Radiation-induced and neurofibromatosis-associated malignant peripheral nerve sheath tumors (MPNST) have worse outcomes than sporadic MPNST

Malignant peripheral nerve sheath tumor mimicking carotid body tumor, a rare case report and review of literature

INTRODUCTION AND IMPORTANCE

Malignant Peripheral Nerve Sheath Tumor (MPNST) is a rare type of soft tissue sarcoma. It is an aggressive tumor with high rates of local recurrence and distant metastasis. MPNST rarely occurs in the neck. We present a case of cervical MPNST manifesting as Carotid Body Tumor (CBT).

CASE PRESENTATION

A 67-year-old man presented with a neck mass. The mass was rapidly enlarging and imaging studies favored CBT. A previous attempt at surgical resection failed, and the compressive symptoms were progressive during recent weeks. After multidisciplinary discussion, the tumor was resected and pathological evaluation confirmed the diagnosis of MPNST. Post-operative metastatic work-up showed lung metastasis, and the patient died approximately one year after surgery.

CLINICAL DISCUSSION

Cervical MPNST is rare, and surgery is the mainstay of its treatment. Pre-operative tissue diagnosis is recommended when possible, and immunohistochemical staining is necessary for prompt diagnosis. Adjuvant therapy may be helpful in metastatic cases or incomplete resection. Nevertheless, local recurrence and distant metastasis especially to the lungs are common, as in our case.

CONCLUSION

MPNST is one of the potential causes of cervical masses and considering its invasive behavior, surgical resection is recommended as soon as the diagnosis is made.

Targeting the peripheral neural-tumour microenvironment for cancer therapy

As the field of cancer neuroscience expands, the strategic targeting of interactions between neurons, cancer cells and other elements in the tumour microenvironment represents a potential paradigm shift in cancer treatment, comparable to the advent of our current understanding of tumour immunology. Cancer cells actively release growth factors that stimulate tumour neo-neurogenesis, and accumulating evidence indicates that tumour neo-innervation propels tumour progression, inhibits tumour-related pro-inflammatory cytokines, promotes neovascularization, facilitates metastasis and regulates immune exhaustion and evasion. In this Review, we give an up-to-date overview of the dynamics of the tumour microenvironment with an emphasis on tumour innervation by the peripheral nervous system, as well as current preclinical and clinical evidence of the benefits of targeting the nervous system in cancer, laying a scientific foundation for further clinical trials. Combining empirical data with a biomarker-driven approach to identify and hone neuronal targets implicated in cancer and its spread can pave the way for swift clinical integration.

Recurrent sporadic malignant triton tumor in the carotid sheath in the absence of neurofibromatosis

Malignant Triton Tumors (MTTs) are a rare and aggressive subtype of malignant peripheral nerve sheath tumors (MPNSTs), often associated with neurofibromatosis type 1. This case report describes a unique instance of recurrent sporadic MTT within the carotid sheath in a 33-year-old male without any personal or familial history of neurofibromatosis. The patient initially presented with a biopsy-confirmed MTT in the right neck, involving the carotid body and brachial plexus, and underwent partial resection, radiation therapy, and chemotherapy. Six months later, the patient presented with recurrent MTT, and subsequently underwent radical tumor resection, segmental right carotid artery resection, and deep femoral vein interposition. Recovery was complicated by hematoma formation, and the patient developed vocal fold paralysis and a left vocal fold cyst, necessitating further surgeries. Yearly follow-ups for 8 years revealed no recurrence. This case emphasizes the importance of comprehensive patient evaluation, including clinical history, imaging, and biopsy findings, for accurate diagnosis and prompt surgical intervention in managing such rare and aggressive tumors. Further research is needed to identify novel therapies and improve survival rates for patients with MTTs.

An algorithmic approach to the management of peripheral nerve tumours

This article reviews the pathology and management of peripheral nerve tumours, including a framework for investigation and decision-making. Most tumours are benign, including schwannomas and neurofibromas, but malignant peripheral nerve sheath tumours can occur. The risk of malignant change is remote for schwannomas but higher for neurofibromas, particularly in neurofibromatosis type 1. Magnetic resonance imaging is useful for defining the relationship of a swelling with adjacent nerves but is not definitive for tissue diagnosis. Increasing size, pain and neurological deficit suggest malignant change and TruCut needle biopsy is indicated, although there is a risk of sampling error. Excision biopsy preserving nerve function may be carried out for benign tumours to relieve symptoms. Malignant tumours require a multidisciplinary approach. Complete surgical excision with clear margins is the only curative treatment and may be supplemented with radiotherapy and chemotherapy. However, prognosis remains poor, particularly for patients with neurofibromatosis.

Preoperative Classification of Peripheral Nerve Sheath Tumors on MRI Using Radiomics

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft-tissue tumors prevalent in neurofibromatosis type 1 (NF1) patients, posing a significant risk of metastasis and recurrence. Current magnetic resonance imaging (MRI) imaging lacks decisiveness in distinguishing benign peripheral nerve sheath tumors (BPNSTs) and MPNSTs, necessitating invasive biopsies. This study aims to develop a radiomics model using quantitative imaging features and machine learning to distinguish MPNSTs from BPNSTs. Clinical data and MRIs from MPNST and BPNST patients (2000-2019) were collected at a tertiary sarcoma referral center. Lesions were manually and semi-automatically segmented on MRI scans, and radiomics features were extracted using the Workflow for Optimal Radiomics Classification (WORC) algorithm, employing automated machine learning. The evaluation was conducted using a 100× random-split cross-validation. A total of 35 MPNSTs and 74 BPNSTs were included. The T1-weighted (T1w) MRI radiomics model outperformed others with an area under the curve (AUC) of 0.71. The incorporation of additional MRI scans did not enhance performance. Combining T1w MRI with clinical features achieved an AUC of 0.74. Experienced radiologists achieved AUCs of 0.75 and 0.66, respectively. Radiomics based on T1w MRI scans and clinical features show some ability to distinguish MPNSTs from BPNSTs, potentially aiding in the management of these tumors.

Update on immunohistochemistry in bone and soft tissue tumors: Cost-effectively replacing molecular testing with immunohistochemistry

Soft tissue tumors form part of a challenging domain in diagnostic pathology owing to their comparative rarity, astonishing histologic diversity, and overlap between entities. Many of these tumors are now known to be defined by highly recurrent, or, in some instances, unique molecular alterations. Insights from gene profiling continue to elucidate the wider molecular landscape of soft tissue tumors; many of these advances have been co-opted by immunohistochemistry (IHC) for diagnostic applications. There now exists a multitude of antibodies serving as surrogate markers of recurrent gene fusions, amplifications, and point mutations, which, in certain settings, can replace the need for more resource and time-intensive cytogenetic and molecular genetic analyses. IHC presents many advantages including rapid turnaround time, cost-effectiveness, and interpretative reproducibility. A sensible application of these immunohistochemical markers complemented by a working knowledge of the molecular pathogenesis of bone and soft tissue tumors permits accurate diagnosis in the majority of cases. In this review, we will outline some of these biomarkers while emphasizing molecular correlates and highlighting interpretative challenges and pitfalls.

NF1-Driven Rhabdomyosarcoma Phenotypes: A Comparative Clinical and Molecular Study of NF1-Mutant Rhabdomyosarcoma and NF1-Associated Malignant Triton Tumor

PURPOSE

Alterations of the NF1 tumor suppressor gene is the second most frequent genetic event in embryonal rhabdomyosarcoma (ERMS), but its associations with clinicopathologic features, outcome, or coexisting molecular events are not well defined. Additionally, NF1 alterations, mostly in the setting of neurofibromatosis type I (NF1), drive the pathogenesis of most malignant peripheral nerve sheath tumor with divergent RMS differentiation (also known as malignant triton tumor [MTT]). Distinguishing between these entities can be challenging because of their pathologic overlap. This study aims to comprehensively analyze the clinicopathologic and molecular spectrum of NF1-mutant RMS compared with NF1-associated MTT for a better understanding of their pathogenesis.

METHODS

We investigated the clinicopathologic and molecular landscape of a cohort of 22 NF1-mutant RMS and a control group of 13 NF1-associated MTT. Cases were tested on a matched tumor-normal hybridization capture-based targeted DNA next-generation sequencing.

RESULTS

Among the RMS group, all except one were ERMS, with a median age of 17 years while for MTT the mean age was 39 years. Three MTTs were misdiagnosed as ERMS, having clinical impact in one. The most frequent coexisting alteration in ERMS was TP53 abnormality (36%), being mutually exclusive from NRAS mutations (14%). MTT showed coexisting CDKN2A/B and PRC2 complex alterations in 38% cases and loss of H3K27me3 expression. Patients with NF1-mutant RMS exhibited a 70% 5-year survival rate, in contrast to MTT with a 33% 5-year survival. All metastatic NF1-mutant ERMS were associated with TP53 alterations.

