Malignant peripheral nerve sheath tumors of the buttock and lower extremity. A study of 43 cases

Primary schwannoma of the thyroid gland: analysis of case characteristics and review of the literature

BACKGROUND

To improve the characteristics of primary thyroid schwannomas (PTS) and to provide reference basis for clinical diagnosis and treatment.

METHODS

PubMed was searched for case reports of PTS up to December 2022 using the search terms "Thyroid nerve sheath tumor" or "Thyroid schwannoma" or "Thyroid Neurilemmoma", respectively. 34 cases were screened.

RESULTS

PTS can occur at any age, nodules averaged 3.9 cm. The most common symptoms were voice change and dysphagia. Fine needle aspiration cytology showing spindle-shaped cells should be considered for schwannoma. Most cases underwent thyroid lobectomy or nodule removal with a good prognosis. Tissue types with both Antoni A and Antoni B features are common. Positive immunohistochemical staining for S-100 protein, CD34 and waveform proteins helped confirm the diagnosis.

CONCLUSIONS

Positive immunohistochemistry for S-100 and wave proteins helps confirm the diagnosis. Preoperative diagnosis is challenging, but pathology and immunohistochemical staining are the gold standard for diagnosis. The first choice of treatment is surgical resection of the nodules, the prognosis is good.

Contemporary Approach to Neurofibromatosis Type 1-Associated Malignant Peripheral Nerve Sheath Tumors

Most malignant peripheral nerve sheath tumors (MPNSTs) are clinically aggressive high-grade sarcomas, arising in individuals with neurofibromatosis type 1 (NF1) at a significantly elevated estimated lifetime frequency of 8%-13%. In the setting of NF1, MPNSTs arise from malignant transformation of benign plexiform neurofibroma and borderline atypical neurofibromas. Composed of neoplastic cells from the Schwannian lineage, these cancers recur in approximately 50% of individuals, and most patients die within five years of diagnosis, despite surgical resection, radiation, and chemotherapy. Treatment for metastatic disease is limited to cytotoxic chemotherapy and investigational clinical trials. In this article, we review the pathophysiology of this aggressive cancer and current approaches to surveillance and treatment.

Shaping Our Understanding of Malignant Peripheral Nerve Sheath Tumor: A Bibliometric Analysis of the 100 Most-Cited Articles

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) are rare yet highly aggressive soft tissue sarcomas of mesenchymal origin, characterized by a heterogeneous pathological spectrum, limited therapeutic options, and high metastatic potential.

METHODS

Here, the authors conducted a comprehensive bibliometric analysis of the 100 most-cited MPNST articles by utilizing Elsevier's Scopus to identify all relevant published and indexed articles referring to MPNST, thereby aiming to elucidate the pertinent research findings regarding the disease's pathophysiology and therapeutic advancements. Articles were classified as basic science or clinical and analyzed for various bibliometric parameters.

RESULTS

The majority of articles (75%) focused on clinical aspects, reflecting the extensive clinicopathological characterization of MPNSTs. Notable studies investigated prognostic factors, histological and immunohistochemical features, and diagnostic modalities. The identification of loss of function mutations in the polycomb repressive complex 2 emerged as a pivotal role, as it opened avenues for potential targets for novel therapeutic interventions. Newer articles (published in or after 2006) demonstrated higher citation rates, suggesting evolving impact and collaboration.

CONCLUSIONS

This bibliometric analysis showed how developments in the understanding of MPNST pathophysiology and the creation of novel therapeutic strategies occurred throughout time. Changes that have been noticed recently could portend future innovative therapeutic approaches.

Malignant peripheral nerve sheath tumor in the kidney of a dog

A 12-year-old castrated male poodle presented with vomiting and diarrhea. Ultrasonography and computed tomography revealed a protruding mass at the caudal pole of the left kidney. Grossly, the poorly circumscribed abnormal mass was 1.6 × 1.8 × 1.9 cm in size and had multifocal dark-red foci. Microscopically, it was composed of densely or loosely packed variable-sized short spindle or ovoid cells. These neoplastic cells showed high pleomorphism, mitotic figures, and invasive tendency to the adjacent tissue. Immunohistochemically, the neoplastic spindle cells expressed vimentin, S100, neuron-specific enolase, nerve growth factor receptor, and laminin. Therefore, the mass was diagnosed as a malignant peripheral nerve sheath tumor (MPNST). To our knowledge, this is the first report of primary renal MPNST in a dog.

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.

FT895 Impairs Mitochondrial Function in Malignant Peripheral Nerve Sheath Tumor Cells

Neurofibromatosis type 1 (NF1) stands as a prevalent neurocutaneous disorder. Approximately a quarter of NF1 patients experience the development of plexiform neurofibromas, potentially progressing into malignant peripheral nerve sheath tumors (MPNST). FT895, an HDAC11 inhibitor, exhibits potent anti-tumor effects on MPNST cells and enhances the cytotoxicity of cordycepin against MPNST. The study aims to investigate the molecular mechanism underlying FT895's efficacy against MPNST cells. Initially, our study unveiled that FT895 disrupts mitochondrial biogenesis and function. Post-FT895 treatment, reactive oxygen species (ROS) in MPNST notably increased, while mitochondrial DNA copy numbers decreased significantly. Seahorse analysis indicated a considerable decrease in basal, maximal, and ATP-production-coupled respiration following FT895 treatment. Immunostaining highlighted FT895's role in promoting mitochondrial aggregation without triggering mitophagy, possibly due to reduced levels of XBP1, Parkin, and PINK1 proteins. Moreover, the study using CHIP-qPCR analysis revealed a significant reduction in the copy numbers of promoters of the MPV17L2, POLG, TFAM, PINK1, and Parkin genes. The RNA-seq analysis underscored the prominent role of the HIF-1α signaling pathway post-FT895 treatment, aligning with the observed impairment in mitochondrial respiration. In summary, the study pioneers the revelation that FT895 induces mitochondrial respiratory damage in MPNST cells.

Malignant peripheral nerve sheath tumor in the pelvis: a case report

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) are malignancies that arise or differentiate from or infiltrate peripheral nerves and account for approximately 5% of soft-tissue malignancies. Approximately half of MPNSTs develop in patients with neurofibromatosis type 1 (NF1), a hereditary disease. MPNSTs occur mainly in the trunk, proximal extremities, and neck, but can on rare occasion arise in or near the gastrointestinal tract, and intestinal complications have been reported. We describe herein a case with resection of an MPNST arising in the pelvic region.

