Nerve Sheath Tumors Research Articles

Supraspinous Fossa: Anatomy and Pathology

AbstractSupraspinous fossa is an important location in the periscapular region, which houses important structures such as the supraspinatus muscle and the suprascapular nerve. The supraspinous fossa can be affected by pathologies involving its contents (supraspinatus muscle and suprascapular nerve), osseous boundary (scapular body, distal clavicle, and spinous process), or superficial soft tissue covering it. In this pictorial review, we describe the detailed anatomy of the supraspinous fossa. We have also covered imaging of wide range of pathologies that can affect supraspinous fossa such as paralabral cyst, muscle edema/atrophy, malignancies (primary and secondary), and miscellaneous lesions (myositis ossificans, fibromatosis, nerve sheath tumor, etc.). An awareness of the imaging findings of these entities is essential for a radiologist to avoid misinterpretation and can aid a timely diagnosis.

Enhanced IL-12 transgene expression improves oncolytic viroimmunotherapy.

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas with unacceptably low cure rates occurring often in patients with neurofibromatosis 1 defects. To investigate oncolytic Herpes Simplex Virus (oHSV) as an immunotherapeutic approach, we compared viral replication, functional activity, and immune response between unarmed and interleukin 12 (IL-12)-armed oncolytic viruses in virus-permissive (B109) and -resistant (67C-4) murine MPNSTs. This study compared two attenuated IL-12-oHSVs with γ134.5 gene deletions (Δγ134.5) and the same transgene expression cassette. The primary difference in the IL-12-oHSVs was in their ability to counter the translational arrest response in infected cells. Unlike M002 (Δγ134.5, mIL-12), C002 (Δγ134.5, mIL-12, IRS1) expresses an HCMV IRS1 gene and evades dsRNA activated translational arrest in infected cells. Our results show that oHSV replication and gene expression results in vitro were not predictive of oHSV direct oncolytic activity in vivo. Tumors that supported viral replication in cell culture studies resisted viral replication by both oHSVs and restricted M002 transgene expression in vivo. Furthermore, two IL-12-oHSVs with equivalent transcriptional activity differed in IL-12 protein production in vivo, and the differences in IL-12 protein levels were reflected in immune infiltrate activity changes as well as tumor growth suppression differences between the IL-12-oHSVs. C002-treated tumors exhibited sustained IL-12 production with improved dendritic cells, monocyte-macrophage activity (MHCII, CD80/CD86 upregulation) and a polyfunctional Th1-cell response in the tumor infiltrates. These results suggest that transgene protein production differences between oHSVs in vivo, in addition to replication differences, can impact OV-therapeutic activity.

Systemic therapy in NF-1 associated malignant peripheral nerve sheath tumors (MPNST).

11583 Background: MPNST are rare sarcomas that have a poor prognosis and are challenging to treat. Around 50% of MPNSTs are associated with NF1, 40% are sporadic, and 10% are radiation-associated. Doxorubicin (D) based chemotherapy (CT) regimens are commonly used in the front-line, and combinations have better response rates than single agents. Response to second-line regimens is not well documented. The objective of this study is to document efficacy of systemic regimens in MPNST as a benchmark for future novel therapeutics in this space. Methods: 72 patients (pts) with NF1-associated MPNSTs in an MD Anderson database were reviewed retrospectively from EMR. Variables collected included demographics, primary MPNST location, localized vs metastatic, and treatments received (+/- radiation, +/-surgery, +/- lines of CT). Responses (progressive disease (PD), stable disease (SD), partial response (PR)) as interpreted by treating physician and radiology reports and time on treatment for 1st and 2nd line chemotherapy regimens were assessed. Cox proportional-hazard regression was used to investigate associations of variables with overall survival (OS: from time of diagnosis to death or last follow-up). Results: Demographic and CT details are provided (Table). The median age at diagnosis was 34.5 yrs (range: 9-71). The most common MPNST location was the trunk (56.94%). D based regimens were the most frequent 1st-line CT (65.7%), and gemcitabine- docetaxel was the most frequent 2nd-line CT (33.3%). In pts with metastases, 74.4% got 1st line, 44.7% 2nd line, 25.5% 3rd line, and 12.7% got 4th line therapy. Median follow-up was 2.46 yrs (IQR 1.24-9.52). The median time on treatment for 1st and 2nd line CT was 110 (IQR 48-153) and 57 (IQR 41-133) days, respectively. In the multivariate COX model for the entire cohort, male sex (HR: 0.35, 95%CI: 0.18-0.68), lower extremity primary (HR: 0.09, 95%CI: 0.02-0.40), and absence of metastases at last follow up (HR: 0.05, 95%CI: 0.02-0.17) were associated with decreased risk of death. Additional analysis on efficacy and survival of the systemic therapy regimens will be presented at the meeting. Conclusions: In this study < 50% pts with advanced NF1 related MPNST made it to 2nd line CT and outcomes were inferior to the predominantly D based 1st line regimens. This highlights an area of high unmet need. [Table: see text]