CONCLUSION

Patients with NF1-mutant ERMS lacking TP53 alterations may benefit from dose-reduction chemotherapy. On the basis of the diagnostic challenges and significant treatment and prognostic differences, molecular profiling of challenging tumors with rhabdomyoblastic differentiation is recommended.

Local recurrence in malignant peripheral nerve sheath tumours: multicentre cohort study

BACKGROUND

Malignant peripheral nerve sheath tumours (MPNSTs) have high local recurrence (LR) rates. Literature varies on LR risk factors and treatment. This study aimed to elucidate treatment options and risk factors for first and second LRs (LR1 and LR2) in a large multicentre cohort.

METHOD

Surgically treated primary MPNSTs between 1988 and 2019 in the MONACO multicentre cohort were included. Cox regression analysed LR1 and LR2 risk factors and overall survival (OS) after LR1. Treatment of LR1 and LR2 was evaluated.

RESULTS

Among 507 patients, 28% developed LR1. Median follow-up was 66.9 months, and for survivors 111.1 months. Independent LR1 risk factors included high-grade tumours (HR 2.63; 95% c.i. 1.15 to 5.99), microscopically positive margins (HR 2.19; 95% c.i. 1.51 to 3.16) and large tumour size (HR 2.14; 95% c.i. 1.21 to 3.78). Perioperative radiotherapy (HR 0.62; 95% c.i. 0.43 to 0.89) reduced the risk. LR1 patients had poorer OS. Synchronous metastasis worsened OS (HR 1.79; 95% c.i. 1.02 to 3.14) post-LR1, while surgically treated LR was associated with better OS (HR 0.38; 95% c.i. 0.22 to 0.64) compared to non-surgical cases. Two-year survival after surgical treatment was 71% (95% c.i. 63 to 82%) versus 28% (95% c.i. 18 to 44%) for non-surgical LR1 patients. Most LR1 (75.4%) and LR2 (73.7%) patients received curative-intent treatment, often surgery alone (64.9% versus 47.4%). Radiotherapy combined with surgery was given to 11.3% of LR1 and 7.9% of LR2 patients.

CONCLUSION

Large, high-grade MPNSTs with R1 resections are at higher LR1 risk, potentially reduced by radiotherapy. Surgically treated recurrences may provide improved survival in highly selected cases.

Survival outcomes of malignant peripheral nerve sheath tumors (MPNSTs) with and without neurofibromatosis type I (NF1): a meta-analysis

INTRODUCTION

Malignant peripheral nerve sheath tumors (MPNSTs) are malignancies that demonstrate nerve sheath differentiation in the peripheral nervous system. They can occur sporadically or be associated with neurofibromatosis type 1 (NF1), an autosomal dominant neurocutaneous disorder, with up to 13% of patients developing MPNSTs in their lifetimes. Previous studies have suggested conflicting findings regarding the prognosis of NF1 for patients with MPNSTs. The elucidation of NF1 as an independent prognostic factor on mortality has implications for clinical management. We aim to investigate the role of NF1 status as an independent prognostic factor of overall survival (OS) and disease-specific survival (DSS) in MPNSTs.

METHODS

An electronic literature search of PubMed and MEDLINE was performed on studies reporting OS or DSS outcomes of MPNSTs with and without NF1. A grey literature search by reviewing bibliographies of included studies and review articles was performed to find pertinent studies. Data was extracted and assessed in accordance with the PRISMA guidelines. A meta-analysis was performed to calculate hazard ratios (HRs) using a random-effects model. The primary and secondary outcomes were all-cause and disease-specific mortality, respectively, with NF1 as an independent prognostic factor of interest.

RESULTS

A total of 59 retrospective studies involving 3602 patients fulfilled the inclusion criteria for OS analysis, and 23 studies involving 704 MPNST patients were included to evaluate DSS outcomes. There was a significant increase in the hazard of all-cause mortality (HR 1.63, 95% CI 1.45 to 1.84) and disease-specific mortality (HR 1.52, 95% CI 1.24 to 1.88) among NF1 as compared to sporadic cases. Subgroup analyses and meta-regression showed that this result was consistent regardless of the quality of the study and year of publication.

CONCLUSION

NF1 is associated with a substantially higher risk of all-cause and disease-specific mortality. This finding suggests that closer surveillance is required for NF1 patients at risk of developing MPNSTs.

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

Background

This study aimed to assess the performance of currently available risk calculators in a cohort of patients with malignant peripheral nerve sheath tumors (MPNST) and to create an MPNST-specific prognostic model including type-specific predictors for overall survival (OS).

Methods

This is a retrospective multicenter cohort study of patients with MPNST from 11 secondary or tertiary centers in The Netherlands, Italy and the United States of America. All patients diagnosed with primary MPNST who underwent macroscopically complete surgical resection from 2000 to 2019 were included in this study. A multivariable Cox proportional hazard model for OS was estimated with prespecified predictors (age, grade, size, NF-1 status, triton status, depth, tumor location, and surgical margin). Model performance was assessed for the Sarculator and PERSARC calculators by examining discrimination (C-index) and calibration (calibration plots and observed-expected statistic; O/E-statistic). Internal-external cross-validation by different regions was performed to evaluate the generalizability of the model.

Results

A total of 507 patients with primary MPNSTs were included from 11 centers in 7 regions. During follow-up (median 8.7 years), 211 patients died. The C-index was 0.60 (95% CI 0.53-0.67) for both Sarculator and PERSARC. The MPNST-specific model had a pooled C-index of 0.69 (95%CI 0.65-0.73) at validation, with adequate discrimination and calibration across regions.

Conclusions

The MPNST-specific MONACO model can be used to predict 3-, 5-, and 10-year OS in patients with primary MPNST who underwent macroscopically complete surgical resection. Further validation may refine the model to inform patients and physicians on prognosis and support them in shared decision-making.

Malignant and Benign Peripheral Nerve Sheath Tumors in a Single Center: Value of Clinical and Ultrasound Features for the Diagnosis of Malignant Peripheral Nerve Sheath Tumor Compared With Magnetic Resonance Imaging

OBJECTIVES

This study aimed to investigate the combined use of ultrasonography and clinical features for the differentiation of malignant peripheral nerve sheath tumors (MPNST) from benign peripheral nerve sheath tumors (BPNST) and to compare the efficacy of ultrasonography with that of magnetic resonance imaging (MRI).

METHODS

This retrospective study included 28 MPNSTs and a control group of 57 BPNSTs. All patients underwent an ultrasound scan using the Logiq E9 (GE Health Care, Milwaukee, WI) or EPIQ7 equipment (Philips Medical System, Bothell, WA). A 3.0-T MRI machine (Ingenia; Philips Healthcare, Best, the Netherlands) was used for scanning, and conventional MRI was performed on different regions based on the patient's clinical situation. The following variables were evaluated: palpable mass, pain, nerve symptoms, maximum diameter, location, shape, boundary, encapsulation, echogenicity, echo homogeneity, presence of a cystic component, calcification, target sign, posterior echo, and intertumoral vascularity of the tumors. The diagnostic efficacy of ultrasonography and clinical factors was compared with that of MRI. Independent factors for predicting MPNST versus BPNST were also assessed.

RESULTS

The parameters of location, shape, boundary, encapsulation, and vascularity were significantly different between MPNSTs and BPNSTs. Multiple logistic regression analysis showed that shape, boundary, and vascularity were independent predictors of MPNSTs. The sensitivity, specificity, and Youden index of the three clinical and ultrasound factors (shape, boundary, and vascularity) were 0.89, 0.81, and 0.69, respectively, whereas those of MRI were 0.71, 0.89, and 0.61, respectively. No significant differences in the area under the curve (AUC) of the three combined clinical and ultrasound factors and those of MRI were found (P > .05).

CONCLUSIONS

MRI was useful in the differential diagnosis between MPNSTs and BPNSTs. However, the combination of clinical and ultrasound diagnoses can achieve the same effect as MRI, including shape, boundary, and vasculature.

Germline Variants in Cancer Predisposition Genes in Pediatric Patients with Central Nervous System Tumors

Central nervous system (CNS) tumors comprise around 20% of childhood malignancies. Germline variants in cancer predisposition genes (CPGs) are found in approximately 10% of pediatric patients with CNS tumors. This study aimed to characterize variants in CPGs in pediatric patients with CNS tumors and correlate these findings with clinically relevant data. Genomic DNA was isolated from the peripheral blood of 51 pediatric patients and further analyzed by the next-generation sequencing approach. Bioinformatic analysis was done using an "in-house" gene list panel, which included 144 genes related to pediatric brain tumors, and the gene list panel Neoplasm (HP:0002664). Our study found that 27% of pediatric patients with CNS tumors have a germline variant in some of the known CPGs, like ALK, APC, CHEK2, ELP1, MLH1, MSH2, NF1, NF2 and TP53. This study represents the first comprehensive evaluation of germline variants in pediatric patients with CNS tumors in the Western Balkans region. Our results indicate the necessity of genomic research to reveal the genetic basis of pediatric CNS tumors, as well as to define targets for the application and development of innovative therapeutics that form the basis of the upcoming era of personalized medicine.

