[Successful surgical excision of a melanoma and a rare peripheral nerve sheath tumor in 2 cattle]. / Erfolgreiche chirurgische Exzision eines Melanoms und eines seltenen peripheren Nervenscheidentumors bei 2 Rindern.

A heifer and a dairy cow were presented to our practice with cutaneous masses on the left side of their necks. Each mass had a diameter of approximately 20 cm. Both tumors had increased in size in recent weeks and were now prone to injuries from the stable equipment. Both animal owners agreed to surgical removal, which was performed under sedation and local anesthesia on a bovine treatment crush. The subsequent histopathological examinations of the extirpates revealed a melanocytoma in the young heifer and a cutaneous peripheral nerve sheath tumor (PNST) in the dairy cow. Both cases were benign tumors. The postoperative course was without complications and no recurrences were observed even more than a year later. No comparable tumors were found in related animals or in the offspring.

Incidental finding of Psuedomyxoma Peritonei in Malignant Peripheral Nerve Sheath Tumour.

Psuedomyxoma peritonei is an infrequent clinical entity characterised by intraperitoneal mucinous/gelatinous ascites produced by the cancerous cells. It has been associated with gastrointestinal, gynaecological, lung and breast tumours. It is commonly asymptomatic and is most often detected incidentally on abdominopelvic imaging or laparoscopy. Higher histological grade of the tumour shows increased metabolic activity on 18F-Fluorodeoxyglucose (FDG) positron-emission tomography (PET) computed tomography (CT). It has been rarely reported in patients with sarcoma. We hereby present an interesting case of incidentally diagnosed pseudomyxoma peritonei on 18FDG PET-CT scan of a patient with soft tissue sarcoma of peripheral nerve sheath.

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.

[Malignant melanotic nerve sheath tumor of the posterior mediastinum]. / Tumor maligno melanocítico de la vaina neural en mediastino posterior.

Melanotic schwannoma (MS) is a rare and infrequent subtype of schwannoma characterized by cytoplasmic deposits of melanosomes (melanin). Unlike the other schwannomas, it could have malignant transformation. Due to distinctive characteristics and atypical behavior from classic schwannomas subtypes, MS were renamed and reclassified as "melanocytic malignant neural sheath tumor" in the 5th ed. of the World Health Organization's classification of central nervous system tumors in 2021. We present two cases of MS that underwent complete surgical resection.

El schwannoma melanótico (SM) es una variante rara e infrecuente caracterizada por el depósito citoplasmático de melanosomas (melanina). A diferencia de las otras variantes de schwannomas, tienen capacidad de malignización. Por poseer características y comportamiento distintos al resto de los schwannomas, fue reclasificado como "tumor maligno melanocítico de la vaina neural" en la 5ta edición de la clasificación de los tumores del sistema nervioso central de la Organización Mundial de la Salud en 2021. Presentamos dos casos de SM de ubicación mediastinal en los que se realizó una resección quirúrgica completa.

A light in the darkness: sodium fluorescein-assisted peripheral nerve sheath tumors resection - a comprehensive systematic review and single-arm meta-analysis.