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.

Epidemiological trends and socioeconomic factors in malignant peripheral nerve sheath tumors with rhabdomyoblastic differentiation: A National Cancer Database study.

e23562 Background: Malignant peripheral nerve sheath tumor with rhabdomyoblastic differentiation, also called a malignant triton tumor (MTT) is both a rare and aggressive form of cancer with both the features of peripheral nerve sheath tumors as well as rhabdomyoblasts with high recurrence rates. There is a higher risk of patients with neurofibromatosis type 1 (NF1) developing MTT. Radiation can be used to excise higher grade large MTT, however, chemotherapy still has no consensus on efficacy. Despite the rarity of MTT with rhabdomyoblastic differentiation, increased efforts to understand epidemiological trends could increase overall understanding of the malignancy. Methods: We extracted data from 50 patients diagnosed with MTT(ICD-9561-3) using the 2004-2020 National Cancer Database (NCDB) to perform a retrospective cohort analysis. We focused on various demographic factors including age, sex, race, Hispanic status, income status, educational status, insurance status, facility type and location, distance from facility, and Charleson-Deyo score using descriptive statistics. Regression analysis was used to identify incidence trends. Results: In our study of 50 patients diagnosed with MTT, a majority of the patients were male (62%), identified as White, and were of non-Spanish/non-Hispanic (90%) ethnicity. The average age at diagnosis was 49 years (SD = 20, range = 3-90) most and patients were treated in academic/research facilities (32%) or integrated network cancer programs (18%). Most patients (48%) had private insurance, with a significant number relying on government-funded programs (44%). The majority of patients (88%) underwent surgery as their primary treatment, with 30% having no residual tumor post-surgery. Additional treatments included radiation therapy (38%), chemotherapy (34%) and the most frequent primary site was the retroperitoneum (30%).The average survival time post-treatment was 35 months, with a survival rate of 43% at 2 years, 23% at 5 years, and a 15% at 10 years. Patients qualified for the top quartile of median housing income( $74,063 ≈). Conclusions: This study is the first analysis of patients with MTT, using the NCDB. It fills a gap in our understanding of this rare and aggressive disease. The majority of MTT patients were male, Caucasian, with an average age at diagnosis of 49 years, which supports previous case report descriptions. In addition, this study reveals the socio-economic factors associated with these patients who mostly earned a median income of $74,063 or more, were insured primarily by private insurance or managed programs (48%), and were treated predominantly in academic or research institutions (32%). It is necessary to continue research to further understand the influence of demographic and socio-economic factors on the diagnosis, treatments, and overall survival of patients with MTT.

The efficacy of immune checkpoint inhibitors as a part of multimodality treatment in soft tissue and bone sarcoma in an academic community setting.

