Diagnostic Pathology of Tumors of Peripheral Nerve

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". 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. This case report aims to raise awareness of the problem of spinal cord MMNST and contribute to greater knowledge of this rare tumor.

Investigations on ultrasonography in the diagnosis of nodular localized cutaneous neurofibroma

OBJECTIVE

To describe the ultrasound characteristics of nodular localized cutaneous neurofibroma (NLCN).

MATERIALS AND METHODS

Clinical features and ultrasound characteristics of 43 lesions of 40 patients pathologically proven as NLCNs at Peking University Shenzhen Hospital from October 2014 to May 2022 were analyzed retrospectively. The location, length-to-thickness (L/T) ratio, thickness-to-width (T/W) ratio, shape, margin, capsule, echogenicity, echotexture, posterior features, vascularity, and "rat tail sign" were evaluated.

RESULTS

All ultrasound findings showed almost perfect agreement. More than a half of NLCNs (n = 24, 55.8%, p < 0.001) were located in the subcutaneous fat layer wholly with well-demarcation from dermis and deep fascia. Most of the NLCNs were fusiform shape (n = 27, 62.8%, p < 0.001) in the long axis and oval shape (n = 35, 81.4%, p < 0.001) in the short axis. The other ultrasound findings of NLCNs included well-defined (n = 42, 97.7%, p < 0.001), encapsulated (n = 39, 90.7%, p < 0.001), predominately hypoechoic (n = 34, 79.1%, p < 0.001), homogeneous (n = 39, 90.7%, p < 0.001), posterior enhancement (n = 29, 67.4%, p = 0.033), and avascularity (n = 37, 86.0%, p < 0.001). Only a quarter (n = 11, 25.6%, p = 0.002) of lesions were recognized with the "rat tail sign."

CONCLUSION

NLCNs present as fusiform shape in long axis and round shape in short axis. The common ultrasound findings of NLCNs are well-defined, encapsulated, predominately hypoechoic, homogeneous lesion with posterior enhancement, and poor blood supply. The "rat tail sign" has low sensitivity in NLCNs.

Biological Implications and Functional Significance of Transglutaminase Type 2 in Nervous System Tumors

Transglutaminase type 2 (TG2) is the most ubiquitously expressed member of the transglutaminase family. TG2 catalyzes the transamidation reaction leading to several protein post-translational modifications and it is also implicated in signal transduction thanks to its GTP binding/hydrolyzing activity. In the nervous system, TG2 regulates multiple physiological processes, such as development, neuronal cell death and differentiation, and synaptic plasticity. Given its different enzymatic activities, aberrant expression or activity of TG2 can contribute to tumorigenesis, including in peripheral and central nervous system tumors. Indeed, TG2 dysregulation has been reported in meningiomas, medulloblastomas, neuroblastomas, glioblastomas, and other adult-type diffuse gliomas. The aim of this review is to provide an overview of the biological and functional relevance of TG2 in the pathogenesis of nervous system tumors, highlighting its involvement in survival, tumor inflammation, differentiation, and in the resistance to standard therapies.

Schwann cells in the normal and pathological lung microenvironment

The lungs are a key organ in the respiratory system. They are regulated by a complex network of nerves that control their development, structure, function, and response to various pathological stimuli. Accumulating evidence suggests the involvement of a neural mechanism in different pathophysiological conditions in the lungs and the development and progression of common respiratory diseases. Lung diseases are the chief source of death globally. For instance, lung cancer is the second most commonly diagnosed malignancy, after prostate cancer in men and breast cancer in women, and is the most lethal cancer worldwide. However, although airway nerves are accepted as a mechanistically and therapeutically important feature that demands appropriate emphasizing in the context of many respiratory diseases, significantly less is known about the role of the neuroglial cells in lung physiology and pathophysiology, including lung cancer. New data have uncovered some cellular and molecular mechanisms of how Schwann cells, as fundamental components of the peripheral nervous system, may regulate lung cancer cells' survival, spreading, and invasiveness in vitro and in vivo. Schwann cells control the formation and maintenance of the lung cancer microenvironment and support metastasis formation. It was also reported that the number of lung cancer-associated Schwann cells correlates with patients' survival. Different factors secreted by Schwann cells, including microRNA, are known to sharpen the lung cancer environment by regulating the tumor-neuro-immune axis. Further clinical and experimental studies are required to elucidate the detailed role of Schwann cells in creating and maintaining pulmonary tumor-neuro-immune axis, which will advance our understanding of the pathogenesis of lung cancer and may inform therapeutic hypotheses aiming neoplasms and metastases in the lung.

MRI features of benign peripheral nerve sheath tumors: how do sporadic and syndromic tumors differ?

OBJECTIVES

To compare MRI features of sporadic and neurofibromatosis syndrome-related localized schwannomas and neurofibromas.