CASE PRESENTATION

A 51-year-old woman had undergone repeated resections for systemic neurofibrosis associated with NF1. This time, a pelvic tumor was noted on follow-up positron emission tomography computed tomography (CT). She presented with slowly progressive radiating pain in the lower extremities and was referred to our hospital for tumor resection. Contrast-enhanced CT showed a 75 × 58-mm mass in the right greater sciatic foramen directly below a 24 × 28-mm mass. Open pelvic tumor resection was performed for pelvic neurofibroma. The obturator nerve was identified lateral to the main tumor and the sciatic nerve was identified dorsally, then dissection was performed. The closed nerve was spared, while the sciatic nerve was partially dissected and the two tumors were removed. Both tumors were elastic and hard. Pathologic findings were MPNST for the large specimen and neurofibroma with atypia for the small specimen. The patient developed temporary postoperative ileus, but is generally doing well and is currently free of recurrence or radiating pain. The patient is at high risk of recurrence and close monitoring should be continued.

CONCLUSIONS

We encountered a rare case of MPNST. Due to the high risk of recurrence, surgery with adequate margins was performed, with a requirement for appropriate follow-up.

Primary Cardiac Schwannoma: A Meta-Analysis of Individual Case Reports

Primary cardiac schwannoma (PCS) is a neurogenic tumor that arises from Schwann cells. Malignant schwannoma (MSh) is an aggressive cancer comprising 2% of all sarcomas. Information on the proper management of these tumors is limited. Four databases were searched for case reports/series of PCS. The primary outcome was overall survival (OS). Secondary outcomes included therapeutic strategies and the corresponding outcomes. Among 439 potentially eligible studies, 53 met the inclusion criteria. The patients included had 43.72 ± 17.76 years and 28.3% were males. Over 50% of patients had MSh, with 9.4% also demonstrating metastases. Schwannoma commonly occurs in the atria (66.0%). Left-sided PCS were more common than right-sided ones. Surgery was performed in almost 90% of the cases; chemotherapy and radiotherapy were used in 16.9% and 15.1% of cases, respectively. Compared to benign cases, MSh occurs at a younger age and is commonly located on the left side. OS of the entire cohort at 1 and 3 years were 60.7%, and 54.0%, respectively. Females and males OS were similar up to 2 years follow-up. Surgery was associated with higher OS (p < 0.01). Surgery is the primary treatment option for both benign and malignant cases and was the only factor associated with a relative improvement in survival.

Rare case of Malign Peripheral Nerve Sheath Tumor complicating a solitary giant neurofibroma of the thigh

INTRODUCTION AND IMPORTANCE

Malign Peripheral Nerve Sheath Tumor is rare and can occur on a solitary neurofibroma or as part of neurofibromatosis type 1. The occurrence of a giant solitary neurofibroma in the thigh is rare and its complication in MPNST is much rarer. The diagnosis is based on a combination of radiological, histological and immunohistochemical evidence.

CASE PRESENTATION

We present the case of a 55 years old woman who presented a mass of the posterior aspect of the thigh without any other abnormality on systemic examination. MRI showed a T1 hyposignal and a T2 hypersignal and the biopsy performed was in favor of a neurofibroma. After surgical resection, the histological study of the surgical specimen revealed an MPNST developing on a pre-existing neurofibroma. After 5 months, the patient had moderate knee stiffness with thigh amyotrophy.

CLINICAL DISCUSSION

The occurrence of MPNST on a giant solitary neurofibroma of the thigh is extremely rare. MRI allows evoking the diagnosis but radiologists are confronted with a problem of differential diagnosis. Histological examination supports the diagnosis in addition to immunohistochemical examination. Only surgical treatment can give hope for a cure. Recurrences remain frequent with a 5-year survival of 50 %.

CONCLUSION

Early diagnosis is essential to prevent the evolution of the tumor and the occurrence of poor prognostic factors compromising the management, increasing the risk of recurrence and affecting the overall survival of patients.

Malignant peripheral nerve sheath tumor in children: A clinicopathologic and molecular study with parallels to the adult counterpart

Malignant peripheral nerve sheath tumors (MPNST) are aggressive neoplasms, arising either sporadically, in the setting of neurofibromatosis type I (NF1) or post radiation. Most MPNST occur in adults and their pathogenesis is driven by the loss of function mutations in the PRC2 complex, regardless of their clinical presentation. In contrast, pediatric MPNST are rare and their pathogenesis has not been elucidated. In this study, we investigate a large cohort of 64 MPNSTs arising in children and young adults (younger than the age of 20 years) to better define their clinicopathologic and molecular features. Sixteen (25%) cases were investigated by MSK-IMPACT, a targeted NGS panel of 505 cancer genes. Most patients (80%) were aged 11-20 years. A history of NF1 was established in half of the cases. Mean tumor size was 8.5 cm. The most common locations included the extremities (34%) and abdomen/pelvis (27%). Histologically, 89% of high-grade MPNST showed conventional features, while the remaining three cases showed a predominant epithelioid phenotype. Heterologous differentiation occurred in 25% of high grade cases, with half showing rhabdomyoblastic differentiation. Tumors arose in a background of a plexiform neurofibroma (16%), neurofibroma (13%), and schwannoma in two cases (3%). Immunohistochemically, H3K27me3 expression was lost in 82% of conventional high-grade MPNST analyzed, while loss of SMARCB1 expression was seen in one epithelioid MPNST. Genomically, all cases showed more than one genetic abnormality, with 53% showing mutations in EED / SUZ12 genes, and 47% of cases harboring alterations in NF1 and CDKN2A/CDKN2B genes. At the last follow-up, 30% patients died of disease, 28% were alive with disease and 42% had no evidence of disease. NF1 status did not correlate with overall survival. In conclusion, half of pediatric and young adult MPNST were NF1-related and showed loss of function alterations in PRC2 complex, NF1, and CDKN2A, similar to the adult counterpart. Thus, H3K27me3 loss of expression may be used in the diagnosis of high grade MPNSTs in children. Moreover, a small subset of pediatric MPNST have an epithelioid morphology with different pathogenesis.

Metastatic Multifocal Malignant Peripheral Nerve Sheath Tumour in the Cervicothoracic Spinal Cord of a Dog Initially Mimicking Meningomyelitis

A nine year old cross-breed dog was presented with a two week history of ambulatory tetraparesis and proprioceptive ataxia affecting all four limbs. Meningomyelitis of Unknown Origin (MUO) was presumptively diagnosed based on the magnetic resonance imaging (MRI) findings and cerebrospinal fluid (CSF) analysis. The dog received a tapering dose of glucocorticoids and cyclosporine, showing significant improvement and the stabilization of the clinical signs for seven months. After this period, the dog showed an acute clinical deterioration and a follow-up MRI revealed new multiple lesions affecting different spinal nerve roots along the cervicothoracic spinal cord. Following euthanasia, a final diagnose of multiple malignant peripheral nerve sheath tumors (MPNSTs) was made based on the histopathological examination. MPNSTs can affect the cranial nerves, spinal nerves or the associated nerve roots at any location and can lead to secondary spinal cord compression. The aim of the present case report is to describe the clinical presentation and atypical MRI findings of a dog with histologically confirmed multiple MPNSTs. According to the reviewed literature, this is the first reported case of simultaneous MPNSTs in the cervicothoracic spinal cord of a dog.