The treatment for peripheral nerve sheath tumors (PNSTs) is based on surgical excision and the primary goal is to improve symptoms whilst preserving neurological function. In order to improve this technique, surgeons may use sodium fluorescein (SF) to help visualize the neoplasm and, consequently, facilitate its removal. Aiming to assess the efficacy of this emerging surgical strategy, we conducted a systematic review and single-arm meta-analysis. We conducted a systematic search on the PubMed, Embase, and Web of Science databases, following the PRISMA guidelines. Studies without outcomes of interest, case series with less than four patients, letters, comments, technical notes, editorials, reviews, and basic research papers were excluded. The outcomes considered for this study were: the number of tumors that achieved total resection, subtotal resection, or near total resection, the approach/technique utilized by the surgeon, SF-related complications, and total complications. Five studies, with a total of 175 individuals, were included in our survey. Notably, 70% of the neoplasms presented by the patients were schwannomas. Considering extracranial lesions, we found a proportion of 96% (95% CI: 88 - 100%) in total resection, 0% (95% CI: 0-1%) in near total resection, and 4% (95% CI: 0-12%) in subtotal resection, all linked to an amount of 185 analyzed PNSTs. Furthermore, a proportion of 1% (95% CI: 0 - 2%) in SF-related complications was spotted among 183 patients. Finally, total complications analysis accounted for 11% (95% CI: 0 - 25%) among 183 individuals. We concluded that SF-assisted resection of PNSTs is a suitable and relatively safe technique, linked to minimum complications, of which the majority was not associated with the chemical compound itself. Future research is necessary to increase the number of patients available in the current literature and, therefore, enhance future analyses.

Bulky malignant peripheral nerve sheath tumour of the left thigh in a pregnant woman presenting with a pathological fracture of the proximal femur.

Malignant peripheral nerve sheath tumour (MPNST) is an aggressive soft tissue sarcoma with a poor prognosis, affecting most commonly the extremities. The lungs constitute the most frequent location for distant metastases. Half of all MPNSTs arise in patients with neurofibromatosis type 1, while approximately 10% are radiation induced and the rest are sporadic.The authors present a pregnant woman in her 40s with a sporadic MPNST of the lower limb and with lung metastases at diagnosis. Treatment consisted of interilioabdominal amputation, followed by adjuvant chemotherapy. Partial response and disease stabilisation were achieved with chemotherapy.Surgical resection with negative margins is the only potentially curative therapy, while radiation therapy and chemotherapy might be useful in the neoadjuvant or adjuvant setting, but their advantage in survival is not demonstrated. In the reported case, chemotherapy permitted the achievement of partial response and stabilisation of the disease.

An algorithmic approach to the management of peripheral nerve tumours.

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

[Interdisciplinary Treatment Of Tumorous And Tumour-Like Lesions Of Peripheral Nerves]. / Interdisziplinäre Behandlung von Raumforderungen in Assoziation zu peripheren Nerven: Tumore und tumorähnliche Läsionen.

Tumorous or tumour-like lesions of peripheral nerves are generally rare, heterogeneous and challenging to diagnose and treat. They may become apparent by a palpable swelling (lump) near nerves, sensory and/or motor deficits, pain to touch or neuropathic pain. In 91% of cases, tumours are benign. The differentiation of entities and their characteristics as well as a function-preserving resection strategy are highly relevant. Misdiagnosis and inadequate treatment can lead to severe deficits and pain syndromes. Benign tumours include schwannomas and neurofibromas, which can occur sporadically but can also be associated with neurogenetic tumour disposition syndromes if they occur more frequently. Rarer benign nerve tumours include perineuriomas, lipomas, aggressive fibrosis (desmoid tumours), paragangliomas and haemangiomas. Ganglion cysts are described as tumour-like lesions. The association of nerve tumours with neurogenetic syndromes and the correct classification of potentially malignant lesions such as MPNST (malignant peripheral nerve sheath tumour) or intermediate stages such as ANNUBPs (atypical neurofibromatous neoplasms with unknown biological potential) pose particular challenges. Interdisciplinarity is highly relevant for clinical treatment and a correct diagnosis. The aim of our work is to provide an overview of the relevant entities, diagnostic evaluation and contemporary treatment strategies based on the current data situation and taking into account the recently published interdisciplinary AWMF S2k guideline "Diagnosis and Treatment of Peripheral Nerve Tumours".

Intramuscular Hybrid Nerve Sheath Tumor of the Thigh: Case Report and Literature Review.