METHODS

In this retrospective study, our pathology database was searched for "neurofibroma" or "schwannoma" from 2014 to 2019. Exclusion criteria were lack of available MRI and intradural or plexiform tumors. Qualitative and quantitative anatomic (location, size, relationship to nerve, signal, muscle denervation) and functional (arterial enhancement, apparent diffusion-weighted coefficient) MRI features of sporadic and syndrome-related tumors were compared. Statistical significance was assumed for p < 0.05.

RESULTS

A total of 80 patients with 64 schwannomas (sporadic: 42 (65.6%) v. syndrome-related: 22 (34.4%)) and 19 neurofibromas (sporadic: 7 (36.8%) v. syndrome-related: 12 (41.7%)) were included. Only signal heterogeneity (T2W p=0.001, post-contrast p=0.03) and a diffused-weighted imaging target sign (p=0.04) were more frequent with schwannomas than neurofibromas. Sporadic schwannomas were similar in size to syndrome-related schwannomas (2.9±1.2cm vs. 3.7±3.2 cm, p = 0.6), but with greater heterogeneity (T2W p = 0.02, post-contrast p = 0.01). Sporadic neurofibromas were larger (4.6±1.5cm vs. 3.4±2.4 cm, p = 0.03) than syndrome-related neurofibromas, also with greater heterogeneity (T2W p=0.03, post-contrast p=0.04). Additional tumors along an affected nerve were only observed with syndrome-related tumors). There was no difference in apparent diffusion coefficient values or presence of early perfusion between sporadic and syndrome-related tumors (p > 0.05).

CONCLUSIONS

Although syndrome-related and sporadic schwannomas and neurofibromas overlap in their anatomic, diffusion and perfusion features, signal heterogeneity and presence of multiple lesions along a nerve are differentiating characteristics of syndrome-related tumors.

Association of plexiform and diffuse neurofibromas with malignant peripheral nerve sheath tumor in NF I patients: a whole-body MRI assessment

OBJECTIVE

The aim of this study is to evaluate neurofibromatosis type 1 (NF1) patients with whole-body MRI (WBMRI) to investigate the frequency of plexiform neurofibromas (pNFs), diffuse neurofibromas (dNFs), and malignant peripheral nerve sheath tumors (MPNSTs).

MATERIALS AND METHODS

In this retrospective cross-sectional study, between the years 2015 and 2023, 83 consecutive patients with known NF1 underwent a total of 110 WBMRI screenings for MPNST using a standardized institutional protocol. The lesions are categorized as discrete lesions, pNFs, dNFs, and MPNSTs. Histopathology served as the reference standard for all MPNSTs.

RESULTS

Among the 83 patients analyzed, 53 (64%) were women and 30 were men (36%) of ages 36.94±14.43 years (range, 15-66 years). Of the 83 patients, 33 have a positive family history of NF1 and positive genetic studies. Seven of 83 (8%) have only dNF, 20/83 (24%) have pNF, 28/83 (34%) have both dNF and pNF, and 28/83 (34%) have neither. Of the 83 patients, eight (9.6%) were diagnosed with nine total MPNSTs. Age range for patients with MPNSTs at time of diagnosis was 22-51, with an average age of 33.4 years. Only one MPNST (11%) developed from underlying pNF 4 years after WBMRI along the right bronchial tree. Three of eight (37.5%) patients with MPNST died within 5 years of pathologic diagnosis.

CONCLUSION

This study suggests the absence of a predisposition for development of MPNST from pNFs and dNFs in the setting of NF1. As such, these lesions may not need special surveillance compared to discrete peripheral nerve sheath tumors.

Differential diagnosis of rare adrenal cellular schwannomas: A case report

BACKGROUND

Adrenal cellular schwannomas are exceptionally rare stromal tumors that are often misdiagnosed due to the lack of specific radiological, serological, or clinical features. In this report, we describe the differential diagnosis of a rare adrenal cellular schwannoma.

METHODS

A 69-year-old man with a history of persistent hypertension, chronic kidney disease, hypertensive heart disease, and cardiac insufficiency was hospitalized due to bilateral lower extremity edema lasting for 3 months. Plain computed tomography at that time revealed a space-occupying lesion in the right adrenal gland. As serum levels of catecholamines, cortisol, and adrenocorticotropic hormone were within normal ranges, the edema was attributed to the chronic kidney disease and cardiac insufficiency, and the patient was referred to our hospital for surgical treatment. Contrast-enhanced computed tomography revealed heterogeneous enhancement in the adrenal mass indicating pheochromocytoma. An irregularly shaped 5 cm mass with a complete capsule in the right adrenal gland was laparoscopically resected. The postoperative histopathological diagnosis was adrenal cellular schwannoma.

RESULTS

The postoperative course was unremarkable and the tumor did not recur during 5 years of follow-up.

CONCLUSION

Adrenal cellular schwannoma is a very rare tumor that is extremely difficult to preoperatively diagnose. Histological and immunohistochemical analyses are required for differential diagnosis and confirmation. Cellular schwannomas can transform into malignant peripheral nerve sheath tumors, but not often. Consequently, regular postoperative follow-up is required for such patients, especially imaging.