Evaluating the Evidence: Scientometric Analysis of Highly Cited Neurofibromatosis 1 Publications

The study of Neurofibromatosis 1 (NF1) is progressing rapidly. This study aimed to identify historical trends in publications focusing on NF1, to find the top 100 most cited publications on this topic, and to evaluate their level of evidence. This study identifies historical trends in publication regarding NF1 with the aim of providing readers useful information about the areas of research being performed, an educational guide to facilitate novice researchers in conducting effective evidence-based medical research, and unique insight into developments and trends of NF 1 research. This study also evaluates the evidence of highly cited papers on NF1.

A search of all databases and journals accessible within Elsevier's Scopus was performed on June 27th, 2020, using combinations of the Boolean queries "Neurofibromatosis 1," "Von Recklinghausen," and "NF1," which yielded 13,599 documents. The top 100 most-cited papers were identified, analyzed, and evaluated for level of evidence. Evidence was assessed using the GRADE guidelines.

The top 100 most-cited articles span years 1963-2010 and are published in 50 different journals. The average number of citations per publication was 366.5 (range 189-1527). The most cited article is "Neurofibromatosis: Conference Statement" (Stumpf et al., 1988). In this study, the top 100 most-cited works in NF1 are identified, characterized, and analyzed. This study will serve as a historical point of reference for future research, a jumping point for those unfamiliar with the topic, and an educational foundation for future NF1 specialists and researchers.

Neurofibromin Deficiency Causes Epidermal Growth Factor Receptor Upregulation through the Activation of Ras/ERK/SP1 Signaling Pathway in Neurofibromatosis Type 1-Associated Malignant Peripheral Nerve Sheet Tumor

Neurofibromatosis type 1 (NF1) is an autosomal dominant human genetic disorder. The progression of benign plexiform neurofibromas to malignant peripheral nerve sheet tumors (MPNSTs) is a major cause of mortality in patients with NF1. Although elevated epidermal growth factor receptor (EGFR) expression plays a crucial role in the pathogenesis of MPNST, the cause of EGFR overexpression remains unclear. Here, we assessed EGFR expression levels in MPNST tissues of NF1 patients and NF1 patient-derived MPNST cells. We found that the expression of EGFR was upregulated in MPNST tissues and MPNST cells, while the expression of neurofibromin was significantly decreased. Manipulation of NF1 expression by NF1 siRNA treatment or NF1-GAP-related domain overexpression demonstrated that EGFR expression levels were closely and inversely correlated with neurofibromin levels. Notably, knockdown of the NF1 gene by siRNA treatment augmented the nuclear localization of phosphorylated SP1 (pSP1) and enhanced pSP1 binding to the EGFR gene promoter region. Our results suggest that neurofibromin deficiency in NF1-associated MPNSTs enhances the Ras/ERK/SP1 signaling pathway, which in turn may lead to the upregulation of EGFR expression. This study provides insight into the progression of benign tumors and novel therapeutic approaches for treatment of NF1-associated MPNSTs.

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.

Surgery for Peripheral Nerve Sheath Tumours of the Buttocks, Legs and Feet in 90 Patients With Neurofibromatosis Type 1

BACKGROUND/AIM

Neurofibromatosis type 1 (NF1) is an autosomal dominant tumour predisposition syndrome that can cause plexiform neurofibromas (PNFs). This study examines the surgical procedures that have been performed on large PNFs of the lower extremities.

PATIENTS AND METHODS

Surgical procedures on the lower extremity performed on 90 patients with NF1 with PNFs were evaluated. The topography of the tumours was classified according to dermatomes and functional units.

RESULTS

A total of 243 surgical interventions on the regions of interest were performed. Neurological complications were rarely noted and usually occurred temporarily. There was no preference for dermatomes affected by PNF. The proportion of patients with malignant peripheral nerve sheath tumours (MPNSTs) in this group was 4/90 (4.4%).

CONCLUSION

PNFs often require repeated local interventions to achieve the treatment goal. Local tumour recurrences are to be expected even after extensive tumour reduction. Rapid tumour growth combined with new pain sensations can be signs of a MPNST.

Rapidly Growing Huge Lower Back Malignant Peripheral Nerve Sheath Tumour

Malignant peripheral nerve sheath tumours (also called neurofibrosarcomas) are a rare, highly aggressive soft tissue sarcomas that arise from the peripheral nerves or cells associated with the nerve sheath, such as Schwann cells, peri-neural cells and fibroblasts. It is representing 10% of all soft tissue sarcomas in which it is considered as an extremely rare malignancy, especially in patients with neurofibromatosis type I. In the general population, it affects approximately 1 in 100,000 people. This article is reporting a 56-year-old Malay female patient who is a known case of neurofibromatosis type I for 20 years, presented with a lower back, pruritic, gradually increasing swelling during the last five months. Last month before the presentation, the lesion rapidly grows, reaching a size of (15×15 cm), accompanied by foul-smelling discharge and pain exacerbated with movement. Although no history of preceding trauma or accident, the mass bleeds within contact. In conclusion, only a few cases of giant malignant peripheral nerve sheath tumours reported in the literature describing its location and growth progression. We present a massive, extremely rapid growth of cutaneous exophytic malignant peripheral nerve sheath tumours over the lower back.

Solitary neurofibroma of the larynx: a diagnostic challenge

Solitary neurofibromas of the larynx are extremely rare, with a total of 15 cases described in the literature. Nonetheless, acquaintance with this diagnosis is important, as misdiagnoses can have negative consequences. Presenting symptoms are non-specific and depend on tumour size and location. As well-defined submucosal masses with a broad differential diagnosis, they remain a clinical and radiological challenge. While some characteristics might favour a benign nature and subtle signs might help narrow the differential diagnosis, imaging alone is not sufficient for differentiation and definitive diagnosis requires a biopsy. Complete surgical resection and long-term follow-up is indicated. We share our experience on a case of a solitary laryngeal neurofibroma in a middle-aged woman, presenting with a large well-defined paraglottic lesion.

AXL Inhibition Enhances MEK Inhibitor Sensitivity in Malignant Peripheral Nerve Sheath Tumors

Dysregulation of the receptor tyrosine kinase AXL is known to promote cancer cell growth and survival in many sarcomas, including the rare subtype, malignant peripheral nerve sheath tumors (MPNST). MPNSTs are largely chemoresistant and carry a poor prognosis. AXL is an attractive potential therapeutic target, as it is aberrantly expressed, and its activation may be an early event in MPNST. However, the effect of AXL inhibition on MPNST development and progression is not known. Here, we investigated the role of AXL in MPNST development and the effects of AXL and MEK1/2 co-inhibition on MPNSTs. We used western blotting to examine AXL expression and activation in MPNST cell lines. We analyzed the effects of exogenous growth arrest-specific 6 (GAS6) expression on downstream signaling and the proliferation, migration, and invasion of MPNST cells. The effect of AXL knockdown with or without mitogen-activated protein kinase (MAPK) inhibition on downstream signal transduction and tumorigenesis was also examined in vivo and in vitro. We found that AXL knockdown increased MAPK pathway signaling. This compensation, in turn, abrogated the antitumorigenic effects linked to AXL knockdown in vivo. AXL knockdown, combined with pharmacological MEK inhibition, reduced the proliferation and increased the apoptosis of MPNST cells both in vitro and in vivo. The pharmacological co-inhibition of AXL and MEK1/2 reduced MPNST volumes. Together these findings suggest that AXL inhibition enhances the sensitivity of MPNST to other small molecule inhibitors. We conclude that combination therapy with AXL inhibitor may be a therapeutic option for MPNST.

