Nerve Sheath Tumors Research Articles

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.

Robotic thoracic surgery for neurogenic tumors.

Thoracic neurogenic tumors usually present as benign nerve sheath tumors that can be resected via transthoracic or posterior approaches, depending on the anatomical location. Robot-assisted thoracic surgery (RATS) is increasingly being used for the transthoracic approach, but evidence is very limited. The authors initiated the current study to evaluate the efficacy and safety of RATS for thoracic neurogenic tumors. This retrospective study is based on a prospectively created database that includes all RATS surgeries between 2018 and 2023. All patients with histologically confirmed neurogenic tumors were included in the study. The patients' medical and surgical records as well as radiological and pathological findings were analyzed. During a 5-year period, 27 patients underwent robotic resection of neurogenic tumors at a high-volume thoracic surgery center. Two patients had previously undergone posterior laminectomy for resection of the intraspinal components. The pathologies included schwannomas (18, 64%), ganglioneuromas (8, 29%), 1 paraganglioma, and 1 neurofibroma occurring close to a schwannoma unilaterally in the same patient. The median tumor size was 4.7 cm (range 0.9-11.4 cm). The median operating time was 69 minutes (range 27-169 minutes), and the median postoperative stay was 3 days (range 1-19 days). There was one conversion due to adhesions after a previous surgery. No major bleeding occurred. There was no perioperative mortality. Morbidity included a lymphatic fistula (n = 1), pneumonia (n = 1), prolonged air leak (n = 1), and 4 cases of postoperative pain persisting for more than 4 weeks. Neurological complications were mostly observed in patients with tumors located at the thoracic apex: 2 cases of Horner's syndrome, 2 cases with compensatory hyperhidrosis, 1 patient with paresis of the recurrent laryngeal nerve, and a T1 lesion resulting in a minor motor deficit of the small hand muscles (Medical Research Council grade 4) and hypoesthesia of the respective dermatome. RATS for thoracic neurogenic tumors is feasible and safe. Tumors at the thoracic apex are at high risk of neurological deficit and should be approached with care. Close interdisciplinary collaboration between neurosurgeons and thoracic surgeons is necessary for optimal patient selection and a good postoperative outcome.

Analysis of the effect of different facial nerve managements applied to tumor resection in the jugular foramen region

Objective:To summarize the results of different facial nerve management modalities applied to tumor resection in the jugular foramen region. Methods:The clinical data of 54 patients with tumors in the jugular foramen region who underwent surgery from January 2015 to March 2023 were retrospectively analyzed: 18 males and 36 females; Age ranges from 21 to 67 years, with an average age of 44.4 years; and median follow-up time: 12 months. The House-Brackmann（HB） grading system was applied to assess the patients' facial nerve function before surgery, 1-2 weeks after surgery and at the final follow-up （HBⅠ-Ⅱ grade for good function）: 42 cases with preoperative HB grades Ⅰ-Ⅱ; partial facial nerve transposition（9 cases）, complete facial nerve transposition（28 cases）, and facial nerve excision and re-construction（17 cases） were used, respectively（stage Ⅰor Ⅱ）. Relevant factors affecting postoperative facial nerve function were analyzed. Results:Postoperative pathology confirmed 39 cases of paraganglioma, 9 cases of nerve sheath tumor, 3 cases of meningioma, and 1 case each of fibromucinous sarcoma, chondrosarcoma, and intravascular myofibroma. Facial nerve function after partial facial nerve transposition was HB grade Ⅰ-Ⅱ in 89%（8/9）; after complete facial nerve transposition was HB grade Ⅰ-Ⅱ in 86%（24/28） in 28 cases; after facial nerve severance and reconstruction was HB grade Ⅰ-Ⅱ in 2/7（Stage Ⅰ） and 0/3（Stage Ⅱ）, respectively. Tumor size and surgical approach were correlated with postoperative facial nerve function in patients with facial nerve transposition（P<0.05）. There was no statistically significant difference in facial nerve function after complete and partial facial nerve transposition（P>0.05）. Conclusion:Intraoperative stretching of the facial nerve may be an important factor affecting facial nerve function during surgical treatment of tumors in the jugular venous foramen region; for patients with facial nerve dissection, facial nerve reconstruction should be adopted according to the situation, aiming at the recovery of facial nerve function.