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.

The role of radiotherapy in the management of malignant peripheral nerve sheath tumors: a single-center retrospective cohort study

PURPOSE

This study sought to investigate the role of radiotherapy (RT) in addition to surgery for oncological outcomes in patients with malignant peripheral nerve sheath tumors (MPNST).

METHODS

In this single-center, retrospective cohort study, histopathologically confirmed MPNST were analyzed. Local control (LC), overall survival (OS), and distant metastasis-free survival (DMFS) were assessed using the Kaplan-Meier estimator. Multivariable Cox regression analysis was performed to identify factors associated with LC, OS, and DMFS.

RESULTS

We included 57 patients with a median follow-up of 20.0 months. Most MPNSTs were located deeply (87.5%), were larger than 5 cm (55.8%), and had high-grade histology (78.7%). Seventeen patients received surgery only, and 25 patients received surgery and pre- or postoperative RT. Median LC, OS, and DMFS after surgery only were 8.7, 25.5, and 22.0 months; after surgery with RT, the median LC was not reached, while the median OS and DMFS were 111.5 and 69.9 months. Multivariable Cox regression of LC revealed a negative influence of patients presenting with local disease recurrence compared to patients presenting with an initial primary diagnosis of localized MPNST (hazard ratio: 8.86, p = 0.003).

CONCLUSIONS

The addition of RT to wide surgical excision appears to have a beneficial effect on LC. Local disease recurrence at presentation is an adverse prognostic factor for developing subsequent local recurrences. Future clinical and translational studies are warranted to identify molecular targets and find effective perioperative combination therapies with RT to improve patient outcomes.

Ovarian epithelioid malignant peripheral nerve sheath tumor with EWSR1-CREM fusion: A case report and literature review

Epithelioid malignant peripheral nerve sheath tumor (EMPNST) is a rare soft tissue sarcoma. The authors report the first case of EMPNST arising in the ovary (OEMPNST). A 7-year-old child underwent left salpingo-oophorectomy due to tumor rupture and the pathology suggested a juvenile granulosa cell tumor (JGCT). Six cycles of bleomycin, etoposide, and carboplatin were administrated. A second surgery was applied due to relapse 4 months after the last cycle of chemotherapy, and the pathology revealed JGCT with extensive abdominopelvic seedings even after interinstitutional consultation in two hospitals. Next-generation sequencing demonstrated EWSR1 exon12-CREM exon6 fusion with neurofibromatosis-2 gene deletion, and no mutation was detected in either FOXL2 or DICER1. However, pathology consultation in two other hospitals suggested the diagnosis of OEMPNST, and additional immunohistochemical (IHC) staining revealed positive H3K27me3. Nonetheless, she was treated with nine courses of chemotherapy but experienced a second recurrence of extensive abdominal metastases approximately 3 months after ceasing chemotherapy. Neither elevated tumor makers nor abnormal sex hormones level was noted since the initial presentation. Repeated cytoreductive surgery was conducted and IHC staining showed expression of SOX10, S-100, INI-1, and α-inhibin in tumor tissue. A final diagnosis of OEMPNST with EWSR1-CREM fusion was established, indicating that the probability of OEMPNST could not be excluded when treatment for JGCT showed poor response. A comprehensive evaluation including biological characteristics, morphology, IHC staining, and molecular features is vital in the differential diagnosis between JGCT and OEMPNST.

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.

Case Report: Adjuvant image-guided radiation therapy reduces surgical invasiveness in malignant peripheral nerve sheath tumors

Introduction

Malignant peripheral nerve sheath tumors (MPNSTs) are a group of rare soft tissue sarcomas of mesenchymal origin. These tumors generally require extensive local excision owing to their aggressive potential. Though the role of radiotherapy is controversial, in this report, we present the case of an MPNST in the forearm that was treated with microsurgery followed by image-guided radiation therapy to achieve complete tumor disappearance at the 18-month follow-up.

Case report

A 69-year-old woman with underlying paranoid schizophrenia was referred to our department with pain, severe swelling, and ecchymosis of her right forearm. Physical examination showed hypoesthesia in the segments innervated by the median nerve and reduced motor strength of her right hand. A gadolinium-enhanced MRI showed a large malignant peripheral nerve sheath tumor (13 x 8 x 7 cm) of the median nerve in the forearm. She underwent microsurgical en-bloc tumor resection with sparing of the median nerve. Thirty-five days postoperatively, she underwent image-guided radiotherapy (IGRT) using volumetric modulated arc therapy (VMAT). Serial MRI scans of the forearm with Gadolinium and whole-body CT scan with contrast enhancement at 30 days, 6 months, 1 year, and 18 months postoperatively documented no tumor recurrence, remnants, or metastases.

Conclusions

In this report, we demonstrate the successful use of advanced radiotherapy techniques such as IGRT while avoiding demolitive surgery for MPNST. Though a longer follow-up is necessary, at the 18-month follow-up, the patient demonstrated good outcomes from surgical resection followed by adjuvant RT for MPNST in the forearm.

Non-squamous Laryngeal Cancer

The pathology of non-squamous carcinoma of the larynx is broad and there is a wide differential diagnosis. The most common presenting symptoms for laryngeal malignancies, both squamous and non-squamous, are hoarseness and dyspnea. Presentation with persistent or worsening symptoms and a submucosal lesion should raise suspicion for a non-squamous malignancy of the larynx. Accurate histology determines the most appropriate treatment and has an impact on prognosis.

Malignant Peripheral Nerve Sheath Tumors: Latest Concepts in Disease Pathogenesis and Clinical Management

Malignant peripheral nerve sheath tumor (MPNST) is an aggressive soft tissue sarcoma with limited therapeutic options and a poor prognosis. Although neurofibromatosis type 1 (NF1) and radiation exposure have been identified as risk factors for MPNST, the genetic and molecular mechanisms underlying MPNST pathogenesis have only lately been roughly elucidated. Plexiform neurofibroma (PN) and atypical neurofibromatous neoplasm of unknown biological potential (ANNUBP) are novel concepts of MPNST precancerous lesions, which revealed sequential mutations in MPNST development. This review summarized the current understanding of MPNST and the latest consensus from its diagnosis to treatment, with highlights on molecular biomarkers and targeted therapies. Additionally, we discussed the current challenges and prospects for MPNST management.

Results of surgical treatment of patients with malignant peripheral nerve sheath tumors: a retrospective and prospective study

Background. Peripheral nerve sheath malignancies (PNSM) are a rare and aggressive group of sarcomas that can occur sporadically, after radiation therapy, or related to neurofibromatosis type 1. Loss of function of NF1, TP53, and CDKN2A genes is thought to contribute to the progression of benign neurofibroma to PNSM and is a poor prognostic sign. The optimal management of patients with this disease is currently unresolved, and specific prognostic factors have not been established. Aim. To analyze the results of surgical treatment in patients with PNSM and establish prognostic factors of overall and recurrence-free survival rate. Materials and methods. The retrospective and prospective studies enrolled adult patients with histologically confirmed PNSM treated between 1998 and 2021 at the N.N. Blokhin National Medical Research Center for Oncology. Surgical intervention was performed on 61 patients, 38 (62%) females and 23 (38%) males. The most common PNSM localization was paravertebral (22 [36%] patients), followed by retroperitoneal (14 [23%] patients), and upper and lower extremities (13 [21%] and 12 [20%] patients, respectively). Results. For PNSM patients with a history of surgery, the median overall survival (OS) was 46 months (95% confidence interval 26.165.9). The 3-year and 5-year OS was 46% and 31%, respectively. The median recurrence-free survival (RFS) was 27 months (8.745.3), and 3-year and 5-year RFS was 26% and 13%, respectively. Median OS for grade 1 malignancies was not achieved, while grade 2 and grade 3 malignancy was 53 and 33 months, respectively (p=0.033). The median RFS for grade 1, 2, and 3 tumors was 119, 43, and 15 months, respectively (p=0.078). Patients who underwent radical (R0) surgery had higher RFS (p=0.006) and OS (p0.0001). After radical (R0) surgery, the median OS was not achieved; after nonradical (R1/R2) surgery, the median was 34 months. The median RFS was 124 months after R0-resection and 48 months after R1/R2. Conclusion. The most significant prognostic factors in PNSM patients are the radicality of the surgery performed and the malignancy grade. In our study, tumor size and localization did not affect the long-term treatment results.

Efficacy and Safety of Trametinib in Neurofibromatosis Type 1-Associated Plexiform Neurofibroma and Low-Grade Glioma: A Systematic Review and Meta-Analysis

Trametinib has been used in neurofibromatosis type 1 (NF1) patients, especially those with unresectable nerve tumors, but no systematic review based on the latest studies has been published. We conducted this meta-analysis to evaluate the effectiveness and safety of trametinib in treating NF1-related nerve tumors. Original articles reporting the efficacy and safety of trametinib in NF1 patents were identified in PubMed, EMBASE, and Web of Science up to 1 June 2022. Using R software and the 'meta' package, the objective response rates (ORRs) and disease control rates (DCRs) were calculated to evaluate the efficacy, and the pooled proportion of adverse events (AEs) was calculated. The Grading of Recommendations, Assessment, Development and Evaluation system was used to assess the quality of evidence. Eight studies involving 92 patients were included, which had a very low to moderate quality of evidence. The pooled ORR was 45.3% (95% CI: 28.9-62.1%, I2 = 0%), and the DCR was 99.8% (95% CI: 95.5-100%, I2 = 0%). The most common AEs was paronychia, with a pooled rate of 60.7% (95% CI: 48.8-72.7%, I2 = 0%). Our results indicate the satisfactory ability to stabilize tumor progression but a more limited ability to shrink tumors of trametinib in NF1-related nerve tumors. The safety profile of trametinib is satisfactory.

Epidemiology, Characteristic, and Prognostic Factors of Primary Sporadic Intradural Malignant Peripheral Nerve Sheath Tumor in the Spinal Canal: A Systematic Literature Review

Purpose

Primary sporadic intradural malignant peripheral nerve sheath tumor (MPNST) in the spinal canal is a type of rare neoplasm with challenging diagnosis and therapy. The overall prognosis of this tumor is markedly different from that of the usual spinal intradural tumors. The purpose of this systematic review is to reduce the misdiagnosis and enhance the prognosis of the disease by reviewing the literature.

Methods

PubMed, Medline, and Embase databases were searched for articles in English language published from 1980 to May 2021, yielding 500 potentially relevant articles. The keywords were as follows: “spinal”, “malignant peripheral nerve sheath tumor”, “neurosarcoma”, “malignant schwannoma”, and “malignant neurofibroma”. Thirteen papers met the eligibility criteria, including 55 cases with spinal intradural primary sporadic MPNSTs, which were confirmed by post-operation pathology. We further analyzed the clinical manifestations, radiological manifestations, pathological features, comprehensive treatment strategies, and prognosis.

Results

Fifty-five spinal intradural primary sporadic MPNSTs from 30 (54.5%) male and 25 (45.5%) female patients with an average age at diagnosis of 40 years (range, 3–70 years) were included in the study. The most common clinical manifestations were local or radicular pain and motor disturbance. All tumors had significant enhancement and heterogeneous enhancement was more common. Out of 18 lesions, 14 were diagnosed as high grade and the remaining 4 were diagnosed as low grade. The ki-67 labeling index ranged from 5% to 60%. The median recurrence and survival time were 36 and 72 months, respectively. The log-rank tests indicated that significant predictors of OS were patient age (≤30 vs. >30 years) at the time of diagnosis and the presence of metastatic disease, and similar analyses for RFS demonstrated that the presence of metastatic disease was the only significant predictor (60 vs. 10 months). The multivariate Cox proportional hazards regression analysis revealed that absence of metastasis was an independent factor for predicting a favorable prognosis.

Conclusions

Spinal intradural primary sporadic MPNSTs are challenging malignant tumors without a systematic treatment plan. The factors affecting its prognosis are not clear. Even after surgical treatment and adjuvant treatment, the recurrence rate and mortality rate are still high. Clinicians should be alert to the possibility of this disease and achieve early detection and treatment.

Clinical Outcome After Pencil Beam Scanning Proton Therapy of Patients With Non-Metastatic Malignant and Benign Peripheral Nerve Sheath Tumors

Objective

Peripheral nerve sheath tumors (PNSTs) commonly arise from peripheral nerve roots and grow locally invasive. Malignant PNSTs (mPNSTs) represent aggressive sarcomas of neural origin that can originate from PNSTs. Radiation therapy is commonly used as part of the required multimodal treatment. However, both entities tend to occur early in life and are associated with the genetic disorder neurofibromatosis type 1 (NF-1), which is known to cause increased radiosensitivity. Pencil beam scanning proton therapy (PBSPT) allows for a minimization of the dose delivered to organs at risk and the integral dose and, thus, potentially also a reduction of radiation-induced adverse events. We report the clinical outcome and toxicity rates of patients with (m)PNSTs treated with PBSPT.

Methods

We retrospectively reviewed 36 patients who received PBSPT (median dose, 64 GyRBE) with curative intent for (m)PNSTs between 1999 and 2020 at our institute. Twenty-eight (78%) and 8 (22%) patients were treated at diagnosis and for tumor recurrence/progression, respectively. The median age was 32 years (range, 3–75), and 25 (69%) patients were male. mPNST and PNST were diagnosed in 31 (86%) and 5 (14%) patients, respectively. Underlying NF-1 disease was found in 8 (22%) patients. Acute and late toxicities were recorded according to Common Terminology Criteria for Adverse Events, version 4.1 (CTCAE v4.1). Overall survival (OS), local control (LC), and distant control (DC) were estimated using the Kaplan–Meier method.

Results

With a median follow-up time of 31 months (range, 4–194), 13 (36%) patients died from a progressive disease, 8 (22%) experienced local failure, and 14 (39%) experienced distant failure after PBSPT. Estimated 2-year OS, LC, and DC were 75.5%, 73.5%, and 61.2%, respectively. Acute grade 3 toxicity (dermatitis, mucositis, and pain) was observed in 5 (14%) patients. Late grade 3 cataract and osteonecrosis were both observed in 1 (3%) patient at 34 and 194 months after PBSPT, respectively. There was no late grade >3 toxicity or radiation-induced secondary cancer.

Conclusion

To our knowledge, this is the first study to analyze the outcome of (m)PNSTs treated with proton therapy using a PBS delivery paradigm. In our cohort, consisting mainly of patients with mPNSTs, we report reasonable oncological outcomes and low toxicity rates after PBSPT.

Clinical and Pathologic Characterization of 94 Radiation-Associated Sarcomas: Our Institutional Experience

Radiation-associated sarcomas are an uncommon complication of therapeutic radiation. However, their prevalence has increased with the more widespread use of this treatment modality. The clinical, pathologic and genetic characteristics of radiation-associated sarcomas are not fully understood. In this study we describe the features of 94 radiation-associated sarcomas reviewed at our institution between 1993 and 2018, evaluate their overall survival (OS) and progression-free survival (PFS) outcomes, and compare them with their sporadic counterparts reviewed within the same time period. Histologic subtypes of all radiation-associated sarcomas included 31 (33%) undifferentiated sarcomas, 20 (21%) osteosarcomas, 17 (18%) angiosarcomas, 10 (11%) malignant peripheral nerve sheath tumor (MPNST), 9 (10%) leiomyosarcomas, 4 (4%) myxofibrosarcomas, and 3 (3%) rhabdomyosarcomas. Six patients had a documented cancer predisposition syndrome. The most common preceding neoplasms included adenocarcinoma (47%) and squamous cell carcinoma (19%), with a mean latency of 13 years. Multivariable Cox survival analysis demonstrated that advanced stage at diagnosis based on pT category (AJCC eighth edition) and fragmented resection were associated with worse survival outcomes. In addition, there was a statistically significant difference in PFS between radiation-associated undifferentiated sarcomas and MPNST when compared to their sporadic counterparts using the Kaplan-Meier method and Log-rank analysis. Overall, our study shows that radiation-associated sarcomas comprise a wide clinico-pathologic spectrum of disease, with a tendency for aggressive clinical behavior. This study further delineates the understanding of these uncommon diseases. Future studies are necessary to better understand the genetic and epigenetic changes that drive the differences in behavior between these tumors and their sporadic counterparts, and to offer better treatment options.

Morbidity and Function Loss After Resection of Malignant Peripheral Nerve Sheath Tumors

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft tissue sarcomas. Their resection may lead to serious morbidity. Incidence of postoperative motor and sensory deficits is unknown, and reconstruction aimed at restoring such deficits is infrequently carried out.

OBJECTIVE

To identify the incidence and risk factors of postoperative morbidity in MPNST as well as the use and outcomes of functional reconstructions in these patients.

METHODS

Postoperative function and treatment of MPNSTs diagnosed from 1988 to 2019 in 10 cancer centers was obtained. Two models were constructed evaluating factors independently associated with postoperative motor (<M3) or critical sensory loss. Critical sensation was defined as partial or complete loss of hand, foot, or buttocks sensation.

RESULTS

A total of 756 patients (33.4% neurofibromatosis type 1, NF1) were included. MPNSTs originated in 34.4% from a major nerve. Of 658 surgically treated patients, 27.2% had <M3 muscle power and 24.3% critical sensory loss. Amputations were carried out in 61 patients. Independent risk factors for motor and sensory loss included patients with NF1, symptomatic, deep-seated, extremity, or plexus tumors originating from major nerves (all P < .05). A total of 26 patients underwent functional reconstructions. The majority (64%) of these patients regained at least M3 muscle power and 33% M4 despite 86% receiving multimodal therapy.