e23564 Background: Prior studies have shown response to immune checkpoint inhibitors (ICI) in a variety of sarcoma subtypes, however, much is still unknown about ICI use in specific sarcoma subtypes due to disease rarity. Patients (pts) are often treated with these agents as part of clinical trials, and real world data in the community setting is lacking. The aim of this study is to report real world efficacy and safety of ICI in sarcoma either alone or with radiation (RT) and/or surgery. Methods: A retrospective cohort review was conducted to identify pts with soft tissue and bone sarcoma who were administered ICI at Kellogg Cancer Center at NorthShore University HealthSystem/Endeavor Health. Pts who received ICI as part of a clinical trial were excluded. Results: A total of 29 pts receiving ICI were identified. Pts had a median of 1 prior systemic therapy. ICI included pembrolizumab (n = 23), nivolumab (n = 5), and ipilimumab/nivolumab (n = 1). Treatment was discontinued in 28 pts due to disease progression (n = 18), toxicities (n = 3), death (n = 2), and maximal response (n = 5). One patient is still undergoing treatment. Median progression-free survival (PFS) was 4.9 months. Median overall survival (OS) was 14 months. Overall response rate (ORR) is 31%. Median duration of response was not reached (44+ months). Complete response (CR) (n = 5) reported in 3 pts with undifferentiated pleomorphic sarcoma (UPS), 1 pt with SMARCA4 deficient undifferentiated sarcoma, and 1 pt with dedifferentiated chondrosarcoma. Partial response (PR) (n = 4) reported in 1 pt with UPS, 1 pt with dedifferentiated liposarcoma, 1 pt with high grade spindle sarcoma of bone, and 1 pt with malignant peripheral nerve sheath tumor. Of those pts with a CR, 2 patients received only pembrolizumab, 1 pt was administered concomitant RT, and 2 pts had administered concomitant surgery. Of the pts who had PR, 3 were also treated with concomitant RT. Grade 3 immune related adverse effects were reported in 5 of the 29 patients. Of these patients, 2 had documented CR and 3 documented PR. Conclusions: This study expands on the real world efficacy of ICI in a variety of sarcoma subtypes. CR and PR rates in this setting were high, and responses were durable, although selection bias for treatment may have played a role. This data supports the treatment of metastatic sarcoma with ICI, especially with concomitant RT and surgery, in a variety of subtypes.

Schwannomas: Experience from a single center reference in Peru.

e14043 Background: Schwannomas are nerve sheath tumors that originate in Schwann cells. They are usually solitary and sporadic and manifest on peripheral, spinal or cranial nerves. It is the most common type of benign peripheral nerve tumor in adults. These tumors represent a diagnostic challenge due to their rarity and difficult differential diagnosis. Our objective was to determine the clinical and pathological characteristics, as well as the therapeutic management of patients with Schwannoma admitted to our institution over a period of time. Methods: A retrospective, cross-sectional and descriptive study was carried out on the cases of patients with Schwannoma over 14 years of age, diagnosed at the National Institute of Neoplastic Diseases from 2009 to 2023. Medical records and pathology reports were reviewed. Results: A total of 225 patients were diagnosed with schwannoma on anatomopathology. Median age was 44 years, with a range of 15 to 92 years. 135 (60%) patients were female and 90 (40%) male, with a ratio of 1.5:1. 19 (8.4%) patients had a second cancer before or after the diagnosis of schwannoma. 6 (2.66%) patients were previously diagnosed with neurofibromatosis. According to anatomical origin: 27 (12%) patients had schwanommas of the abdominal region, 36 (16%) of the head and neck, 42 (18.66%) of the spinal cord, 17 (7.55%) of the extremities, 83 ( 36.88%) of the intracranial region and 20 (8.88%) of the thorax. At the intracranial level, 71 patients had location at the cerebellopontine angle, 5 at the orbital level, 2 at the level of the cerebellum and 5 in another location. At the abdominal level, 13 patients had a retroperitoneal location, 8 at the gastric level, 2 at the renal level and 4 in another location. In 130 patients we can obtain the ki67, median score was 2% (1-50%). Regarding treatment, 156 (69.33%) patients underwent surgery, and 42 (18.66%) patients received radiation treatment. During their follow-up, only 5 (2.22%) patients had local recurrence. Conclusions: Schwannomas are rare benign tumors. In many cases, its suspected diagnosis is difficult due to its similarity to other tumors that must be part of the differential diagnosis. Its treatment is surgical, with the objective of complete macroscopic resection. Radiotherapy is a complementary treatment in case of residual disease.