18F-FDG PET/CT revealed sporadic schwannomatosis involving the lumbar spinal canal and both lower limbs: a case report

Schwannomatosis is a rare autosomal dominant hereditary syndrome disease characterized by multiple schwannomas throughout the body, without bilateral vestibular schwannoma or dermal schwannoma. The most common location of schwannomatosis is the head and neck, as well as the limbs, while multiple schwannomas in the lumbosacral canal and lower extremities are relatively rare. In this study, we report a 79-year-old woman diagnosed with schwannomatosis. MRI and contrast-enhanced imaging revealed multiple schwannomas in both lower extremities. An 18F-FDG PET/CT examination revealed that in addition to multiple tumors with increased 18F-FDG uptake in both lower extremities, there was also an increased 18F-FDG uptake in a mass in the lumbosacral canal. These masses were confirmed to be schwannomas by pathology after surgery or biopsy. 18F-FDG PET/CT findings of schwannomas were correlated with MRI and pathological components. Antoni A area rich in tumor cells showed significant enhancement on contrast-enhanced T1WI, and PET/CT showed increased uptake of 18F-FDG in the corresponding area, while Antoni B region rich in mucus showed low enhancement on contrast-enhanced T1WI, accompanied by a mildly increased 18F-FDG uptake.

SOX9 Promotes Collagen VI Secretion by Upregulating PCOLCE in Neurofibroma

Neurofibromatosis type 1 (NF1) is caused by NF1 gene mutations. Patients with NF1 often have complications with tumors, such as neurofibroma. In order to investigate the pathogenesis of human neurofibroma, a systematic comparison of protein expression levels between Schwann cell-like sNF96.2 cells, which originated from malignant peripheral nerve sheath tumors (MPNST), and normal Schwann cells was performed using 4-D label-free proteomic analysis. In addition, the expression levels and localization of dysregulated proteins were confirmed using a Gene Expression Omnibus (GEO) transcriptomic dataset, Western blot analysis, and immunofluorescence labeling. The effects of SRY-box transcription factor 9 (SOX9) in the neurofibroma and surrounding microenvironment were evaluated in vivo using a tumor transplantation model. The present study observed that SOX9 and procollagen C-endopeptidase enhancer (PCOLCE) were significantly altered. NF1 mutation promoted the nuclear translocation and transcriptional activity of SOX9 in neurofibromas. SOX9 increased collagen VI secretions by enhancing the activation of PCOLCE in neurofibroma cells. These findings might provide new perspectives on the pathophysiological significance of SOX9 in neurofibromas and elucidate a novel molecular mechanism underlying neurofibromas.

A Rare Case of Schwannoma of the Right Greater Palatine Nerve in a 17-Year-Old Female Patient

Schwannomas are not uncommon in the maxillofacial region; however, those with intraoral localization and, in particular, the hard palate are among the least frequently described. In the current case report, we present a 17-year-old girl with a histologically verified schwannoma of the hard palate on the right, originating from the right greater palatine nerve. In her case, despite the lysis of the palatine bone from the tumor compression, the disease is asymptomatic, causing only a weak sensation of local discomfort. The lesion was removed surgically under general anesthesia and the resulting defect of the palatal mucosa was compensated by plastic reconstruction with a lingual mucosal flap on a posterior feeding base. The recovery period was uneventful.

Dental Developmental Stages and Decayed, Missing, and Restored Teeth in Neurofibromatosis Type 1-affected Children and Adolescents

Background

Neurofibromatosis type 1 (NF1) is an autosomal dominant inherited tumor predisposition disease with a highly variable phenotype. The influence of the characteristic NF1 tumors (neurofibromas) on dentition has not yet been examined in detail. The aim of the study was to assess the dentition of NF1 children and adolescents, considering the symmetry of tooth development.

Material and Methods

The panoramic radiographs of 59 patients with a confirmed NF1 diagnosis were compared with 59 age-and-sex-matched controls. The stages of tooth development on the sides of the jaw, added to a score, were assessed. In addition, the number of filled or decayed teeth, and the number of retained or missing teeth were assessed.

Results

The tooth development of both study groups is symmetrical for almost all parameters and in the same developmental stage according to the sum score of the tooth development stages. Discrete developmental delays of teeth, in particular in the oral area of facial plexiform neurofibroma (PNF) are noticeable. NF1 patients' teeth showed less decay and more restorations than that of the control group. The facial PNF (FPNF) does not impair emergence of deciduous teeth.

Conclusions

Development of dentition of NF1 patients does not differ from the general population. However, FPNF with oral tumor components often prevent mesial movement of permanent molars and premolars, so these teeth do not develop contact (spacing), hardly emerge or may stay retained in bone. Oral PNF may have a low-retarding effect on some tooth root development (e.g., wisdom teeth). This effect is negligible when comparing the affected and unaffected sides of the jaw and is probably non-specific. