MEK) have shown very promising results. However, MEK inhibitors do not work in all patients and have significant side effects. In addition, preliminary evidence suggests single agent use of MEK inhibitors for MPNST treatment will fail. Here, we describe the preclinical efforts that led to the identification of MEK inhibitors as promising therapeutics for the treatment of NF1-related neoplasia and possible reasons they lack single agent efficacy in the treatment of MPNSTs. In addition, we describe work to find targets other than MEK for treatment of MPNST. These have come from studies of RAS biochemistry, in vitro drug screening, forward genetic screens for Schwann cell tumors, and synthetic lethal screens in cells with oncogenic RAS gene mutations. Lastly, we discuss new approaches to exploit drug screening and synthetic lethality with NF1 loss of function mutations in human Schwann cells using CRISPR/Cas9 technology.

Malignant peripheral nerve sheath tumor of nasal cavity and paranasal sinus with 13 years of follow-up-A case report and review of literature

Although extremely rare, sarcomas including malignant peripheral nerve sheath tumors should be considered in the differential diagnosis of sino-nasal tract lesions. Long-term cure is possible through definitive operative management followed by adjuvant therapy.

Combinatorial therapeutic targeting of BMP2 and MEK-ERK pathways in NF1-associated malignant peripheral nerve sheath tumors

The clinical management of malignant peripheral nerve sheath tumors (MPNSTs) is challenging not only due to its aggressive and invasive nature, but also limited therapeutic options. Using gene expression profiling, our lab identified BMP2-SMAD1/5/8 pathway as a potential therapeutic target for treating MPNSTs. In this study, we explored the therapeutic impact of targeting BMP2-SMAD1/5/8 pathway in conjunction with RAS-MEK-ERK signaling, which is constitutively activated in MPNSTs. Our results indicated that single agent treatment with LDN-193189, a BMP2 Type I receptor inhibitor, did not affect the growth and survival of MPNST cells at biochemically relevant inhibitory concentrations. However, addition of a MEK1/2 inhibitor, selumetinib, to LDN-193189-treated cells resulted in significant inhibition of cell growth and induction of cell death. LDN-193189 at biochemically effective concentrations significantly inhibited motility and invasiveness of MPNST cells, and these effects were enhanced by the addition of selumetinib. Overall, our results advocate for a combinatorial therapeutic approach for MPNSTs that not only targets the growth and survival via inhibition of MEK1/2, but also its malignant spread by suppressing the activation of BMP2-SMAD1/5/8 pathway. Importantly, these studies were conducted in low-passage patient-derived MPNST cells, allowing for an investigation of the effects of the proposed drug treatments in a biologically-relevant context.

Salvage rates and prognostic factors after relapse in children and adolescents with malignant peripheral nerve sheath tumors

BACKGROUND

Malignant peripheral nerve sheath tumor (MPNST) is one of the most common nonrhabdomyosarcoma soft tissue sarcomas encountered in pediatric age, and it is generally characterized by poor outcome, particularly for relapsing patients.

MATERIALS AND METHODS

This study considered 73 patients <21 years of age with relapsing MPNST observed among 120 patients enrolled in Italian pediatric protocols from 1979 to 2004. With the aim of possibly establishing a risk-adapted stratification, patients' outcome was examined using univariate and multivariate analysis based on clinical features at onset, first-line treatments, clinical findings at the time of first relapse, and second-line treatments.

RESULTS

The time to relapse ranged from 1 to 204 months after first diagnosis (median 7 months). The first relapse event was mainly local. At the time of our analysis, nine patients were alive in remission. The median overall survival after first relapse was 11 months, and the survival rates were 39.2% at 1 year and 15.8% at 5 years. The factors revealing the greatest impact on prognosis were as follows: initial tumor invasiveness, time of relapse, and achievement of a secondary complete remission (which was related to the feasibility of radical surgery).

CONCLUSIONS

Our study confirmed the unsatisfactory prognosis for pediatric patients with relapsing MPNST and pointed to a risk-adapted stratification model for the purposes of deciding second-line treatments. For the time being, an aggressive surgical approach seems to be the only effective salvage treatment and should be recommended. New therapeutic approaches are under evaluation with a view to improving current outcomes.