Degenerated (Ancient) Schwannomas: Unraveling Unusual Locations and Treatment Management

Background/Aims:Schwannomas, originating from Schwann cells in peripheral nerve sheaths, exhibit diverse clinical manifestations and unpredictable behavior. Among them, ancient schwannomas, with distinctive degenerative features, present in atypical locations and pose diagnostic challenges. This study explores their unique characteristics and implications for diagnosis and management. Material and Methods: The study was designed as a retrospective analysis of 7 adult patients aged ≥18 years, diagnosed with paraspinal, presacral, sacral, or para-aortic tumors, all confirmed histologically as ancient schwannomas. Data for analysis were collected from patients treated and followed up at Ankara City Hospital between April 2017 and December 2022. Ethical approval and informed consent were obtained before inclusion in the study. Results: The most common symptoms included the presence of a local lump (71,4%) and localized or radiating pain (57,1%). Notably, 1 patient (14,2%) was incidentally diagnosed during the evaluation process. Surgical intervention played a crucial role in the management of these tumors, with 71,4% of patients undergoing complete resection, while 28,5% underwent subtotal resection. Tumor recurrence occurred in 42,8% of cases, prompting the administration of radiotherapy as part of the treatment strategy. Imaging findings, particularly on MRI, played a crucial role in the accurate identification of ancient schwannomas. These tumors displayed isointensity on T1-weighted images and heterogeneous hyperintensity on T2-weighted images, along with distinctive heterogeneous contrast enhancement. Conclusion: Ancient schwannomas exhibit unique histological features and distinctive MRI characteristics, differentiating them from other nerve sheath tumors. Early diagnosis and complete surgical resection offer favorable outcomes. Awareness of this entity is essential for managing peripheral nerve sheath tumors effectively.

Multiple spinal schwannomas of multiple intradural extramedullary tumors: a case report

We describe the case of a 30-year-old male patient who was brought to the hospital's general surgery department with a four-month history of low back pain, numbness, and paraesthesia in both legs, history of weakness in both legs is also present. Magnetic resonance imaging revealed multiple Intradural extramedullary tumors at the C3/C4, D1-D2, D4, and D8 levels- likely nerve sheath tumors (schwannomas). The patient underwent surgery for the removal of tumors. The diagnosis was validated by histopathological examination. Post-operative recovery was uneventful and the patient improved gradually and recovered fully in 10-15 days.

Neglected very large ancient schwannoma of the distal wrist: a case report and literature review

Ancient schwannoma is a variant of schwannoma characterized by slow progression, degenerative changes, and a higher incidence in older adults. There have been two prior reported cases of ancient schwannoma arising from the distal ulnar nerve at the wrist level, but neither were longstanding or very large. Herein, we report an ancient schwannoma found in the ulnar nerve of the distal forearm that was found to be clinically meaningful in size. A 61-year-old man presented with complaints of tingling sensation of the fourth and fifth fingers and bulging of the ulnar side of the wrist. The patient reported that the mass in his wrist had grown very slowly, starting about 10 years ago, and that he had started experiencing a tingling sensation in his fourth and fifth fingers about 3 years prior, which had become worse in the past year. Based on the results of the preoperative examination, a benign nerve sheath tumor was suspected. As it was thought that the possibility of malignancy was not high, we elected to perform a marginal excision. Pathological examination confirmed ancient schwannoma. At his most recent visit, 3 years after surgery, he reported no recurrence and that he felt better than before surgery, but some tingling sensations remained. As with small ancient schwannoma in the distal wrist, most cases of large ancient schwannoma can be treated without special complications based on an accurate preoperative diagnosis.