CONCLUSION

Resection of MPNSTs commonly results in motor and sensory deficits. Patients with NF1, symptomatic, deep-seated tumors, arising from major nerves were associated with a higher risk for developing postoperative morbidity. Functional reconstructions are infrequently performed but can improve functional outcomes.

Malignant Peripheral Nerve Sheath Tumors-A Comprehensive Review of Pathophysiology, Diagnosis, and Multidisciplinary Management

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft tissue sarcomas (STS) with nerve sheath differentiation and a tendency to metastasize. Although occurring at an incidence of 0.001% in the general population, they are relatively common in individuals with neurofibromatosis type 1 (NF1), for whom the lifetime risk approaches 10%. The staging of MPNSTs is complicated and requires close multi-disciplinary collaboration. Their primary management is most often surgical in nature, with non-surgical modalities playing a supportive, necessary role, particularly in metastatic, invasive, or widespread disease. We, therefore, sought to provide a comprehensive review of the relevant literature describing the characteristics of these tumors, their pathophysiology and risk factors, their diagnosis, and their multi-disciplinary treatment. A close partnership between surgical and medical oncologists is therefore necessary. Advances in the molecular characterization of these tumors have also begun to allow the integration of targeted RAS/RAF/MEK/ERK pathway inhibitors into MPNST management.

The clinical course and role of surgery in pediatric malignant peripheral nerve sheath tumors: a database study

OBJECTIVE

Malignant peripheral nerve sheath tumors (MPNSTs) are rare tumors found throughout the body, with their clinical course in children still not completely understood. Correspondingly, this study aimed to determine survival outcomes and specific clinical predictors of survival in this population from a large national database.

METHODS

All patients with MPNSTs aged ≤ 18 years in the US National Cancer Database (NCDB) between 2005 and 2016 were retrospectively reviewed. Data were summarized, and overall survival was modeled using Kaplan-Meier and Cox regression analyses.

RESULTS

A total of 251 pediatric patients with MPNSTs (132 [53%] females and 119 [47%] males) were identified; the mean age at diagnosis was 13.1 years (range 1-18 years). There were 84 (33%) MPNSTs located in the extremities, 127 (51%) were smaller than 1 cm, and 22 (9%) had metastasis at the time of diagnosis. In terms of treatment, surgery was pursued in 187 patients (74%), chemotherapy in 116 patients (46%), and radiation therapy in 129 patients (61%). The 5-year overall survival rate was estimated at 52% (95% CI 45%-59%), with a median survival of 64 months (range 36-136 months). Multivariate regression revealed that older age (HR 1.10, p < 0.01), metastases at the time of diagnosis (HR 2.14, p = 0.01), and undergoing biopsy only (HR 2.98, p < 0.01) significantly and independently predicted a shorter overall survival. Chemotherapy and radiation therapy were not statistically significant.

CONCLUSIONS

In this study, the authors found that older patient age, tumor metastases at the time of diagnosis, and undergoing only biopsy significantly and independently predicted poorer outcomes. Only approximately half of patients survived to 5 years. These results have shown a clear survival benefit in pursuing maximal safe resection in pediatric patients with MPNSTs. As such, judicious workup with meticulous resection by an expert team should be considered the standard of care for these tumors in children.

Fédération Nationale Des Centres de Lutte Contre Le Cancer (FNCLCC) Grading, Margin Status and Tumor Location Associate With Survival Outcomes in Malignant Peripheral Nerve Sheath Tumors

BACKGROUND

Histologic grading using the Fédération Nationale des Centres de Lutte Contre Le Cancer (FNCLCC) system is not universally accepted as applicable to malignant peripheral nerve sheath tumor (MPNST), as its prognostic value is not well established.

METHODS

We retrospectively evaluated 99 cases of MPNST to investigate any association between the outcomes overall survival (OS) and progression-free survival (PFS), and predictor variables FNCLCC grade, clinical setting, tumor location, and tumor size at diagnosis using multivariable Cox proportional hazard analysis.

RESULTS

Univariable and multivariable analysis demonstrate a statistically significant association between FNCLCC grade and both OS and PFS when comparing tumors by histologic grade. Of note, no deaths were observed in patients with grade 1 MPNST. Other variables associated with unfavorable outcomes include fragmented resection and primary site, with tumors in the extremities having favorable OS, but not PFS, when compared with those in truncal locations. Tumors in the head and neck had favorable PFS, but not OS, compared with those in the trunk. No statistically significant differences in OS or PFS were observed when comparing patient age and sex, tumor size at diagnosis, clinical setting (primary vs. type-1 neurofibromatosis vs. radiation associated) or history of neoadjuvant therapy. Interobserver agreement for FNCLCC grading of these tumors was considered good (S*=0.77, 95% confidence interval: 0.71-0.84).

CONCLUSIONS

Association between FNCLCC grading and survival outcomes in MPNST suggests potential value to routinely grading these neoplasms. However, the subjectivity of the grading system, particularly when assigning a tumor differentiation score, may pose a challenge, especially in low and intermediate grade lesions.

Cranial nerve and intramedullary spinal malignant peripheral nerve sheath tumor associated with neurofibromatosis-1

Background:

Malignant peripheral nerve sheath tumors (MPNSTs) are uncommon but aggressive neoplasms associated with radiation exposure and neurofibromatosis Type I (NF1). Their incidence is low compared to other nervous system cancers, and intramedullary spinal lesions are exceedingly rare. Only a few case reports have described intramedullary spinal cord MPNST.

Case Description:

We describe the clinical findings, management, and outcome of a young patient with NF1 who developed aggressive cranial nerve and spinal MPNST tumors. This 35-year-old patient had familial NF1 and a history of optic glioma treated with radiation therapy (RT). She developed a trigeminal MPNST that was resected and treated with RT. Four years later, she developed bilateral lower extremity deficits related to an intramedullary cervical spine tumor, treated surgically, and found to be a second MPNST.

Conclusion:

To the best of our knowledge, this is the first report of cranial nerve and intramedullary spinal MPNSTs manifesting in a single patient, and only the third report of a confined intramedullary spinal MPNST. This unusual case is discussed in the context of a contemporary literature review.

Clinical Outcomes and Prognostic Factors for Patients with Malignant Peripheral Nerve Sheath Tumour

Introduction

Few studies have described the characteristics and prognostic factors of patients with malignant peripheral nerve sheath tumour (MPNST). In this study, we retrospectively investigated the clinicopathological features, clinical outcomes, and prognostic factors of these patients. Patients and Methods. We recruited patients with MPNST who were treated at our institutions from 1991 to 2020. We collected and statistically analysed information on patient-, tumour-, and treatment-related factors. The median follow-up period was 61 months (range, 1-335.8 months).

Results

A total of 60 patients (31 males, 29 females) with a median age of 55 years (range, 8-84 years) at initial diagnosis were included. The median tumour size was 7 cm (range, 1.6-30 cm) in the greatest dimension. The 5-year overall survival (OS) rate of all patients was 69.5%. Univariate analysis revealed that large-sized tumour, metastasis at diagnosis, and no surgery of the primary tumour were significantly associated with patients with worse OS. Multivariate analysis identified surgery of the primary tumour as an independent prognostic factor for improved OS. Among patients with localised disease at diagnosis who underwent surgery of the primary tumour at our institutions, the 5-year OS, local recurrence-free survival (LRFS), and metastasis-free survival (MFS) rates were 81.1%, 78.2%, and 70.3%, respectively. Univariate analysis revealed that positive surgical margin was significantly correlated with unfavourable OS and LRFS, and high grade was a poor prognostic indicator for MFS.

Conclusion

Complete surgical resection with negative surgical margins is necessary for a successful MPNST treatment. Multidisciplinary management of MPNST with aggressive features is important for optimising patient outcomes.

Pseudoprogression of Malignant Peripheral Nerve Sheath Tumor in Patient with Neurofibromatosis Type 1, a Case Report

Pseudoprogression, defined as the radiographic false appearance of disease progression, is not frequently observed in patients with malignant peripheral nerve sheath tumor (MPNST). We report on a case of a patient with neurofibromatosis type 1 (NF1) MPNST pseudoprogression that presented as suspected local recurrence 9.5 years after last treatment. The patient underwent surgical resection following growth of a mass on sequential MRI imaging; surgical pathology, however, showed skeletal muscle with atrophy, fibroadipose tissue, and fat necrosis, without any evidence of tumor. As MPNST survival rates increase, physicians should consider pseudoprogression as a potential presentation after prior treatment.