Fluorine-18-2-fluoro-2-deoxy-D-glucose Positron Emission Tomography/Computed Tomography Masquerading as a Case of Sporadic Malignant Peripheral Nerve Sheath Tumor of Lower Extremity Presenting as Massive Lower Limb Edema

Malignant peripheral nerve sheath tumors (MPNSTs) are rare neuroectodermal tumors resulting from the malignant transformation of benign plexiform neurofibromas. The sporadic form of these tumors is rare than familial variants (seen in neurofibromatosis Type 1) and making the diagnosis difficult. We are presenting a case of 40--year-old female with the complaint of progressive swelling of lower limb with initial suspicion of lymphedema and underwent lymphoscintigraphy, magnetic resonance imaging, and finally fluorine-18-2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography scans were done to rule out mitotic etiology and extent of the disease. The patient underwent below-knee amputation, and histopathological examination confirmed the diagnosis of sporadic MPNST.

Metastatic Epithelioid Malignant Peripheral Nerve Sheath Tumor in a Known Case of Neurofibromatosis-1, Cytomorphological Appearance, and Critical Analysis of Immunohistochemistry

Malignant peripheral nerve sheath tumors (MPNSTs) are rare soft tissue tumors commonly arising from nerve roots in the extremities with a predilection in neurofibromatosis (NF) patients. MPNSTs are known to behave aggressively, with worse prognosis in nonresectable cases, and a 5-year survival of about 52% and 15% in resectable and unresectable cases, respectively. Although cytological diagnosis in a known case of NF-1 is possible, however, in the absence of any associated syndrome in a sporadic case, it is very challenging to accurately diagnose this tumor. Till date, to the best of our knowledge, only three cases of epithelioid MPNST correctly diagnosed on cytological examination have been described. We are presenting another case of epithelioid MPNST in a 40-year-old patient with stigmata of NF-1 since childhood, diagnosed on fine-needle aspiration cytology from the left flank mass with subsequent histopathology from left inguinal lymph node metastasis.

Unusual CT Appearance of Bony Metastases from Malignant Peripheral Nerve Sheath Tumor

We present a case of bone metastases from a malignant peripheral nerve sheath tumor (MPNST). While multiple bone lesions typically are suggestive of metastatic disease, especially in combination with a primary tumor and positive PET, the appearance of lesions in this patient was quite atypical. We are not aware of any case of metastatic disease with such atypical doughnut appearance as in our case.

Reconstruction of an Extensive Midfacial Defect Using Additive Manufacturing Techniques

Malignant peripheral nerve sheath tumors are extremely rare tumors arising in peripheral nerves. Only 17 cases involving the trigeminal nerve have ever been reported. These tumors have a very poor prognosis and very high rates of recurrence and metastases. Their recommended treatment involves complete tumor resection followed by radiation. This can be problematic in the head and neck region. We present a clinical case involving a 33-year-old female patient presenting with a slow-growing, exophytic mass of the anterior maxilla. Incisional biopsy and subsequent histological examination revealed a diagnosis of a malignant peripheral nerve sheath tumor. Surgical resection involved a complete maxillectomy, rhinectomy, and resection of the upper lip and aspects of the left and right cheeks. Reconstruction of the subsequent defect incorporated the placement of four zygomatic oncology implants to aid in retention of a facial prosthesis. These implants, however, were subsequently lost; and an anatomical model of the hard tissues was manufactured via 3D printing. This model was used to design and manufacture a titanium frame (customized implant) for the patient. The frame was then fixated and secured intraoperatively with 21 cortical screws. A maxillary denture and silicone facial prosthesis were also made to fit onto this frame. This is the first known case where additive manufacturing, via the use of rapid prototyping and 3D printing, was employed to manufacture a facial prosthesis.

Triterpenoid saponin flaccidoside II from Anemone flaccida triggers apoptosis of NF1-associated malignant peripheral nerve sheath tumors via the MAPK-HO-1 pathway

Malignant peripheral nerve sheath tumors (MPNSTs) are highly aggressive soft tissue neoplasms that are extremely rare and are frequently associated with neurofibromatosis type 1 patients. MPNSTs are typically fatal, and there is no effective treatment so far. In our previous study, we showed that flaccidoside II, one of the triterpenoid saponins isolated from Anemone flaccida Fr. Schmidt, has antitumor potential by inducing apoptosis. In the present study, we found that flaccidoside II inhibits proliferation and facilitates apoptosis in MPNST cell lines ST88-14 and S462. Furthermore, this study provides a mechanism by which the downregulation of heme oxygenase-1 via extracellular signal-regulated kinase-1/2 and p38 mitogen-activated protein kinase pathways is involved in the apoptotic role of flaccidoside II. This study suggested the potential of flaccidoside II as a novel pharmacotherapeutic approach for MPNSTs.

[Mass on the neck]

Malignant peripheral nerve sheath tumors (MPNST) are rare. But especially in patients with known neurofibromatosis type 1 (von Recklinghausen), this entity of tumors should not be forgotten. The indication for open biopsy or excision should be made generously. In the following, we report a rare case of MPNST, which highlights the importance of rapid diagnosis and treatment.