BACKGROUND/AIM: Hybrid nerve sheath tumor (HNST) is a benign peripheral nerve sheath tumor with combined features of more than one histological type, such as schwannoma, neurofibroma, and perineurioma. It remains under-recognized in routine clinical practice. Herein, we describe an unusual case of intramuscular HNST of the thigh. CASE REPORT: The patient was a 41-year-old man with no history of trauma who presented with a 3-month history of a palpable mass in the right thigh. Physical examination revealed a 4-cm, elastic hard, mobile, nontender mass. Magnetic resonance imaging exhibited a well-circumscribed intramuscular mass with low-to-intermediate signal intensity on T1-weighted sequences and higher signal intensity peripherally and lower signal intensity centrally, representing a target sign, on T2-weighted sequences. Complete surgical excision of the tumor was carried out. Microscopically, the tumor showed dual histological components of both schwannoma and neurofibroma. Immunohistochemically, the schwannomatous component was strongly and diffusely positive for S-100 protein and negative for CD34, while the neurofibromatous component contained CD34-positive fibroblasts and S-100 protein-positive Schwann cells. Epithelial membrane antigen was negative for both components. These findings were consistent with a diagnosis of HNST (hybrid schwannoma/neurofibroma). The patient had no evidence of local recurrence and no neurological deficit at the final follow-up. CONCLUSION: Although extremely rare, HNST should be included in the extended differential diagnosis of a well-circumscribed, intramuscular soft-tissue mass in the extremities, particularly in young and early middle-aged adults.

Surgical Treatment of Malignant Peripheral Nerve Sheath Tumor of the Scalp With Intracranial and Extracranial Extension: A Rare Case Report.

ABSTRACT: Malignant peripheral nerve sheath tumors of the scalp are rare neoplasms of the peripheral nervous system. Here, we describe an unusual malignant peripheral nerve sheath tumor of the scalp in an 84-year-old Asian man. The tumor was associated with bony destruction, intracranial, and extracranial extension. Trans-arterial embolization was done twice preoperatively. En block excision was performed and the dura and soft tissue defect were reconstructed by anterolateral thigh free fasciocutaneous flap. There is no recurrence and the wound healed well during follow-up.

A retrospective study on subcutaneous malignant peripheral nerve sheath tumors in 14 domestic rabbits (Oryctolagus cuniculus) treated surgically between 2008 and 2021.

A retrospective study involving 14 pet rabbits histopathologically diagnosed with malignant peripheral nerve sheath tumors (MPNSTs) was conducted. The age at diagnosis was 4-12 years, with a median age of 8.6 years. All rabbits had solid subcutaneous tumor masses in varied locations. Surgical excision of the tumors was performed in all cases. Recurrence was observed in 10 cases (71%), and postoperative metastasis to the lung was suspected in 4 cases (29%). The postoperative mean and median survival times were 11 months and 9 months, respectively. Hence, MPNSTs should be considered in the differential diagnosis for subcutaneous masses in rabbits and it is essential to inform the owners of the potentially high recurrence and metastasis rates.

Surgical management of malignant melanotic nerve sheath tumors: an institutional experience and systematic review of the literature.