The Association of Metastasis Pattern and Management of Metastatic Disease with Oncological Outcomes in Patients with Malignant Peripheral Nerve Sheath Tumors: A Multicenter Cohort Study

Simple Summary

Around 40% of patients with MPNSTs develop distant metastasis (DM) within five years. Identification of MPNST patients more likely to develop DM and the identification of prognostic factors after DM diagnosis may guide clinical decision-making and may result in a better balance between quantity and quality of life. This study aimed to identify clinicopathologic and treatment-related factors associated with the development of DM and with overall survival (OS) after DM diagnosis. NF1, high grade, tumor size, triton and R2 resections were independent risk factors for the development of DM. This is the first study that reveals that NF1 status is also independently associated with worse survival after DM diagnosis with a median survival difference of more than 6 months between NF1 and no-NF1 patients.

Abstract

Purpose: This multicenter cohort study aimed to identify clinicopathologic and treatment-related factors associated with the development of distant metastasis (DM) and with overall survival (OS) after DM diagnosis in patients with malignant peripheral nerve sheath tumors (MPNST). Methods: All patients diagnosed with primary MPNST from 1988 to 2019 who were surgically treated for the primary tumor were included. Multivariable Cox regression analyses were performed to identify factors associated with DM and OS after DM diagnosis. Results: A total of 383 patients were included in this analysis, of which 150 developed metastatic disease. No differences in clinicopathologic characteristics and clinical outcome were found between patients with synchronous and metachronous DM. Neurofibromatosis type 1 (NF1), high grade, tumor size, triton and R2 resections were independent risk factors for the development of DM. NF1 and more than two metastasis sites were independently associated with worse OS after DM diagnosis. Metastasectomy, chemotherapy and the metastatic site category ‘other’ were associated with prolonged survival after DM diagnosis. Conclusions: This analysis provides important insights into clinicopathologic and treatment factors associated with outcomes in metastatic MPNST. Moreover, NF1-status is associated with a higher risk of DM; it is also independently associated with worse survival in metastatic MPNST.

Intracranial Malignant Peripheral Nerve Sheath Tumors Not Associated with a Cranial Nerve: Systematic Review and Illustrative Case

OBJECTIVE

Primary intracranial malignant peripheral nerve sheath tumors (MPNSTs) not associated with cranial nerves are rare and aggressive neoplasms. The rarity of presentation has precluded rigorous analysis of diagnosis, risk factors, treatment, and survival. We analyzed every reported case through exhaustive literature review. In addition, we present our own experience managed with resection, radiotherapy, and first use of targeted therapy in a tumor of this type for a BRAF mutation identified during next-generation sequencing.

METHODS

Two databases, PubMed and Embase, and crossed references were queried for intracranial MPNSTs not associated with a cranial nerve. Extracted variables included demographics, risk factors, tumor characteristics, interventions, and outcomes. Univariate and multivariate analysis was performed to identify factors with survival benefit.

RESULTS

A total of 56 patients (including the present case) were included from 743 literature results. There was a male/female ratio of 1.5:1 and mean diagnosis age of 29.7 ± 21.8 years. Seventy-one percent of cases were sporadic and 23% neurofibromatosis type 1 related. Median survival was 29 ± 22.1 months with 1-year survival of 60%. Factors associated on univariate analysis with reduced survival were subtotal resection (P = 0.05), older age (P = 0.023), triton histology (P < 0.001), and early recurrence (≤6 months) (P = 0.018). On multivariate analysis, gross total resection reduced mortality risk (P = 0.011), whereas triton histology (P = 0.017) and infratentorial tumor location (P = 0.037) increased mortality.

CONCLUSIONS

We present a systematic review of intracranial MPNSTs not associated with a cranial nerve. These tumors have poor prognosis and benefit from aggressive resection, multimodal treatment, and close follow-up. Next-generation sequencing can show molecular alterations for potential targeted therapy.

Surgical Management of Symptomatic Lumbar, Sacral, and Lumbosacral Plexus Tumors: a Peripheral Nerve Unit Experience

OBJECTIVE

Data concerning the surgical treatment of lumbosacral plexus tumors (LSPTs) is scarce. This study aims to present our experience with a series of 19 patients surgically treated for symptomatic LSPTs at our institution.

METHODS

This is a retrospective study of 19 patients surgically treated for symptomatic LSPTs from 2011 to 2019. Clinical data were retrieved from medical records and consisted of age, gender, clinical presentation, location of the lesion, surgical approach, final histopathologic diagnosis, follow-up time, outcomes, and complications.

RESULTS

Nineteen surgical procedures were conducted. Thirteen patients were female and six, male. The median age of patients was 45 years (range 20 to 63 years). No patients harbored genetic syndromes. Surgical treatment appears to be correlated to the reduction of pain in patients with peripheral nerve sheath tumors (PNSTs), as assessed by visual analog scale (VAS). Sixteen patients did not present with new-onset deficits during follow-up (84.2%), two of whom recovered from their preoperative deficit. Four patients presented with postoperative weakness. The histopathological diagnoses were 11 schwannomas, four neurofibromas, three metastases, and one lymphoma.

CONCLUSIONS

LSPTs are rare. When surgical treatment is indicated, it usually requires multidisciplinary management. Surgery appears to be effective concerning the reduction of pain in PNSTs and may also recover neurological deficits. Iatrogenic neurological deficits are an evident risk, such that intraoperative multimodal monitoring should always be performed if available. In lesions involving the sacral plexus, we found it to be indispensable.

Case report of a man with multiple paragangliomas and pathogenic germline variants in both NF1 and SDHD

We report a novel case of multiple paragangliomas in a patient who was identified with pathogenic variants in both NF1 and SDHD genes. The proband is a man with known familial NF1 disease, diagnosed clinically in childhood. Multiple head and neck paragangliomas (HNPGL) were found during investigations for acute left sided neurological symptoms, in the region of his known plexiform neurofibroma. He was referred for genetic counselling. He underwent surgery to remove a left carotid body tumor (CBT). A pheochromocytoma and paraganglioma gene panel was tested. Blood and HNPGL tumor DNA were analyzed by whole exome sequencing. In addition to the NF1 truncating variant c.5107delA, p.(Ser1703AlafsTer7), the SDHD truncating pathogenic variant c.3G > A, p.(Met1?) was found. Tumor sequencing showed no LOH of SDHD or NF1, but monoallelic loss of 11p15 and 11q12.2-q12.3 was observed. Co-occurrence of pathogenic variants in multiple cancer susceptibility genes is rare but possible, identified by the increased use of panel testing. This is the first description of a patient presenting with NF1 and SDHD dual pathology, with HNPGL development due to SDHD. This case illustrates the central role of genetic sequencing in PPGLs and the strong genotype-phenotype correlations of different genes.

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.

Protein Tyrosine Phosphatase Receptor S Acts as a Metastatic Suppressor in Malignant Peripheral Nerve Sheath Tumor via Profilin 1-Induced Epithelial-Mesenchymal Transition

Malignant peripheral nerve sheath tumors (MPNST) are aggressive sarcomas with over half of cases developed in the context of neurofibromatosis type 1. Surgical resection is the only effective therapy for MPNST. The prognosis is very dismal once recurrence or metastasis occurs. Epithelial-mesenchymal transition (EMT) is a key process of recurrence and metastasis involving reorganizations of the actin cytoskeleton and actin-binding proteins (ABP) play a non-negligible role. Protein tyrosine phosphatase receptor S (PTPRS), a tumor suppressor previously reported in colorectal cancer, hepatocellular carcinoma and head and neck cancer, is thought to mediate cell migration and invasion by downregulation of EMT. However, its role in MPNST remains unknown. In the present study, by using tissue microarray we demonstrated low expression of PTPRS was related to poor prognosis in MPNST. Knockdown of PTPRS in MPNST cell lines increased migration/invasion and EMT processes were induced with increased N-cadherin and decreased E-cadherin, which indicated PTPRS may serve as a tumor suppressor in MPNST. In addition, we tested all EMT related ABP and found profilin 1 was significantly elevated in PTPRS downregulated MPNST cell lines. As a member of actin-binding proteins, profilins are regulators of actin polymerization and contribute to cell motility and invasion, which have been reported to be responsible for EMT. Moreover, results showed that downregulation of profilin 1 could restore the EMT processes caused by PTPRS downregulation in vitro and in vivo. Furthermore, high expression of profilin 1 was significantly associated with dismal prognosis. These results highlighted PTPRS served as a potential tumor suppressor in the recurrence and metastasis of MPNST via profilin 1 induced EMT processes and it might provide potential targets for future clinical therapeutics.

Genetic basis of neurofibromatosis type 1 and related conditions, including mosaicism

INTRODUCTION

Neurofibromatosis type 1 (NF1) is a frequent autosomal dominant disorder characterised by café-au-lait maculae (CALM), skinfold freckling, iris Lisch nodules and benign peripheral nerve sheath tumours (neurofibromas).