Neurofibromatosis type 1 and malignancy in childhood

Neurofibromatosis type 1 (NF1) is an autosomal dominant hereditary neurocutaneous syndrome characterized by multi-system involvement and an increased incidence of both benign and malignant tumors. In this study, we evaluated the clinical presentation and prognosis of NF1 and malignancy. Between 1975 and 2013, 26 (5%) of the 473 patients with NF1 at our center developed non-neurofibroma neoplasms. The patient files of 26 subjects with tumors, other than optic glioma, were analyzed retrospectively to evaluate clinical features and treatment results. The age at diagnosis of NF1 ranged from 3 months to 16 years (median 5.5 years). The age range at tumor diagnosis was 1.5-33 years (median 8 years) in these 26 patients. The tumor histological subtypes included the following: 12 soft-tissue tumors (6 malignant peripheral nerve sheath tumors (MPNST), 5 rhabdomyosarcomas (RMS) and 1 malignant fibrous histiocytoma), 11 brain tumors (6 low-grade gliomas, 3 high-grade gliomas, and 2 medulloblastoma), 2 neuroblastomas and 1 non-Hodgkin's lymphoma. Twelve of 26 patients were alive at the time of the study. Although benign brain tumors with NF1 are more common, high-grade brain tumors also occur. Thus, careful and regular follow-up is crucial for early detection of malignancy in NF1 patients.

Modern surgical techniques for management of soft tissue sarcomas involving the spine: outcomes and complications

Several types of soft tissue sarcomas may locally extend to the spine. The best therapeutic strategy for such lesions strongly depends on the histological diagnosis. In this article the authors provide an up-to-date review of current guidelines regarding the management of soft tissue sarcomas involving the spine. Special attention is given to outcomes and complications of modern surgical series in order to highlight current challenges in the management of such lesions.

Malignant peripheral nerve sheath tumors (MPNST): a SEER analysis of incidence across the age spectrum and therapeutic interventions in the pediatric population

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNST) are very rare in the general population and challenging to treat. A paucity of data exists regarding the incidence of MPNST across all age groups and treatment outcomes in the pediatric population. We aimed to characterize both using the Survival, Epidemiology, and End Results (SEER) database.

PROCEDURE

The SEER-18 database with information on the United States population from 1973 to 2009 was queried for cases of MPNST. For incidence data, 1,182 cases were found among the general population. Of those, 165 cases were in individuals aged 0-19. After exclusions, 139 cases from the SEER-18 database met study criteria for outcomes analysis. For each patient, variables including gender, age, race, stage (localized, regional, or distant), surgical treatment, and radiotherapy were obtained.

RESULTS

The overall incidence of MPNST was 1.46 per million person-years, with increased incidence among the elderly. In the pediatric population, the incidence was 0.56 per million person-years, and was higher among post-pubertal children aged 10-19. Median overall survival in the pediatric population was 30 months, with only localized disease and treatment with surgery being positive prognostic factors on multivariate analysis.

CONCLUSIONS

MPNST is a rare disease and, among children, is most frequent seen in adolescents. Surgery is crucial as first-line treatment for MPNST, especially if the tumor is localized at diagnosis. In patients with non-localized MPNST, the disease remains extremely difficult to manage, and both surgery and radiotherapy are interventions that should be considered.

Co-targeting the MAPK and PI3K/AKT/mTOR pathways in two genetically engineered mouse models of schwann cell tumors reduces tumor grade and multiplicity

Malignant peripheral nerve sheath tumors (MPNSTs) are soft tissue sarcomas that occur spontaneously, or from benign plexiform neurofibromas, in the context of the genetic disorder Neurofibromatosis Type 1 (NF1). The current standard treatment includes surgical resection, high-dose chemotherapy, and/or radiation. To date, most targeted therapies have failed to demonstrate effectiveness against plexiform neurofibromas and MPNSTs. Recently, several studies suggested that the mTOR and MAPK pathways are involved in the formation and progression of MPNSTs. Everolimus (RAD001) inhibits the mTOR and is currently FDA approved for several types of solid tumors. PD-0325901 (PD-901) inhibits MEK, a component of the MAPK pathway, and is currently in clinical trials. Here, we show in vitro than MPNST cell lines are more sensitive to inhibition of cellular growth by Everolimus and PD-901 than immortalized human Schwann cells. In combination, these drugs synergistically inhibit cell growth and induce apoptosis. In two genetically engineered mouse models of MPNST formation, modeling both sporadic and NF1-associated MPNSTs, Everolimus, or PD-901 treatment alone each transiently reduced tumor burden and size, and extended lifespan. However, prolonged treatment of each single agent resulted in the development of resistance and reactivation of target pathways. Combination therapy using Everolimus and PD-901 had synergistic effects on reducing tumor burden and size, and increased lifespan. Combination therapy allowed persistent and prolonged reduction in signaling through both pathways. These data suggest that co-targeting mTOR and MEK may be effective in patients with sporadic or NF1-associated MPNSTs.