Fungating malignant peripheral nerve sheath tumor arising from a slow-growing mass in the forearm: a case report and review of the literature

Background

Malignant peripheral nerve sheath tumor is a rare and aggressive form of sarcoma that arises from a peripheral nerve, mostly in association with neurofibromatosis type 1. Half of the cases were reported in the extremities, with the lungs being the most common site of metastasis. We report a rare case of successful limb salvage surgery performed for a large exophytic malignant peripheral nerve sheath tumor of the right forearm with wide surgical margins followed by split-thickness skin graft and later a flexor carpi radialis tendon transfer to extensor digitorum communis tendon.

Case presentation

A 51-year-old Bedouin Arabic man presented to our institution with an incompletely excised, large, fungating, malignant peripheral nerve sheath tumor occupying most of his right forearm. Staging imaging showed multiple lung nodules. He underwent wide local excision followed by skin graft and tendon transfer as a palliative measure to preserve the function of his dominant limb. The operation was performed without any complications, and the patient had an excellent postoperative result. Afterward, he was started on multiple lines of chemotherapy that failed because of disease progression, and the patient died 7 months after the operation.

Conclusion

Clinicians must consider the possibility of soft tissue sarcoma even in a patient with a small, slow-growing, superficial mass. Furthermore, a wrong open biopsy or nononcological surgical procedure may lead to possible contamination and ultimately a more radical procedure than would have originally been necessary, where this can be prevented by an early referral to a highly specialized sarcoma center.

Diagnosis and management of malignant peripheral nerve sheath tumors: Current practice and future perspectives

One of the most common malignancies affecting adults with the neurofibromatosis type 1 (NF1) cancer predisposition syndrome is the malignant peripheral nerve sheath tumor (MPNST), a highly aggressive sarcoma that typically develops from benign plexiform neurofibromas. Approximately 8-13% of individuals with NF1 will develop MPNST during young adulthood. There are few therapeutic options, and the vast majority of people with these cancers will die within 5 years of diagnosis. Despite efforts to understand the pathogenesis of these aggressive tumors, the overall prognosis remains dismal. This manuscript will review the current understanding of the cellular and molecular progression of MPNST, diagnostic workup of patients with these tumors, current treatment paradigms, and investigational treatment options. Additionally, we highlight novel areas of preclinical research, which may lead to future clinical trials. In summary, MPNST remains a diagnostic and therapeutic challenge, and future work is needed to develop novel and rational combinational therapy for these tumors.

Successful Management of Intrathoracic Phrenic Malignant Peripheral Nerve Sheath Tumor by Multimodal Treatment

Malignant peripheral nerve sheath tumors (MPNSTs) are rare and can be associated with type 1 neurofibromatosis. They are rarely located at the mediastinum, most often at the posterior mediastinal compartment or the paravertebral gutters. MPNSTs of the anterior mediastinum arising from the phrenic nerve are exceptional. Their prognosis is poor due to the high potential of local tumor recurrence and metastasis. Complete surgical resection remains the only radical treatment. However, the outcomes after this treatment alone cannot be considered satisfactory. Preoperative chemotherapy could be an interesting therapeutic option for unresectable tumors. We report here the case of a 77-year-old woman with an MPNST located at the anterior mediastinum arising from the phrenic nerve. This tumor was successfully managed with multimodal therapy combining preoperative chemotherapy, complete surgery and adjuvant radiation.

Malignant peripheral nerve sheath tumour of thyroid: a diagnostic dilemma

Malignant peripheral nerve sheath tumours of thyroid are rare entities that can present a diagnostic dilemma. We present the case of a patient who presented with neck mass with a history of multiple neck surgeries and airway compression. The patient's previous histopathology was mistaken for Riedel's thyroiditis in an outside hospital, which delayed appropriate treatment leading to suffering on part of the patient and frustration on part of the physician. We emphasise that rare malignancies should be considered in rapidly growing neck masses that are causing airway compression, and histopathology of such tumours should be reported by expert pathologists.

Synovial Sarcoma of the Nerve-Clinical and Pathological Features: Case Series and Systematic Review

BACKGROUND

Synovial sarcoma of the nerve is a rare entity with several cases and case series reported in the literature. Despite an improved understanding of the biology, the clinical course is difficult to predict.

OBJECTIVE

To compile a series of patients with synovial sarcoma of the peripheral nerve (SSPN) and assess clinical and pathological factors and their contribution to survival and recurrence.

METHODS

Cases from 2 institutions collected in patients undergoing surgical intervention for SSPN. Systematic review including PubMed and Scopus databases were searched for related articles published from 1970 to December 2018. Eligibility criteria: (1) case reports or case series reporting on SSPN, (2) clinical course and/or pathological features of the tumor reported, and (3) articles published in English.

RESULTS

From patients treated at our institutions (13) the average follow-up period was 3.2 yr. Tumor recurrence was seen in 4 cases and death in 3. Systematic review of the literature yielded 44 additional cases with an average follow-up period of 3.6 yr. From pooled data, there were 10 recurrences and 7 deaths (20% and 14%, respectively). Adjuvant treatment used in 62.5% of cases. Immunohistochemical markers used in diagnosis varied widely; the most common are the following: Epithelial membrane antigen (EMA), cytokeratin, vimentin, cluster of differentiation (CD34), and transducin-like enhancer of split 1 (TLE1). Statistical analysis illustrated tumor size and use of chemotherapy to be negative predictors of survival. No other factors, clinically or from pathologist review, were correlated with recurrence or survival.

CONCLUSION

By combining cases from our institution with historical data and performing statistical analysis we show correlation between tumor size and death.

Genomics of MPNST (GeM) Consortium: Rationale and Study Design for Multi-Omic Characterization of NF1-Associated and Sporadic MPNSTs

The Genomics of Malignant Peripheral Nerve Sheath Tumor (GeM) Consortium is an international collaboration focusing on multi-omic analysis of malignant peripheral nerve sheath tumors (MPNSTs), the most aggressive tumor associated with neurofibromatosis type 1 (NF1). Here we present a summary of current knowledge gaps, a description of our consortium and the cohort we have assembled, and an overview of our plans for multi-omic analysis of these tumors. We propose that our analysis will lead to a better understanding of the order and timing of genetic events related to MPNST initiation and progression. Our ten institutions have assembled 96 fresh frozen NF1-related (63%) and sporadic MPNST specimens from 86 subjects with corresponding clinical and pathological data. Clinical data have been collected as part of the International MPNST Registry. We will characterize these tumors with bulk whole genome sequencing, RNAseq, and DNA methylation profiling. In addition, we will perform multiregional analysis and temporal sampling, with the same methodologies, on a subset of nine subjects with NF1-related MPNSTs to assess tumor heterogeneity and cancer evolution. Subsequent multi-omic analyses of additional archival specimens will include deep exome sequencing (500×) and high density copy number arrays for both validation of results based on fresh frozen tumors, and to assess further tumor heterogeneity and evolution. Digital pathology images are being collected in a cloud-based platform for consensus review. The result of these efforts will be the largest MPNST multi-omic dataset with correlated clinical and pathological information ever assembled.

Malignant peripheral nerve sheath tumour – A long story: Case report

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Segmental neurofibromatosis with MPNST showing multiple recurrences has not been reported in literature.

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Studies were not conducted regarding the survival rate of such patients due to its extreme low incidence.

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Being considered as a highly aggressive sarcoma, our patient with MPNST survived for a long period without distant metastasis.

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Maintenance of old records helped to carry out review workup effectively.

Introduction

We present a rare case of Malignant Peripheral Nerve Sheath Tumour (MPNST) of the upper limb, which was excised thirteen times in thirteen years and ultimately ended in above elbow amputation.

Presenting complaint and investigations

A 48 year old female presented initially with a localised swelling of 2 cms diameter in the front of the left elbow in 2007, which was excised. It recurred repeatedly and was excised. In the earlier presentations, the swellings were firm, mobile and not fixed to bone. In the last stage alone, bone fixity was identified. All the fourteen surgeries were performed by the primary author from 2007 to 2020, as the patient was particular.

The main clinical diagnoses

had been neurofibroma and fibrosarcoma. There was no evidence of distant metastasis all these years. She did not respond to radiation or chemotherapy. Initially it was single, but later multiple. She had no clinical features of Neurofibromatosis 1 (NF1) or any family history. As the history progressed, the swellings became muscle deep and later encircled the radial nerve. The radial nerve was salvaged on three occasions. On the last three occasions, the tumour had to be shaved off from the humerus. The final amputation specimen showed a single tumour infiltrating the humerus and x-ray revealed bone destruction and tumour calcification. Final diagnosis was aided by immunohistochemistry (IHC) and cytogenetic study (FISH).

Conclusion

The case is presented for the rarity of the presentation and the trust and dependence of the patient on her personal surgeon.

Malignant peripheral nerve sheath tumour-A case report

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Pre-sacral mass presenting with right thigh shooting pain in the setting of Von Recklinghausen.

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Radiological imaging was crucial in providing a road map pre-op.

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Mass abutting the internal iliac artery and possibly pressing on the sacral nerve roots.

Introduction

Malignant peripheral nerve sheath tumors (MPNST) are rare, aggressive sarcomatous tumors that arise from peripheral nerve sheaths and show schwann cell differentiation (Thangadurai, 2017) [1]. They commonly arise among patients with neurofibromatosis I and following radiation therapy (Farid et al., 2014). High resolution PET scans confirm the diagnosis and the definitive treatment is surgical excision. Post operative radiotherapy plays an important role in disease free survival rates. Chemotherapy is offered to people who have a systemic disease.

Presentation of case

This case report is on a 47 year old lady, a known case of Von Recklinghausen, who complained of a vague mass in the pelvis with recent history of pain to her right thigh. Pelvic examination revealed a vague mass on the right side of her pelvis. She was planned for excision of the mass. Intraoperative findings were consistent with the clinical and radiological findings. She is currently on regular follow-up and disease free.

Discussion

MPNSTs are rare tumours that arise in patients with neurofibromatosis I. Mutations at the genetic level is responsible for the development of MPNST. Early presentation, radiological confirmation, aggressive margin free surgery followed by chemoradiation helps in near complete cure of the disease.

Conclusion

MPNST are difficult to manage because of their aggressive nature and the limitations in early diagnosis and management. In patients with Von Recklinghausens disease, malignancy must be suspected when a patient presents with the complaints as mentioned in this case report.

Clinical presentation and long-term outcome of primary spinal intradural malignant peripheral nerve sheath tumors

OBJECTIVE

Primary spinal intradural malignant peripheral nerve sheath tumors (MPNSTs) are exceedingly rare, and there is limited published information regarding these lesions. The purpose of this study was to analyze the clinical course, treatment, and outcome of primary spinal intradural MPNSTs.

PATIENTS AND METHODS

A retrospective study was performed on 8 patients with primary spinal intradural MPNSTs who were surgically treated and pathologically confirmed in our institution between 2007 and 2018.

RESULTS

There were 3 females and 5 males, with a median age of 46.5 years (range, 21-68 years). Limb weakness was the most common clinical symptom (5/8, 62.5%). The radiological diagnosis was meningioma or schwannoma in most patients (7/8, 87.5%). Malignancies were graded high in 5 cases (62.5%) and low in 3 cases (37.5%). Gross total resection (GTR) was performed in 5 cases, while subtotal resection (STR) was achieved in 3 cases. The mean follow-up period was 48.9 months (range, 10-160 months). During follow-up, local recurrence occurred in 6/8 cases (75.0%) and distant metastasis occurred in 2/8 cases (25.0%). The median survival time (MST) of these 8 patients was 21.0 months. The overall 1-year, 2-year, and 5-year survival rates were 87.5% (7/8), 50.0% (4/8), and 25.0% (2/8), respectively.

CONCLUSIONS

Primary spinal intradural MPNST is a challenging clinical entity given its high local relapse rate. Primary spinal intradural MPNSTs radiologically present themselves heterogeneous and thus difficult to distinguish from schwannomas or meningiomas. Surgical resection, especially GTR, is the preferential treatment for primary spinal intradural MPNSTs.

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.

Central nervous system metastasis of an intradural malignant peripheral nerve sheath tumor in a dog

An 8-yr-old French Bulldog was presented with a non-ambulatory tetraparesis. Magnetic resonance showed an intradurally located mass at the level of the right second cervical nerve root. The mass was surgically removed and the dog was ambulatory within 4 d. A 10-mo post-surgical imaging follow-up revealed a recurrence of the primary mass and another intradural/intramedullary mass at the level of the first thoracic vertebral body. Overall histological features were suggestive of malignant peripheral nerve sheath tumor (MPNST) for both masses. Immunohistochemistry was found weak but diffusely positive for S-100 and neurono-specific enolase for both masses. A diagnosis of primary MPNST for the cervical mass and of metastasis for the thoracic mass was made, possibly disseminated via the subarachnoidal space. To our knowledge, the central nervous system metastasis of MPNSTs has not previously been reported in dogs. The clinician should be aware that these tumors, albeit rarely, can metastasize to the central nervous system.