MECHANISM

The NF1 gene is a tumour suppressor gene and NF1 individuals have an increased risk for a long list of tumours, all resulting from a second hit in the normal copy of the NF1 gene. Remarkably, some non-tumour phenotypes such as CALM and pseudarthrosis are also caused by a "second hit". Germline mutations inactivating the NF1 gene show a large variability in genetic mechanisms ranging from single-nucleotide substitutions and somatic mosaicism to large deletions affecting neighbouring genes. Molecular confirmation of the clinical diagnosis is becoming increasingly more important to differentiate NF1 from other syndromes such as Legius syndrome, to investigate genotype-phenotype correlations relevant in 10% of cases and to detect somatic mosaicism.

SURVEILLANCE AND THERAPY

Some degree of learning difficulties, attention deficit and social problems are observed in most children and affect quality of life. There is a large individual variability in complications and the evolution of the disease is difficult to predict. Specialised outpatient clinics for children have been widely established and are important for surveillance and guidance. Regular surveillance is also important for adolescents and adults because many tumour complications can be detected by whole-body MRI and treated even before symptoms develop and irreversible damage occurs. Recent data on nodular plexiform neurofibromas with continued growth in adolescents and young adults show that many of these tumours are premalignant lesions called atypical neurofibromatous neoplasm of uncertain biological potential (ANNUBP). Specific surveillance and timely local resection of these benign peripheral nerve sheath tumours might be important to prevent malignant degeneration. In the last years, targeted therapy with MEK inhibitors has shown promise to treat unresectable and symptomatic plexiform neurofibromas. Many more challenges remain to find the best way to monitor children and adults for potential complications and to find a satisfying cure for many complications in this disorder.

Prognosis and risk factors for malignant peripheral nerve sheath tumor: a systematic review and meta-analysis

Background

No available meta-analysis was printed to systematically introduce the MPNST clinic outcome and risk factors based on largely pooled data. This systematic review and meta-analysis aimed to investigate 5-year OS rate, 5-year EFS rate, and LR rate for MPNST, and to assess potential risk factors for prognosis.

Methods

Electronic articles published between January 1, 1966 and February 29, 2020 were searched and critically evaluated. The authors independently reviewed the abstracts and extracted data for 5-year OS rate, 5-year EFS rate, LR rate, and potential risk factors for prognosis.

Results

Twenty-eight literatures were finally included for meta-analysis. The pooled 5-year OS rate, 5-year EFS rate, and LR rate were 49%, 37%, and 38%, respectively. The significant prognostic factors for survival were NF1 status, tumor size, depth, location, malignant grade, margin status, chemotherapy, and radiotherapy. Age and sex were not associated with survival.

Conclusion

Survival and local recurrence of MPNST are poor. Worse prognosis is mainly associated with NF 1, large size, deep to fascia, high grade, metastases, and location (trunk and head and neck). Complete resection with adequate surgical margins is the mainstay protective factor of MPNST patients, following necessary adjuvant therapies.

Malignant peripheral nerve sheath tumors - Outcomes and prognostic factors based on the reference center experience

INTRODUCTION

Malignant peripheral nerve sheath tumor (MPNST) accounts for about 5% of soft tissue sarcomas. It can occur as sporadic diseases or can be associated with type 1 neurofibromatosis. MPNST is usually associated with poor prognosis, mostly due to their aggressive behavior, high metastatic potential, and resistance to chemotherapy. Our study aimed to determine treatment outcomes and associated prognostic factors in a large cohort of patients with MPNSTs treated at the reference sarcoma center.

METHODS

239 consecutive patients (114 women and 125 men) diagnosed with MPNST between March 1998 and March 2018 who were treated with surgery with curative intent in the reference sarcoma center were included in the retrospective analysis.

RESULTS

The mean age at diagnosis was 51 years (range 15-86). 28 (11.7%) patients had neurofibromatosis type 1 associated tumors (NF1 positive). Median OS was 126.5 months and 5-year survival rate was 61.9% in the group treated with curative intent. Median DFS, LRFS and DMFS were 91.6, 126.5 and 126.5 months, respectively. We identified tumor size, high tumor grade and positive surgical margins as independent negative predictors of DFS, LRFS, DMFS and OS.

CONCLUSIONS

High-quality surgery remains a gold standard of MPNST treatment. High grade, size and quality of surgery are significant independent prognostic factors for overall survival. There is an unmet need for improvement, especially regarding the perioperative treatment and treatment of metastatic disease. Future studies on the biology of MPNST would lead to the development of novel treatment options and improvement of treatment outcomes.

Malignant peripheral nerve sheath tumors in children, adolescents, and young adults: Treatment results of five Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry

BACKGROUND AND OBJECTIVES

Malignant peripheral nerve sheath tumors (MPNST) are aggressive soft tissue sarcomas that present as large, invasive tumors. Our aim was to assess outcomes, identify prognostic factors, and analyze treatment strategies in a prospectively collected pediatric cohort.

METHODS

Patients less than 21 years with MPNST treated in the consecutive prospective European Cooperative Weichteilsarkom Studiengruppe (CWS)-trials (1981-2009) and the CWS-SoTiSaR registry (2009-2015) were analyzed.

RESULTS

A total of 159 patients were analyzed. Neurofibromatosis type I (NF1) was reported in thirty-eight patients (24%). Most were adolescents (67%) with large (>10 cm, 65%) tumors located at extremities (42%). Nodal involvement was documented in 15 (9%) and distant metastases in 15 (9%) upon diagnosis. Overall, event-free survival (EFS) was 40.5% at 5 and 36.3% at 10 years, and overall survival (OS) was 54.6% at 5 and 47.1% at 10 years. Age, NF1 status, tumor site, tumor size, Intergroup Rhabdomyosarcoma Study (IRS) group, metastatic disease, and achieving first complete remission (CR1) were identified as prognostic factors for EFS and/or OS in the univariate analysis.

CONCLUSIONS

Prognostic factors were identified and research questions for future clinical trials were addressed.

Incidence of second malignancies in individuals diagnosed with malignant peripheral nerve sheath tumors

BACKGROUND

The incidence of malignant peripheral nerve sheath tumors (MPNSTs) is low in the general population, although individuals with Neurofibromatosis Type I (NF1) are particularly susceptible. These tumors generally have a high probability of metastasis. The rate and types of second malignancies (SMNs) after a primary diagnosis of MPNST are not well characterized. We aimed to quantify the rate of SMNs among individuals with a first primary MPNST using population-based data.

METHODS

We estimated age-standardized incidence rates (SIRs) for SMNs among 1,579 primary MPNST cases between ages 0-85+ using SEER 18 (2000-2015). We estimated incidence rate ratios (IRRs) and 95% confidence intervals (95% CI) for SMNs in MPNST cases compared with general population rates. We conducted sex-stratified and age-restricted analyses (< 30 years at diagnosis).

RESULTS

Seven percent (108/1579) of MPNST cases developed a SMN (SIR of 4635 cases/million). Compared to the general population, MPNST cases were more likely to develop SMNs (IRR: 29.3; 95% CI 23.8-34.8) and had a much higher rate of second MPNSTs (IRR: 15,992.9; 95% CI 9594.5-22,391.3). Aside from a second MPNST, second cancers were frequently diagnosed in the breast, lung, skin, and soft tissue in females and were myeloid and skin malignancies in males. When restricted to < 30 years of age, second MPNSTs were the most common cancers diagnosed.

CONCLUSIONS

The rate of SMNs among MPNST cases is tremendously higher than that observed among individuals with other cancers, particularly for second MPNSTs. These findings suggest rates of SMNs may also be higher in NF1 individuals.

Neurofibromatosis-associated malignant peripheral nerve sheath tumors in children have a worse prognosis: A nationwide cohort study

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNST) are rare and aggressive non-rhabdomyoblastic soft-tissue sarcomas (NRSTS) in children. This study set out to investigate clinical presentation, treatment modalities, and factors associated with survival in pediatric MPNST using Dutch nationwide databases.

METHODS

Data were obtained from the Netherlands Cancer Registry (NCR) and the Dutch Pathology Database (PALGA) from 1989 to 2017. All primary MPNSTs were collected. Demographic differences were analyzed between adult and pediatric (age ≤18 years) MPNST. In children, demographic and treatment differences between neurofibromatosis type 1 (NF1) and non-NF1 were analyzed. A Cox proportional hazard model was constructed for localized pediatric MPNSTs.

RESULTS

A total of 70/784 MPNST patients were children (37.1% NF1). Children did not present differently from adults. In NF1 children, tumor size was more commonly large (> 5 cm, 92.3% vs 59.1%). Localized disease was primarily resected in 90.6%, and radiotherapy was administered in 37.5%. Non-NF1 children tended to receive chemotherapy more commonly (39.5% vs 26.9%). Overall, estimated five-year survival rates of localized NF1-MPNST was 52.4% (SE: 10.1%) compared with 75.8% (SE: 7.1%) in non-NF1 patients. The multivariate model showed worse survival in NF1 patients (HR: 2.98; 95% CI, 1.17-7.60, P = 0.02) and increased survival in patients diagnosed after 2005 (HR: 0.20; 95% CI, 0.06-0.69, P = 0.01). No treatment factors were independently associated with survival.