A Case of Giant Malignant Peripheral Nerve Sheath Tumor of Neck

Malignant peripheral nerve sheath tumor (MPNST) is an extremely rare sarcoma of soft tissue. It is locally invasive, frequently recurred and metastasizes distantly, therefore has a very poor prognosis. the most involved sites are human body and extremities, and MPNST occurs and involved very rarely in the parapharynx of neck. MPNST does not react to radiotherapy and chemotherapy, therefore complete surgical resection is the most important treatment. Since immunohistochemical staining is essential for the final diagnosis, it is common to be confirmed after surgery. We report a case of giant MPNST without symptom in the head and neck involving the right parapharynx with multiple distant metastases in a 74-year-old patient on a review of the literature.

Malignant melanotic schwannoma of the cervical spinal cord: a case report

Spinal cord malignant melanotic schwannoma (MMNST) is a rare central nervous system tumor that originates from the spinal cord or spinal myelin sheath cells and can produce melanin. This type of tumor is usually highly aggressive and malignant, with a poor prognosis. The clinical manifestations of spinal cord MMNST are mainly pain, paresthesia, muscle weakness, muscle atrophy, etc., and symptoms of spinal cord compression, such as intestinal and bladder dysfunction, paraplegia, etc. Early detection of tumor lesions can facilitate tumor removal, improve patients’ quality of life, and prolong patients’ survival. In this case report, a 27-year-old young woman was diagnosed with MMNST of the cervical spinal cord due to weakness of her limbs in our hospital, and underwent surgical resection. The patient’s limbs returned to normal after surgery. It is worth mentioning that the patient visited our hospital 7 months ago for “right upper limb pain for 3 days” and was diagnosed with a cervical spine space-occupying lesion at the same position this time, but the pathology report was “hemosiderosis”. This case report aims to raise awareness of the problem of spinal cord MMNST and contribute to greater knowledge of this rare tumor.

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.

Surgical outcome of isolated benign peripheral nerve sheath tumors without neurofibromatosis

BackgroundBenign peripheral nerve sheath tumors (BPNSTs) include schwannomas and neurofibromas. About 10% of soft tissue sarcomas are malignant peripheral nerve sheath tumors (MPNSTs), which are invasive and aggressive tumors. These can happen occasionally or after radiation exposure. Up to 90% of schwannomas are made up of differentiated neoplastic Schwann cells. Malignant transformation of schwannomas is rare.MethodsWe collected the medical records of all patients (including their family histories), performed comprehensive physical and neurological assessments, and checked for the presence of a Tinel-like sign, as well as screening for neurofibromatosis (NF) signs. Magnetic resonance imaging (MRI), nerve conduction studies, and ultrasound were done for all cases.ResultsWe have operated on 21 patients with age range 29–52 years. The mean age was 39.4 years. 14 of these patients were females and 7 were males. The presenting symptoms were just swelling at nerve site in 14 patients, spontaneous pain at the nerve sites in 7 patients, and sensory deficit at the nerve distribution sites in 9 patients. The other 12 patients were sensory intact and only 7 patients had motor deficit. Postoperatively all patients had improved motor and sensory deficit and none of intact patients were worsened. Preoperatively we did MRI to show important nearby vascular structure anatomical abnormalities and we ordered nerve studies to all patients that showed abnormalities, which was only in 9 patients. Gross total resection was done in 18 patients and other 3 cases had partial resection to avoid sensory and motor deficits. The pathological analysis revealed 11 schwannomas and 10 neurofibromas. With 1 year follow up there was no recurrence in any patients.ConclusionBenign pheripheral nerve sheath tumours are safely resected without increased sensory and motor deficits after surgery and with improve clinical outcome with no recurrence on follow up.

PET Imaging of Neurofibromatosis Type 1 with a Fluorine-18 Labeled Tryptophan Radiotracer.