OBJECTIVE: Malignant melanotic nerve sheath tumors are rare tumors characterized by neoplastic melanin-producing Schwann cells. In this study, the authors report their institution's experience in treating spinal and peripheral malignant melanotic nerve sheath tumors and compare their results with the literature. METHODS: Data were collected from 8 patients who underwent surgical treatment for malignant melanotic nerve sheath tumors between 1996 and 2023 at Mayo Clinic and 63 patients from the literature. Time-to-event analyses were performed for the combined group of 71 cases to evaluate the risk of recurrence, metastasis, and death based on tumor location and type of treatment received. Unpaired 2-sample t-tests and Fisher's exact tests were used to determine statistical significance between groups. RESULTS: Between 1996 and 2023, 8 patients with malignant melanotic nerve sheath tumors underwent surgery at the authors' institution, while 63 patients were identified in the literature. The authors' patients and those in the literature had the same mean age at diagnosis (43 years). At the authors' institution, 5 patients (63%) experienced metastasis, 6 patients (75%) experienced long-term recurrence, and 5 patients (62.5%) died. In the literature, most patients (60.3%) were males, with a peak incidence between the 4th and 5th decades of life. Nineteen patients (31.1%) were diagnosed with Carney complex. Nerve root tumors accounted for most presentations (n = 39, 61.9%). Moreover, 24 patients (38.1%) had intradural lesions, with 54.2% (n = 13) being intramedullary and 45.8% (n = 11) extramedullary. Most patients underwent gross-total resection (GTR) (n = 41, 66.1%), followed by subtotal resection (STR) (n = 12, 19.4%), STR with radiation therapy (9.7%), and GTR with radiation therapy (4.8%). Sixteen patients (27.6%) experienced metastasis, 23 (39.7%) experienced recurrence, and 13 (22%) died. Kaplan-Meier analyses showed no significant differences among treatment approaches in terms of recurrence-free, metastasis-free, and overall survival (p > 0.05). Similar results were obtained when looking at the differences with respect to intradural versus nerve root location of the tumor (p > 0.05). CONCLUSIONS: Malignant melanotic nerve sheath tumors are rare tumors with a high potential for malignancy. They carry a dismal prognosis, with a pooled local recurrence rate of 42%, distant metastasis rate of 27%, and mortality rate of 26%. The findings from this study suggest a trend favoring the use of GTR alone or STR with radiation therapy over STR alone. Mortality was similar regardless, which highlights the need for the development of effective treatment options to improve survival in patients with melanotic schwannomas.

Predictors of clinical and structural outcomes after surgery for spinal nerve sheath tumor resection: a retrospective analysis.

OBJECTIVE: Resection of spinal nerve sheath tumors (SNSTs) typically necessitates laminectomy, often with facetectomy, for adequate exposure of tumor. While removal of bone affords a greater operative window and extent of resection, it places the patient at greater risk for spinal instability. Although studies have identified risk factors for fusion at the time of tumor resection, there has yet to be a study assessing long-term stability following SNST resection. In this study, the authors sought to identify preoperative and operative risk factors that predispose to long-term spinal instability and investigate clinical variables associated with greater risk for subsequent fusion in the time following initial SNST resection. METHODS: An institutional registry of spinal surgeries was queried at a single institution over a 20-year period. Demographic, clinical, and operative variables were recorded retrospectively and investigated for predictive value of several postoperative sequelae. RESULTS: A total of 122 SNST cases among 112 patients were included. At a mean follow-up time of 27.7 months, patients with a history of neurofibromatosis type 2 (NF2) (p = 0.014) and those who had undergone a laminectomy of ≥ 4 levels at the time of initial SNST resection (p = 0.028) were more likely to present with some degree of structural abnormality or neurological deficit following their initial surgery. The presence of facetectomy, degree of laminectomy, and level of spinal surgery were not found to be predictors of future instability. Ultimately, there was no significant predictor for true spinal instability following index surgery without fusion. A secondary analysis showed that an entirely extradural location (p = 0.044) and facetectomy at index surgery (p = 0.012) were predictive of fusion being performed at the time of tumor resection. Four of the 112 patients required fusion after their index SNST resection, 3 of whom underwent fusion for instability at the level of the index surgery. No variables were identified as predictive for future instrumentation. CONCLUSIONS: Ultimately, the authors conclude that resection of SNSTs does not always necessitate fusion, and good outcomes can be obtained with motion-preserving techniques and minimizing facetectomy when possible. Patients with a history of NF2 and those with SNSTs that required ≥ 4-level laminectomy were more likely to exhibit some degree of structural abnormality and/or neurological deficit localized to the index level defined as either new or worsening spinal instability and/or new or worsening neurological deficit at last follow-up; however, no variable was found to be predictive of true spinal instability. Furthermore, a complete facetectomy at initial SNST resection and entirely extradural tumor location were noted to be associated with fusion at index surgery. Lastly, the authors were unable to identify a clinical predictor for future instrumentation.