CONCLUSION

Pediatric MPNSTs have presentations similar to adult MPNSTs. In children, NF1 patients present with larger tumors, but are treated similarly to non-NF1 MPNSTs. In localized pediatric MPNST, NF1 is associated with worse survival. Promisingly, survival has increased for pediatric MPNSTs after 2005.

Oncological Treatment Considerations Differ across Surgical Subspecialties Treating Malignant Peripheral Nerve Sheath Tumors: An International Survey

Background

Malignant peripheral nerve sheath tumors (MPNSTs) are rare and aggressive soft tissue sarcomas (STS) that, because of their origin, are operated by several surgical subspecialties. This may cause differences in oncologic treatment recommendations based on presentation. This study investigated these differences both within and between subspecialties.

Methods

A survey was distributed among several (inter)national surgical societies. Differences within and between subspecialties were analyzed by χ²-tests.

Results

In total, 30 surgical oncologists, 30 neurosurgeons, 85 plastic surgeons, and 29 “others” filled out the survey. Annual caseload, tumor sites operated, and fellowship training differed significantly between subspecialties. While most surgeons agreed upon preoperative use of MRI, the use of radiological staging and FDG-PET use differed between subspecialties. Surgical oncologists agreed upon core needle biopsies as an ideal type of biopsy while other subspecialties differed in opinion. On average, 53% of surgeons always consider preservation of function preoperatively, but 42% would never perform less extensive resections for function preservation. Respondents agreed that radiotherapy should be considered in tumor sizes >10 cm, microscopic, and macroscopic positive margins. A preferred sequence of radiotherapy administration differed between subspecialties. There was no consensus on indications and sequence of administration of chemotherapy in localized disease.

Conclusion

Surgical oncologists generally agree on preoperative diagnostics; other subspecialties do not. Considering the preservation of function differed among all subspecialties. Surgeons do agree on some indications for radiotherapy, yet the use of chemotherapy in localized MPNSTs lacks consensus. A preferred sequence of multimodal therapy differs between and within surgical subspecialties, but surgical oncologists prefer neoadjuvant radiotherapy.

Sellar surprises: a single-centre experience of unusual sellar masses

BACKGROUND

Most common incidentally detected sellar-suprasellar region (SSR) masses are pituitary adenomas, followed by craniopharyngioma, rathke's cleft cyst, hypophysitis, and meningioma. Besides these, certain unusual SSR lesions can sometimes present as diagnostic challenges, where diagnosis is often made post-operatively on histopathology, the pre-operative suspicion of which might have influenced the management strategies. Series describing such masses are few.

OBJECTIVE

To present clinical, biochemical, and radiological characteristics and management outcomes of rare SSR lesions other than pituitary adenomas, craniopharyngioma, rathke's cleft cyst, hypophysitis, and meningioma.

DESIGN, SETTING, PATIENTS

Retrospective case record analysis of patients with uncommon SSR masses (from January 2006 to December 2016).

RESULTS

Our series consisted of ten patients, five with neoplastic and five with non-neoplastic lesions. Neoplastic masses included granular cell tumor (n = 2), astrocytoma (n = 1), malignant peripheral nerve sheath tumor (MPNST, n = 1), and metastasis from occult papillary carcinoma of thyroid (n = 1), while non-neoplastic masses were aspergillus abscess (n = 1), sterile abscess (n = 1), and tubercular abscess (n = 1), aneurysm of left internal carotid artery (n = 1), and ruptured dermoid cyst (n = 1). All patients (except one) presented with headache and/or visual disturbance. Only one patient had acromegaly while most others had hypopituitarism. We describe detailed MRI characteristics of each of the lesion. Seven patients underwent trans-sphenoidal surgery. Post-operatively, five patients had permanent diabetes insipidus, while two patients died in early post-operative period.

CONCLUSION

Our series expand the differential diagnostic considerations of SSR lesions. Most of the rare SSR masses present with symptoms of mass effects and hypopituitarism. Except for some non-neoplastic lesions like sellar abscesses, aneurysms, and dermoid cysts which can have some specific imaging characteristics that can provide clue to pre-operative diagnosis, most of the other neoplastic masses have overlapping radiological features, and pre-operative suspicion remains difficult.

Treatment of malignant peripheral nerve sheath tumors in pediatric NF1 disease

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) are rare yet highly aggressive soft tissue sarcomas. Children with neurofibromatosis type 1 (NF1) have a 10% lifetime risk for development of MPNST. Prognosis remains poor and survival seems worse for NF1 patients.

METHODS

This narrative review highlights current practices and pitfalls in the management of MPNST in pediatric NF1 patients.

RESULTS

Preoperative diagnostics can be challenging, but PET scans have shown to be useful tools. More recently, functional MRI holds promise as well. Surgery remains the mainstay treatment for these patients, but careful planning is needed to minimize postoperative morbidity. Functional reconstructions can play a role in improving functional status. Radiotherapy can be administered to enhance local control in selected cases, but care should be taken to minimize radiation effects as well as reduce the risk of secondary malignancies. The exact role of chemotherapy has yet to be determined. Reports on the efficacy of chemotherapy vary as some report lower effects in NF1 populations. Promisingly, survival seems to ameliorate in the last few decades and response rates of chemotherapy may increase in NF1 populations when administering it as part of standard of care. However, in metastasized disease, response rates remain poor. New systemic therapies are therefore desperately warranted and multiple trials are currently investigating the role of drugs. Targeted drugs are nevertheless not yet included in first line treatment.

CONCLUSION

Both research and clinical efforts benefit from multidisciplinary approaches with international collaborations in this rare malignancy.

A nationwide cohort study on treatment and survival in patients with malignant peripheral nerve sheath tumours

BACKGROUND

Despite curative intents of treatment in localized malignant peripheral nerve sheath tumours (MPNSTs), prognosis remains poor. This study investigated survival and prognostic factors for overall survival in non-retroperitoneal and retroperitoneal MPNSTs in the Netherlands.

METHODS

Data were obtained from the Netherlands Cancer Registry and the Dutch Pathology Database. All primary MPNSTs were collected. Paediatric cases (age ≤18 years) and synchronous metastases were excluded from analyses. Separate Cox proportional hazard models were made for retroperitoneal and non-retroperitoneal MPNSTs.

RESULTS

A total of 629 localized adult MPNSTs (35 retroperitoneal cases, 5.5%) were included for analysis. In surgically resected patients (88.1%), radiotherapy and chemotherapy were administered in 44.2% and 6.7%, respectively. In retroperitoneal cases, significantly less radiotherapy and more chemotherapy were applied. In non-retroperitoneal MPNSTs, older age (60+), presence of NF1, size >5 cm, and deep-seated tumours were independently associated with worse survival. In retroperitoneal MPNSTs, male sex and age of 60+ years were independently associated with worse survival. Survival of R1 and that of R0 resections were similar for any location, whereas R2 resections were associated with worse outcomes. Radiotherapy and chemotherapy administrations were not associated with survival.

CONCLUSION

In localized MPNSTs, risk stratification for survival can be done using several patient- and tumour-specific characteristics. Resectability is the most important predictor for survival in MPNSTs. No difference is present between R1 and R0 resections in both retroperitoneal and non-retroperitoneal MPNSTs. The added value of radiotherapy and chemotherapy is unclear.

TYK2 promotes malignant peripheral nerve sheath tumor progression through inhibition of cell death

Background

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas that arise most commonly in the setting of the Neurofibromatosis Type 1 (NF1) cancer predisposition syndrome. Despite aggressive multimodality therapy, outcomes are dismal and most patients die within 5 years of diagnosis. Prior genomic studies in our laboratory identified tyrosine kinase 2 (TYK2) as a frequently mutated gene in MPNST. Herein, we explored the function of TYK2 in MPNST pathogenesis.

Methods

Immunohistochemistry was utilized to examine expression of TYK2 in MPNSTs and other sarcomas. To establish a role for TYK2 in MPNST pathogenesis, murine and human TYK2 knockdown and knockout cells were established using shRNA and CRISPR/Cas9 systems, respectively.

Results

We have demonstrated that TYK2 was highly expressed in the majority of human MPNSTs examined. Additionally, we demonstrated that knockdown of Tyk2/TYK2 in murine and human MPNST cells significantly increased cell death in vitro. These effects were accompanied by a decrease in the levels of activated Stats and Bcl‐2 as well as an increase in the levels of Cleaved Caspase‐3. In addition, Tyk2‐KD cells demonstrated impaired growth in subcutaneous and metastasis models in vivo.

Conclusion

Taken together, these data illustrate the importance of TYK2 in MPNST pathogenesis and suggest that the TYK2 pathway may be a potential therapeutic target for these deadly cancers.