Malignant Peripheral Nerve Sheath Tumors: A Single Institution's Experience Using Combined Surgery and Radiation Therapy

PURPOSE

The purpose of this study is to investigate local control (LC), survival outcomes, and associated prognostic factors for patients with malignant peripheral nerve sheath tumors (MPNSTs) treated with combined surgery and radiation therapy (RT).

METHODS

We reviewed the medical records of 71 consecutive patients treated with surgery and RT for localized MPNST between 1965 and 2012. Preoperative RT was used to treat 23 patients (32%) to a median dose of 50 Gy (range, 50 to 60 Gy), whereas 48 (68%) received postoperative RT to a median dose of 64 Gy (range, 45 to 70 Gy).

RESULTS

Median follow-up for living patients was 118 months (range, 21 to 512 mo). The 5-year LC, distant metastatic free survival, and disease-specific survival rates were 84%, 62%, and 66%, respectively. To identify predictors of outcome, several multivariate models were constructed: (1) positive/uncertain surgical margin status was the only factor adversely associated local relapse at 5 years (28% vs. 5% for negative margins; P=0.02; hazard ratios 5.92; 95% confidence interval, 1.3-27.4). (2) No factors were significantly associated with distant metastatic free survival. Of the 35 patients (49%) who sustained disease relapse, only 3 were ultimately salvaged. Only 2 patients had grade 2 late toxicities (necrosis, fibrosis) based on Common Terminology Criteria for Adverse Events version 4.03 criteria, and 1 patient had grade 1 edema.

CONCLUSIONS

Combination therapy with surgery and RT provides favorable LC. Distant recurrences, however, continue to be challenging with limited salvage success at the time of relapse.

Malignant peripheral nerve sheath tumours and neurofibromatosis 1: A case series and recommendations for care

Background: The incidence of malignant peripheral nerve sheath tumours (MPNST) in patients with neurofibromatosis 1 (NF1) is significantly higher than that of the general population. NF1-associated MPNST occur at a younger age and carry a worse prognosis than sporadic MPNST.Aim: This case series describes four cases of MPNST in patients with NF1.Setting: The study was performed in a public academic hospital in the Western Cape province of South Africa.Method: Demographics, disease status, histopathology, treatment and outcome data were collected retrospectively from medical charts and through review of histological slides.Results: The median age was 36.5 years. All tumours were > 5 cm at presentation and located on the trunk. One patient presented with metastatic disease. There was a mean delay of 3.5 months from presentation to initiation of treatment. Three patients underwent wide excision, with one receiving adjuvant chemotherapy and radiotherapy. At a median follow-up of 20 months from histological diagnosis only one patient was alive in clinical remission. Two patients had succumbed to progressive disease at 8 and 16 months from diagnosis and one patient with terminal metastatic disease was lost to follow-up.Conclusion: In this series the patients presented with advanced, often unresectable lesions for which single modality therapy was not curative. An adult NF1 health surveillance guideline for resource-constrained environments could lead to early diagnosis and treatment of MPNST and other complications in NF1 patients.

Treatment and survival differences across tumor sites in malignant peripheral nerve sheath tumors: a SEER database analysis and review of the literature

Background

Currently, literature is scarce on differences across all possible tumor sites in malignant peripheral nerve sheath tumors (MPNSTs). To determine differences in treatment and survival across tumor sites and assess possible predictors for survival, we used the Surveillance, Epidemiology, and End Results (SEER) database.

Methods

MPNST cases were obtained from the SEER database. Tumor sites were recoded into: intracranial, spinal, head and neck (H&N), limbs, core (thorax/abdomen/pelvis), and unknown site of origin. Patient and tumor characteristics, treatment modalities, and survival were extracted. Overall survival (OS) was assessed using univariable and multivariable Cox regression hazard models. Kaplan-Meier survival curves were constructed per tumor site for OS and disease-specific survival (DSS).

Results

A total of 3267 MPNST patients were registered from 1973 to 2013; 167 intracranial (5.1%), 119 spinal (3.6%), 449 H&N (13.7%), 1022 limb (31.3%), 1307 core (40.0%), and 203 unknown (6.2%). The largest tumors were found in core sites (80.0 mm, interquartile range [IQR]: 60.0-115.0 mm) and the smallest were intracranial (37.4 mm, IQR: 17.3-43.5 mm). Intracranial tumors were least frequently resected (58.1%), whereas spinal tumors were most often resected (83.0%). Radiation was administered in 35.5% to 41.8%. Independent factors associated with decreased survival were: older age, male sex, black race, no surgery, partial resection, large tumor size, high tumor grade, H&N site, and core site (all P < .05). Intracranial and pediatric tumors show superior survival (both P < .05). Intracranial tumors show superior OS and DSS curves, whereas core tumors have the worst (P < .001).

Conclusion

Superior survival is seen in intracranial and pediatric MPNSTs. Core and H&N tumors have a worse prognosis.

Salvage of the Foot for Recurrent Malignant Peripheral Nerve Sheath Tumor

Malignant peripheral nerve sheath tumors are rare soft tissue tumors accounting for 3% to 10% of all soft tissue tumors. They are strongly related to neurofibromatosis type 1, an autosomal dominant disease, and are characterized by aggressive biologic behavior, high local recurrence rates, and frequent metastases. Although the major nerves of the lower extremities are a common location of these tumors, scarce cases have been reported of malignant peripheral nerve sheath tumors involving the interdigital nerves of the foot. We report the case of a patient with non-neurofibromatosis type 1 and a recurrent malignant peripheral nerve sheath tumor of the first interdigital nerve of the foot treated successfully with limb salvage surgery with wide resection margins and reconstruction with an autogenous fibula graft.

Aberrant ATRX protein expression is associated with poor overall survival in NF1-MPNST

Malignant Peripheral Nerve Sheath Tumors (MPNSTs) are aggressive soft tissue sarcomas that can occur sporadically or in the setting of the Neurofibromatosis type 1 (NF1) cancer predisposition syndrome. These tumors carry a dismal overall survival. Previous work in our lab had identified ATRX chromatin remodeler (ATRX), previously termed, Alpha Thalassemia/Mental Retardation Syndrome X Linked as a gene mutated in a subset of MPNSTs. Given the great need for novel biomarkers and therapeutic targets for MPNSTs, we sought to determine the expression of ATRX in a larger subset of sporadic and NF1 associated MPNSTs (NF1-MPNSTs). We performed immunohistochemistry (IHC) on 74 MPNSTs (43 NF1-associated and 31 sporadic), 21 plexiform neurofibromas, and 9 atypical neurofibromas. Using this approach, we have demonstrated that 58% (43/74) of MPNSTs have aberrant ATRX expression (<80% nuclear expression) compared to only 7% (2/30) of benign (plexiform and atypical) neurofibromas. Second, we demonstrated that 65% (28/43) of NF1-MPNSTs displayed aberrant ATRX expression as did 48% (15/31) of sporadic MPNSTs. Finally, we show that aberrant ATRX expression was associated with a significantly decreased overall survival for patients with NF1-MPNST (median OS of 17.9 months for aberrant expression and median OS not met (>120 months) for intact expression, p = 0.0276). In summary, we demonstrate that ATRX is aberrantly expressed in the majority of NF1-MPNSTs, but not plexiform or atypical neurofibromas. Additionally, aberrant ATRX expression is associated with decreased overall survival in NF1-MPNST, but not sporadic MPNST and may serve as a prognostic marker for patients with NF1-MPNST.