Neurofibromatosis type 1 (NF1) is a neurocutaneous disorder. Plexiform neurofibromas (PNFs) are benign tumors commonly formed in patients with NF1. PNFs have a high incidence of developing into malignant peripheral nerve sheath tumors (MPNSTs) with a 5-year survival rate of only 30%. Therefore, the accurate diagnosis and differentiation of MPNSTs from benign PNFs are critical to patient management. We studied a fluorine-18 labeled tryptophan positron emission tomography (PET) radiotracer, 1-(2-[18F]fluoroethyl)-L-tryptophan (L-[18F]FETrp), to detect NF1-associated tumors in an animal model. An ex vivo biodistribution study of L-[18F]FETrp showed a similar tracer distribution and kinetics between the wild-type and triple mutant mice with the highest uptake in the pancreas. Bone uptake was stable. Brain uptake was low during the 90-min uptake period. Static PET imaging at 60 min post-injection showed L-[18F]FETrp had a comparable tumor uptake with [1⁸F]fluorodeoxyglucose (FDG). However, L-[18F]FETrp showed a significantly higher tumor-to-brain ratio than FDG (n = 4, p < 0.05). Sixty-minute-long dynamic PET scans using the two radiotracers showed similar kidney, liver, and lung kinetics. A dysregulated tryptophan metabolism in NF1 mice was further confirmed using immunohistostaining. L-[18F]FETrp is warranted to further investigate differentiating malignant NF1 tumors from benign PNFs. The study may reveal the tryptophan-kynurenine pathway as a therapeutic target for treating NF1.

Evaluating the Efficacy of Volume Isotropic Turbo Spin Echo Acquisition Versus T2-Weighted Turbo Spin Echo Imaging in the Diagnosis of Nerve Root and Perineuronal Pathologies in Spinal Disorders.

Background While two-dimensional (2D) turbo spin echo (TSE) sequences offer better through-plane resolution than three-dimensional (3D) isotropic TSE sequences images, with a narrower thickness of the slice, 3D isotropic TSE sequences are known to have a weaker in-plane resolution as well as blurring of the image. These elements may make it more difficult to distinguish between nearby structures that may affect nerve roots and small nerve roots during spinal imaging. This study aimedto analyze the accuracy of T2 TSE sequence and volumetric isotropic TSE acquisition in determining the indentation of nerve roots and perineural diseases such as nerve sheath tumors and Tarlov cysts. Methods Fifty patients who attended the Department of Radiodiagnosis for magnetic resonance (MR) spine participated in this prospective study. Routine MR lumbosacral (LS) spine sequences, such as survey, coronal T2short-tau inversion recovery (STIR), sagittal T2 TSE, sagittal T1 TSE, and axial T2 TSE, were carried out after a localizer was acquired. More sequences from volume isotropic turbo spin echo acquisition (VISTA) were acquired. For both 2D and 3D sequences, the visibility ratings for perineural cysts, spinal canal stenosis, and nerve root indentation were evaluated. Visibility ratings ranged from zero to four. Results In the cases of perineural cyst, spinal canal stenosis, and nerve root impingement, the mean difference between the VISTA and T2 TSE visibility scores was 0.04, 0.54, and 0.56, respectively. The VISTA and T2 TS had standard deviation differences of 0.006, 0.026, and 0.06, respectively. The "t" values for nerve root impingement, spinal canal stenosis, and perineural cysts were, in order, 50, 180, and 70. Because the p-value was <0.01, a statistically significant variation has been observed. Conclusion In the diagnosis of neural and perineuronal disorders, the visibility scores for 3D T2 TSE (VISTA) were considerably better than those for 2D T2 TSE in identifying perineural cysts, spinal canal stenosis, and nerve root indentation.

Imaging characteristics and diagnosis of primary middle mediastinal tumors

Objectives: To investigate the proportion of different histological types and CT enhanced imaging features of primary middle mediastinal lesions in order to improve the understanding of these tumors and the accuracy of preoperative diagnosis. Methods: Retrospective analysis was conducted on 84 patients with primary middle mediastinal lesions and clear histological classifications diagnosed and treated at the Cancer Hospital, Chinese Academy of Medical Sciences from January 2012 to December 2022. Clinical, imaging, and pathological data were collected and classified according to tumor histological classifications. CT imaging manifestations such as tumor location, size, morphology, edge, boundary, internal components, enhancement characteristics, and surrounding tissue invasion were evaluated and recorded. Results: The histological types of the primary middle mediastinal lesions from the 84 patients included mesenchymal tumors, anterior intestinal cysts, giant lymph node hyperplasia, substernal goiter, neuroendocrine carcinoma, lymphohematopoietic system tumors, and mesothelioma, accounting for 28.6%, 27.4%, 14.3%, 3.6%, 11.9%, 9.5%, and 4.8%, respectively. Mesenchymal tumors included peripheral nerve sheath tumors, vascular tumors, adipogenic tumors, solitary fibrous tumors, and synovial sarcoma, accounting for 54.2%, 20.8%, 12.5%, 8.3%, and 4.2%, respectively. The above tumors had diverse imaging manifestations and specific imaging features. Mature fat were found in 3 cases of liposarcoma; Calcification was observed in 2 cases of thyroid nodules and 7 cases of giant lymph node hyperplasia; Enhanced scanning showed significant enhancement in 2 cases of solitary fibrous tumors, 3 cases of thyroid nodules, and 11 cases of giant lymph node hyperplasia; Mediastinal large lymph nodes was observed in 6 cases of lymphoma and 3 cases of mesothelioma; High invasiveness was observed in 4 cases of mesothelioma and 9 cases of neuroendocrine carcinoma. Conclusion: Mediastinal tumors have low incidence rate and rich histological types, and their imaging manifestations are diverse. Preoperative differential diagnosis can be made according to their specific imaging characteristics.