Vaginal malignant peripheral nerve sheath tumor treated with complete surgical resection and postoperative radiation therapy.

Malignant peripheral nerve sheath tumors (MPNSTs) are neoplasms originating from or differentiating into nerve sheaths of peripheral nerves. Vaginal origin is rare, with only six vaginal primary cases reported to date. A 55-year-old woman presented to our hospital with a 7 cm vulvar mass. Tumor biopsy results were suspicious of sarcoma, and pelvic magnetic resonance imaging and hysterofiberscopy showed that the tumor originated from the lower vagina. The mass was transvaginally excised, and histological examination confirmed the diagnosis of a vaginal MPNST with negative surgical margins. The patient underwent radiotherapy because the risk of recurrence was high, owing to the large tumor size and high mitotic index. The patient remained recurrence-free for 1 year after the primary treatment. This is the first case of a high-risk vaginal MPNST that avoided early disease recurrence with additional radiotherapy after complete tumor resection.

When biopsy goes wrong: a case series of misdiagnoses and complications from biopsies of masses of unknown origin potentially originating from a peripheral nerve.

OBJECTIVE: Biopsies of peripheral nerve tumors (PNTs) are often used to plan an efficient treatment strategy. However, performing a biopsy is controversial when the mass is likely to be a benign PNT (BPNT). The aim of this study was to evaluate the side effects of biopsies in patients with potential PNTs. METHODS: A retrospective and cross-sectional study was conducted on 24 patients who underwent biopsy of a mass of unknown origin potentially originating from a peripheral nerve (MUOPON), performed in nonspecialty services, and who were later referred to the authors' service for resection of their lesion between January 2005 and December 2022. The patients were evaluated for pain score, presence of a motor or sensory deficit, biopsy diagnosis, and definitive histopathological postsurgical diagnosis. RESULTS: The location of the tumor was supraclavicular in 7 (29.2%) patients, in the axillary region in 3 (12.5%), in the upper limb in 7 (29.2%), and in the lower limb in 7 (29.2%). Twenty-one (87.5%) patients were evaluated by MRI before biopsy, and 3 (12.5%) underwent ultrasound. One patient did not have an examination before the procedure. Based on the biopsy findings, 12 (50%) analyses had an inconclusive histopathological result. The preexisting pain worsened, as measured 1 week after biopsy, in all patients and had remained unchanged at the first evaluation by the authors (median 3 months, range 2-4 months). In 1 case, the open biopsy had to be interrupted because the patient experienced excruciating pain. Four (16.7%) patients developed motor deficits. Subsequent surgery was hampered by scar formation and intratumoral hemorrhage in 5 (20.8%) patients. The initial diagnosis obtained by biopsy differed from the final histopathological diagnosis in all patients, of whom 21 (87.5%) had BPNTs, 2 (8.3%) malignant peripheral nerve sheath tumors, and 1 (4.2%) an ancient schwannoma. CONCLUSIONS: Biopsies of PNTs are controversial and may result in misdiagnosis, neuropathic pain, or neurological deficit due to axonal damage, and they may also hinder microsurgical resection when if performed when not indicated. Indications for biopsy of an MUOPON must be carefully considered, especially if BPNT is a possible diagnosis.

Epithelioid malignant peripheral nerve sheath tumour of the ulnar nerve around the elbow: a diagnostic and therapeutic challenge.

Epithelioid malignant peripheral nerve sheath tumour (EMPNST) is a rare histological subtype of malignant peripheral nerve sheath tumour (MPNST), accounting for 5% to 17% of MPNSTs. The clinical and MRI findings of EMPNST mimic those of nerve abscesses, similar to the presentation in Hansen's disease. We present one such case with this kind of diagnostic dilemma. Intraoperative findings suggest a tumour changed the course of management subsequently. The development of neurological deficits postoperatively after tumour resection was a reconstructive challenge. To provide motor power and sensation through a procedure that provides a complete functional outcome for a young patient, distal nerve transfers were chosen. This provided an improvement in the quality of life and hastened the neurological recovery of the involved limb. Level of evidence: V.