Radiation-Induced Schwannomas of the Neuraxis. Report of Three Cases

We report 3 cases of possible radiation-induced schwannomas observed in our Department. Their salient clinical and pathogenetic features are analyzed and the role of radiation therapy in the oncogenesis of these lesions is discussed. Several cases of radiation-induced tumors, including some of the nervous system, have been reported, but schwannomas have only occasionally been reported in connection with ionizing radiation. The possible adjuvant role of antineoplastic drugs is also discussed, and the literature on this topic is reviewed.

Malignant Peripheral Nerve Sheath Tumor

Malignant peripheral nerve sheath tumor (MPNST) is the sixth most common type of soft tissue sarcoma. Most MPNSTs arise in association with a peripheral nerve or preexisting neurofibroma. Neurofibromatosis type is the most important risk factor for MPNST. Tumor size and fludeoxyglucose F 18 avidity are among the most helpful parameters to distinguish MPNST from a benign peripheral nerve sheath tumor. The histopathologic diagnosis is predominantly a diagnosis of light microscopy. Immunohistochemical stains are most helpful to distinguish high-grade MPNST from its histologic mimics. Current surgical management of high-grade MPNST is similar to that of other high-grade soft tissue sarcomas.

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.

Multicompartmental Primary Spinal Extramedullary Tumors: Value of an Interdisciplinary Approach

Background:

Primary extramedullary tumors involving multiple compartments around the spine are a technically demanding group of tumors whose extent traverses beyond the normal confines of those anatomical regions which fall in the common domain of neurosurgeons. In the following series, we present 12 patients who were diagnosed with primary spinal extramedullary tumors with multicompartmental extension, and whose surgical management was facilitated by a combined multidisciplinary approach involving surgeons of other superspecialties. This multidisciplinary assistance from the inception to the culmination of surgical management helped in achieving a better surgical removal, thereby resulting in better surgical outcomes.

Materials and Methods:

Twelve consecutive patients who fulfilled the inclusion criteria in the 5-year period (January 2010 to January 2015) were included in the series based on the radiological and pathological characteristics of the tumor. Depending on the site of the spine involved by the lesion, radiologists and surgeons were involved from the planning phase of the surgical management, and their assistance in procedures such as preoperative embolization/ureteric stenting was sought whenever was deemed necessary. The extent of resection and total blood loss was recorded meticulously. Regular follow-up (3, 6, and 12 months and 2 and 5 years) of the patients was done after the initial follow-up at 6 weeks and their disability scores were recorded.

Results:

Of the 12 cases (6 males and 6 females), sacrum was the most common location of the tumors (6). Histopathologically, giant-cell tumors, schwannomas, and chondrosarcomas (3 each) were most common followed by Ewing's sarcoma (2) and malignant peripheral nerve sheath tumor (1). Eight patients had functional status of McCormick scale 1 and two patients had a functional status of 2. One patient was lost to follow-up and one patient died during surgery.

Conclusion:

Judicious involvement of access surgeons and adjunct therapies along with careful preoperative planning can help in improving surgical outcome in multicompartmental spinal tumors.

Role of Histone H3K27 Trimethylation Loss as a Marker for Malignant Peripheral Nerve Sheath Tumor in Fine-Needle Aspiration and Small Biopsy Specimens

OBJECTIVES

Accurate diagnosis of malignant peripheral nerve sheath tumor (MPNST) is often challenging on fine-needle aspiration (FNA) or core needle biopsy. Recurrent mutations in EED and SUZ12, which encode subunits of polycomb repressive complex 2 (PRC2), have been identified in 70% to 92% of MPNSTs; PRC2 inactivation leads to loss of trimethylation of lysine 27 of histone H3 (H3K27me3). We evaluated the utility of H3K27me3 immunohistochemistry for distinguishing MPNST from its cytomorphologic mimics.

METHODS

H3K27me3 immunohistochemistry was performed on 180 cases of spindle cell neoplasms sampled by FNA (n = 66) and needle biopsy (n = 114), and loss of nuclear staining was scored. Tumor types included MPNST, dedifferentiated liposarcoma, schwannoma, solitary fibrous tumor, leiomyosarcoma, melanoma, synovial sarcoma, sarcomatoid carcinoma, gastrointestinal stromal tumor, desmoid fibromatosis, low-grade fibromyxoid sarcoma, and unclassified spindle cell sarcoma/undifferentiated pleomorphic sarcoma.

RESULTS

Complete loss of H3K27me3 was observed in 54% (13/24) of MPNSTs. In contrast, only two (of 156) histologic mimics showed complete loss of H3K27me3. Partial loss of H3K27me3 was present in a subset of cases (26/180), including both MPNST and non-MPNSTs.

CONCLUSIONS

Complete loss of H3K27me3 is a highly specific (98.7%) marker of MPNST that can distinguish MPNST from cytomorphologic mimics in FNA cell block and small biopsy specimens.

MAGEA4 expression in bone and soft tissue tumors: its utility as a target for immunotherapy and diagnostic marker combined with NY-ESO-1

Cancer-testis (CT) antigens have promise as targets for immunotherapy, because of their restricted expression in tumor or testis tissue. MAGEA4 is both a MAGE family member and a CT antigen, and has attracted attention as a potential immunotherapeutic target. We investigated MAGEA4 expression by immunohistochemistry in bone and soft tissue tumor specimens that consisted of 35 malignant or intermediate and 24 benign histological subtypes, in order to evaluate its possible utility as an immunotherapy target and its potential use as a diagnostic marker when combined with another CT antigen, NY-ESO-1. Among these tumors, MAGEA4 was detected in 82.2% of synovial sarcomas, 67.7% of myxoid liposarcomas, 43.8% of osteosarcomas, 41.4% of angiosarcomas, 24.6% of malignant peripheral nerve sheath tumors (MPNSTs), and 21.4% of chondrosarcomas. NY-ESO-1 expression was found in 88.2% of myxoid liposarcomas, 61.1% of synovial sarcomas, 31.3% of osteosarcomas, 21.4% of pleomorphic liposarcomas, 16.7% of desmoplastic small round cell tumors, and 14.3% of chondrosarcomas. Benign tumors and non-tumorous tissue, except for testis tissue, did not express MAGEA4 or NY-ESO-1. Combined use of MAGEA4 and NY-ESO-1 increased the sensitivity, specificity, positive predictive values, and negative predictive values for distinguishing synovial sarcoma from spindle cell tumors and other mimicking tumors, compared to individual use of MAGEA4 or NY-ESO-1. Our results support the immunotherapy targeting MAGEA4 or NY-ESO-1 can be an ancillary therapy in the above-mentioned tumors, and the potential utility of MAGEA4 as an ancillary diagnostic marker for synovial sarcoma combined with NY-ESO-1.