Clinical Findings and Outcome in 30 Dogs with Presumptive or Confirmed Nerve Sheath Tumors.

Nerve sheath tumors (NSTs) are well-recognized primary nervous system tumors, but there is relatively limited information in dogs including comparison of NSTs in different anatomical locations. This retrospective study describes the clinical features and outcomes in a group of dogs with NSTs affecting the cranial nerves or spinal nerves. Thirty dogs were included, 25 with a presumptive diagnosis and five confirmed by histopathologic analysis. Seven dogs also had cytology of tumor samples, which were supportive of the NST diagnosis in four. Eight dogs had cranial nerve-associated NSTs, with six involving the trigeminal nerve. Twenty-two dogs had spinal nerve-associated NSTs including 13 invading the spinal canal and nine peripheral to the spinal canal, with the majority affecting nerves or nerve roots of the brachial plexus. The prognosis was poor, with dogs being euthanized eventually because of disease progression. Among dogs alive 1 week after diagnosis, the median survival time was 4 months but ranged from 2 weeks to >2 years. While there was a broad overlap between NST locations, survival was generally longer for dogs without spinal canal or intracranial involvement. The results expand available information on NSTs in dogs but should be interpreted with caution given the small number of dogs with a definitive diagnosis. Further investigation is warranted to determine how tumor location, invasiveness, and treatments pursued impact outcome.

Malignant Nerve Sheath Tumour - A Case Report.

Malignant nerve sheath tumors are rare and aggressive soft tissue sarcomas. They contribute to 5-10% of all soft tissue sarcomas. They can be sporadic, occur in patients with NF1 (neurofibromatosis 1) or can occur after radiation therapy. A high rate of recurrence and hematogenous metastasis is seen in these patients. They are also associated with poor prognosis. A case of malignant nerve sheath tumor seen in a 44-year-old male with pre-existing NF1 is being discussed here due to the unique nature of the disease and its rarity.

Neurilemmoma at the Junction of Hard and Soft Palate: A Case Report

Neurilemmoma is a benign peripheral nerve sheath tumour arising from schwann cells. It is relatively uncommon; around 25% to 48% of all cases occur in the Head and Neck region. Only 1% occur in the oral cavity and tongue being the most common site. Here, we report a case of a 40-year-old female patient with swelling in the junction of the hard and soft palate on the left side for 15 years. Due to its duration, site, and nature, it mimicked a glandular neoplasm. Clinical, histopathological, and immunohistochemical findings confirmed it as a neural tumour -Neurilemmoma.

Sarcoma incidence worldwide: regional differences in histology and molecular subtypes.

There are numerous sarcoma subtypes and vary widely in terms of epidemiology, clinical characteristics, genetic profiles, and pathophysiology. They also differ widely between ethnic groups. This review focuses on the different incidence rates of sarcomas in different regions and the potential explanations for these disparities. In an intercontinental study using national cancer registry databases from France and Taiwan, the French population had a higher risk of liposarcomas, leiomyosarcomas, and synovial sarcomas, whereas the Taiwanese population had a higher incidence of angiosarcomas and malignant peripheral nerve sheath tumors. The anatomical distribution of these sarcomas also varied between these two regions. In France, most angiosarcoma cases occurred in the extremities and trunk, whereas in Taiwan, angiosarcoma cases in the abdomen and pelvis were more common. Another international study showed that in addition to the common known TP53 and NF1 germline mutations, genes involved in centromere and telomere maintenance were also involved in sarcomagenesis. We reviewed factors related to genetics, environmental effects, chemical exposure, and radiation exposure that could explain the differences in sarcoma incidence among different geographical or ethnic regions. Our understanding of the potential cause of sarcomas with different subtypes is limited. Establishing a comprehensive global database for patients with sarcomas from all ethnic groups is essential to deepen our understanding of the potential risk factors and the pathophysiology of all sarcoma subtypes.