18F-fluorodeoxyglucose positron emission tomography/computed tomography in a case of malignant peripheral nerve sheath tumor: An unusual presentation

Malignant peripheral nerve sheath tumors (MPNSTs) are rare tumors, with an estimated incidence of 0.1/100,000/year. They are regarded as a rare variety of soft-tissue sarcomas that derive from peripheral nerves or from cells associated with the nerve sheath. Until 50% of observed MPNSTs occur in patients with neurofibromatosis 1 (NF1). The typical presenting signs and symptoms of a PNST are a palpable mass involving a peripheral nerve, loss of nerve function and/or pain. Recently, positron emission tomography (PET) has been used to detect 18F-fluorodeoxyglucose uptake in these tumors. Most of the PET studies have been reported in patients with NF1. We report a case of sporadic MPNST masquerading as infectious dermatoses, with an unusual PET/computed tomography presentation.

Intrathoracic malignant peripheral nerve sheath tumors: imaging features and implications for management

Background

The aim of the study was to analyze the clinical and imaging characteristics of primary intrathoracic malignant peripheral nerve sheath tumors (MPNSTs).

Patients and methods.

In this institutional review board (IRB)-approved retrospective study, clinical and imaging features of 15 patients (eight men; mean age 50 years [range 18–83)] with pathologically proven malignant peripheral nerve sheath tumors seen from January 1999 to December 2011 were analyzed. Imaging features (CT in 15, MRI in 5 and PET/CT in 4) of primary tumors were evaluated by three radiologists and correlated with clinical management.

Results

Of the 15 tumors, six were located in the mediastinum (two each in anterior, middle and posterior mediastinum), four in chest wall, two were paraspinal, and three in the lung. Four patients had neurofibromatosis-1 (NF1); four tumors had heterologous rhabdomyoblastic differentiation (malignant triton tumor). Masses typically were elongated along the direction of nerves, with mean size of 11 cm. The masses were hypo- or isodense to muscles on CT, isointense on T1-weighted images, hyperintense on T2-weighted images and intensely fluorodeoxyglucose (FDG) avid (mean standardized uptake value [SUV]_max of 10.5 [range 4.4–23.6]). Necrosis and calcification was seen in four tumors each. Finding of invasion of adjacent structures on imaging led to change in management in seven patients; patients with invasion received chemoradiation.

Conclusions

Intrathoracic MPNSTs appear as large elongated masses involving mediastinum, lung or chest wall. Radiological identification of invasion of adjacent structures is crucial and alters therapy, with patients with invasion receiving neoadjuvant or adjuvant chemoradiation.

Common genetic variants in the microRNA biogenesis pathway are associated with malignant peripheral nerve sheath tumor risk in a Chinese population

PURPOSE

The role of microRNAs (miRNAs) in tumorigenesis has been well established. Genetic variants in the miRNA biogenesis pathway genes may modify cancer development and survival by affecting the miRNA biogenesis. Our aim is to investigate the association of polymorphisms in the miRNA biogenesis pathway genes and malignant peripheral nerve sheath tumor (MPNST) risk among neurofibromatosis type 1 (NF1) patients.

METHODS

A case-control study was performed to analyze 53 SNPs in 11 miRNA biogenesis pathway genes in 356 patients (200 patients with NF1 and 156 patients with both NF1 and MPNST) in China. Association analysis was performed in an additive genetic model by logistics regression.

RESULTS

Four SNPs (DDX5 rs1991401, OR=1.79, 95% CI, 1.34-2.38, P=7.90 × 10(-5); DROSHA rs10719, OR=1.64, 95% CI, 1.23-2.20, P=8.76 × 10(-4); AGO2 rs7005286, OR=0.48, 95% CI, 0.32-0.72, P=3.46 × 10(-4); GEMIN4 rs7813, OR=0.50, 95% CI, 0.34-0.72, P=2.65 × 10(-4)) were significantly associated with MPNST risk. A strong gene-dose effect with increased MPNST risk (P for trend<0.001) was observed.

CONCLUSIONS

Genetic variants in the miRNA biogenesis pathway genes may modify MPNST risk both individually and jointly.