The functional and clinical outcomes of primary and metastatic malignancies of the elbow.

This study aims to investigate the etiological distribution of primary and metastatic malignancies around the elbow and the effect of surgical and adjuvant treatments on clinical outcome. Between January 2006 and December 2020, medical records of a total of 33 patients with elbow neoplasm (15 males, 18 females; median age: 55 years; range, 39 to 71 years) who underwent surgical treatment and with or without clinical treatment were retrospectively analyzed. The outcomes and frequencies of the elbow metastatic and primary malignancies were evaluated. Data were collected from patients' medical and radiological documents, and a dedicated archive was created for this study. Most tumors occurred on the right side and were intra-articular or distal to the humerus. A total of 75.8% (25/33) of the patients had tumors of any diameter ≥5 cm. Most patients were treated with extensive resection. A total of 81.8% (27/33) of the patients had wide resected tumor margins, and 18.2% (6/33) had intralesional tumor margins. The median follow-up was 42 (range, 1 to 83) months. Synovial sarcoma and malignant peripheral nerve sheath tumors were the most common soft tissue sarcomas, and pulmonary adenoma and multiple myeloma were found in metastatic lesions. Elbow surgery is particularly challenging due to the interrelationship of major neurovascular structures. Synovial sarcoma and malignant peripheral nerve sheath tumors are the most common soft tissue sarcomas, and pulmonary adenoma and multiple myeloma are found in metastatic lesions. Limb-sparing surgery is the gold-standard method recently.

Identifying, Diagnosing, and Grading Malignant Peripheral Nerve Sheath Tumors in Genetically Engineered Mouse Models.

Patients with the autosomal dominant tumor susceptibility syndrome neurofibromatosis type 1 (NF1) commonly develop plexiform neurofibromas (PNs) that subsequently transform into highly aggressive malignant peripheral nerve sheath tumors (MPNSTs). Understanding the process by which a PN transforms into an MPNST would be facilitated by the availability of genetically engineered mouse (GEM) models that accurately replicate the PN-MPNST progression seen in humans with NF1. Unfortunately, GEM models with Nf1 ablation do not fully recapitulate this process. This led us to develop P0-GGFβ3 mice, a GEM model in which overexpression of the Schwann cell mitogen neuregulin-1 (NRG1) in Schwann cells results in the development of PNs that progress to become MPNSTs with high frequency. However, to determine whether tumorigenesis and neoplastic progression in P0-GGFβ3 mice accurately model the processes seen in NF1 patients, we had to first prove that the pathology of P0-GGFβ3 peripheral nerve sheath tumors recapitulates the pathology of their human counterparts. Here, we describe the specialized methodologies used to accurately diagnose and grade peripheral nervous system neoplasms in GEM models, using P0-GGFβ3 and P0-GGFβ3;Trp53+/- mice as an example. We describe the histologic, immunohistochemical, and histochemical methods used to diagnose PNs and MPNSTs, how to distinguish these neoplasms from other tumor types that mimic their pathology, and how to grade these neoplasms. We discuss the establishment of early-passage cultures from GEM MPNSTs, how to characterize these cultures using immunocytochemistry, and how to verify their tumorigenicity by establishing allografts. Collectively, these techniques characterize the pathology of PNs and MPNSTs that arise in GEM models and critically compare the pathology of these murine tumors to their human counterparts.