Hypoxia-inducible factor 1 alpha is a poor prognostic factor and potential therapeutic target in malignant peripheral nerve sheath tumor

Background

Malignant peripheral nerve sheath tumor (MPNST) is a rare soft tissue sarcoma with poor prognosis. Hypoxia-inducible factor 1 (HIF-1) plays a crucial role in the cellular response to hypoxia and regulates the expression of multiple genes involved in tumor progression in various cancers. However, the importance of the expression of HIF-1α in MPNSTs is unclear.

Methods

The expression of HIF-1α was examined immunohistochemically in 82 MPNST specimens. Cell culture assays of human MPNST cells under normoxic and hypoxic conditions were used to evaluate the impact of anti-HIF-1α–specific siRNA inhibition on cell survival. A screening kit was employed to identify small molecules that inhibited HIF-1α.

Results

The nuclear expression of HIF-1α was positive in 75.6% of MPNST samples (62/82 cases). Positivity for HIF-1α was a significant poor prognostic factor both in univariate (P = 0.048) and multivariate (P ≤ 0.0001) analyses. HIF-1α knockdown abrogated MPNST cell growth, inducing apoptosis. Finally, chetomin, an inhibitor of HIF-1α, effectively inhibited the growth of MPNST cells and induced their apoptosis.

Conclusion

Inhibition of HIF-1α signaling is a potential treatment option for MPNSTs.

Spatially- and temporally-controlled postnatal p53 knockdown cooperates with embryonic Schwann cell precursor Nf1 gene loss to promote malignant peripheral nerve sheath tumor formation

Malignant peripheral nerve sheath tumors (MPNSTs) are highly aggressive sarcomas that arise sporadically or in association with the Neurofibromatosis type 1 (NF1) cancer predisposition syndrome. In individuals with NF1, MPNSTs are hypothesized to arise from Nf1-deficient Schwann cell precursor cells following the somatic acquisition of secondary cooperating genetic mutations (e.g., p53 loss). To model this sequential genetic cooperativity, we coupled somatic lentivirus-mediated p53 knockdown in the adult right sciatic nerve with embryonic Schwann cell precursor Nf1 gene inactivation in two different Nf1 conditional knockout mouse strains. Using this approach, ∼60% of mice with Periostin-Cre-mediated Nf1 gene inactivation (Periostin-Cre; Nf1^flox/flox mice) developed tumors classified as low-grade MPNSTs following p53 knockdown (mean, 6 months). Similarly, ∼70% of Nf1+/− mice with GFAP-Cre-mediated Nf1 gene inactivation (GFAP-Cre; Nf1^flox/null mice) developed low-grade MPNSTs following p53 knockdown (mean, 3 months). In addition, wild-type and Nf1+/− mice with GFAP-Cre-mediated Nf1 loss develop MPNSTs following somatic p53 knockout with different latencies, suggesting potential influences of Nf1+/− stromal cells in MPNST pathogenesis. Collectively, this new MPNST model system permits the analysis of somatically-acquired events as well as tumor microenvironment signals that potentially cooperate with Nf1 loss in the development and progression of this deadly malignancy.

Clinical genomic profiling identifies TYK2 mutation and overexpression in patients with neurofibromatosis type 1-associated malignant peripheral nerve sheath tumors

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas that arise at an estimated frequency of 8% to 13% in individuals with neurofibromatosis type 1 (NF1). Compared with their sporadic counterparts, NF1-associated MPNSTs (NF1-MPNSTs) develop in young adults, frequently recur (approximately 50% of cases), and carry a dismal prognosis. As such, most individuals affected with NF1-MPNSTs die within 5 years of diagnosis, despite surgical resection combined with radiotherapy and chemotherapy.

METHODS

Clinical genomic profiling was performed using 1000 ng of DNA from 7 cases of NF1-MPNST, and bioinformatic analyses were conducted to identify genes with actionable mutations.

RESULTS

A total of 3 women and 4 men with NF1-MPNST were identified (median age, 38 years). Nonsynonymous mutations were discovered in 4 genes (neurofibromatosis type 1 [NF1], ROS proto-oncogene 1 [ROS1], tumor protein p53 [TP53], and tyrosine kinase 2 [TYK2]), which in addition were mutated in other MPNST cases in this sample set. Consistent with their occurrence in individuals with NF1, all tumors had at least 1 mutation in the NF1 gene. Whereas TP53 gene mutations are frequently observed in other cancers, ROS1 mutations are common in melanoma (15%-35%), another neural crest-derived malignancy. In contrast, TYK2 mutations are uncommon in other malignancies (<7%). In the current series, recurrent TYK2 mutations were identified in 2 cases of NF1-MPNST (30% of cases), whereas TYK2 protein overexpression was observed in 60% of MPNST cases using an independently generated tissue microarray, regardless of NF1 status.

CONCLUSIONS

Clinical genomic analysis of the current series of NF1-MPNST cases found that TYK2 is a new gene mutated in MPNST. Future work will focus on examining the utility of TYK2 expression as a biomarker and therapeutic target for these cancers. Cancer 2017;123:1194-1201. © 2016 American Cancer Society.

Large Cervical Vagus Nerve Tumor in a Patient with Neurofibromatosis Type 1 Treated with Gross Total Resection: Case Report and Review of the Literature

Neurofibromas are benign peripheral nerve sheath tumors that occur commonly in individuals with neurocutaneous disorders such as neurofibromatosis type 1. Vagal nerve neurofibromas, however, are a relatively rare occurrence. We present the case of a 22-year-old man with neurofibromatosis type 1 with a neurofibroma of the left cervical vagal nerve. The mass was resected through an anterior approach without major event. In the postoperative course, the patient developed left vocal cord paralysis treated with medialization with injectable gel. We then present a comprehensive review of the literature for surgical resection of vagal nerve neurofibromas.

Orbital Malignant Peripheral Nerve Sheath Tumor With Heterologous Elements in a 15-Year-Old Girl

A 15-year-old girl presented with painful proptosis in the right eye. Imaging studies demonstrated an inferiorly located orbital mass. Histopathological examination of the exenteration specimen was consistent with malignant peripheral nerve sheath tumor. This case is a rare example of orbital malignant peripheral nerve sheath tumor presumably arising from the infraorbital nerve with heterologous histologic elements.