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

RATIONALE: Neurofibromatosis type 1 (NF1) is an autosomal dominant neurocutaneous syndrome that causes multiple central and peripheral nerve sheath tumors. People with NF1 have a 10% chance of developing malignant peripheral nerve sheath tumors (MPNSTs). Here we report a unique instance of a malignant schwannoma that has remained free of metastasis since its initial removal a decade ago. The malign schwannoma has been infrequently documented in the literature, and remarkably, no instances of such an extensive postoperative time without metastases have ever been described. PATIENT CONCERNS: A 46-year-old male patient with NF had multiple neurofibromas in different parts of his body, underwent surgery about 10 years ago (2013), and was diagnosed histopathologically as MPNST. DIAGNOSES: He was admitted to our institution with a recurrent mass in the posterior third of the proximal thigh and severe pain radiating to the left lower extremity, which presented as sciatic pain (2021). A magnetic resonance imaging and fluorodeoxyglucose-positron emission tomography examination revealed that the tumor was likely malignant. INTERVENTIONS: Surgical excision was performed. OUTCOME: A 10-year follow-up revealed no metastases or neurologic impairment. LESSONS: When articles about benign schwannomas are placed in a separate category, little is written about NF-1-related malignant schwannomas of the sciatic nerve. MPNSTs are high-grade, aggressive sarcomas with a high risk of local recurrence (40%-65%) and metastasis to other body parts. Therefore, among the various benign peripheral nerve sheath tumors in NF-1 patients, the diagnosis of MPNST is crucial.Orthopedic surgeons should be aware that neurofibromas in NF-1 have a significant risk of developing MPNSTs. This study reports the successful treatment of a giant malignant sciatic nerve schwannoma with a long follow-up period without metastasis.

Surgical management of craniospinal axis malignant peripheral nerve sheath tumors: a single-institution experience and literature review.

BACKGROUND: Malignant peripheral nerve sheath tumor (MPNST) is an exceedingly rare and aggressive tumor, with limited literature on its management. Herein, we present our series of surgically managed craniospinal MPNSTs, analyze their outcomes, and review the literature. METHODS: We retrospectively reviewed surgically managed primary craniospinal MPNSTs treated at our institution between January 2005 and May 2023. Patient demographics, tumor features, and treatment outcomes were assessed. Neurological function was quantified using the Frankel grade and Karnofsky performance scores. Descriptive statistics, rank-sum tests, and Kaplan-Meier survival analyses were performed. RESULTS: Eight patients satisfied the inclusion criteria (4 male, 4 female). The median age at presentation was 38 years (range 15-67). Most tumors were localized to the spine (75%), and 3 patients had neurofibromatosis type 1. The most common presenting symptoms were paresthesia (50%) and visual changes (13%). The median tumor size was 3 cm, and most tumors were oval-shaped (50%) with well-defined borders (75%). Six tumors were high grade (75%), and gross total resection was achieved in 5 patients, with subtotal resection in the remaining 3 patients. Postoperative radiotherapy and chemotherapy were performed in 6 (75%) and 4 (50%) cases, respectively. Local recurrence occurred in 5 (63%) cases, and distant metastases occurred in 2 (25%). The median overall survival was 26.7 months. Five (63%) patients died due to recurrence. CONCLUSIONS: Primary craniospinal MPNSTs are rare and have an aggressive clinical course. Early diagnosis and treatment are essential for managing these tumors. In this single-center study with a small cohort, maximal resection, low-grade pathology, young age (< 30), and adjuvant radiotherapy were associated with improved survival.