Malignant Tumor of the Sheaths and Peripheral Nerves: A Case Report

Malignant Peripheral Nerve Sheath Tumors (MPNST) are a rare anatomopathological subtype of soft tissue sarcoma. We report a case of MPNST in a patient without a history of neurofibromatosis. He presented with a progressively developing ulcerobourgennate lesion on the left buttock. Histopathological analysis of a biopsy of the mass confirmed MPNST. These are rare tumors that can occur in patients without any particular history and are difficult to manage at an advanced stage.

Clinical characteristics and prognosis of patients with incidentally discovered chest wall sarcoma compared with those of symptomatic patients.

Sarcomas of the bone and soft tissues are detected after the onset of pain, detectable mass and related symptoms in the absence of a standardized screening examination. However, primary chest wall sarcomas can be incidentally detected upon chest X-ray or computed tomography. Previous studies of incidental primary chest wall sarcomas lack prognosis and disease-specific clinical data. This study aimed to investigate the prognoses of patients with incidental chest wall sarcomas and compare them with those of symptomatic patients. This study included 18 patients diagnosed with primary chest wall sarcoma between 2010 and 2023. Patient information such as age, sex, tumour diameter, tumour location, symptoms, treatment, time to treatment initiation, pathological diagnosis and outcome were retrospectively analysed. Among the 18 patients, the sarcomas were incidentally detected in five by chest X-ray and computed tomography in three and two patients, respectively. The pathological diagnoses of the patients were Ewing sarcoma, Chondrosarcoma grade 1, grade 2, periosteal osteosarcoma and malignant peripheral nerve sheath tumour. The patients had no symptoms at the first visit to our hospital, and no lesions in other organs were detected at the time of the initial examination. At the final follow-up, the patients remained disease-free after radical treatment. The tumour sizes of the five patients were significantly smaller than those of patients with symptoms (P=0.003). The incidental detection of chest wall sarcomas and consequent early detection and treatment of tumours improves patient prognosis relative to that of symptomatically diagnosed patients.

Integrated Epigenetic and Transcriptomic Analysis Identifies Interleukin 17 DNA Methylation Signature of Malignant Peripheral Nerve Sheath Tumor Progression and Metastasis.

Sarcomas are a complex group of highly aggressive and metastatic tumors with over 100 distinct subtypes. Because of their diversity and rarity, it is challenging to generate multisarcoma signatures that are predictive of patient outcomes. Here, we identify a DNA methylation signature for progression and metastasis of numerous sarcoma subtypes using multiple epigenetic and genomic patient data sets. Malignant Peripheral Nerve Sheath Tumors (MPNSTs) are highly metastatic sarcomas with frequent loss of the histone methyltransferase, PRC2. Loss of PRC2 is associated with MPNST metastasis and plays a critical noncanonical role in DNA methylation. We found that over 900 5'-C-phosphate-G-3' (CpGs) were hypermethylated in MPNSTs with PRC2 loss. Furthermore, we identified eight differentially methylated CpGs in the IL17D/RD family that correlate with the progression and metastasis of MPNSTs in two independent patient data sets. Similar trends were identified in other sarcoma subtypes, including osteosarcoma, rhabdomyosarcoma, and synovial sarcoma. Analysis of scRNAseq data sets determined that IL17D/RD expression occurs in both the tumor cells and the surrounding stromal populations. These results might have broad implications for the clinical management and surveillance of sarcoma.

Low-grade malignant peripheral nerve sheath tumour presenting as retroperitoneal spindle cell neoplasm.

Retroperitoneal spindle cell neoplasms are diagnostically challenging. Malignant peripheral nerve sheath tumours (MPNSTs) can sometimes present as sporadic primary retroperitoneal tumours. MPNSTs are usually high-grade and highly aggressive tumours and are associated with a poor prognosis. Low-grade MPNSTs are very rarely described. This current case report describes a case of sporadic primary low-grade MPNST presenting as retroperitoneal spindle cell neoplasm. The diagnosis, imaging and immunohistopathological findings, as well as its successful surgical management, are presented.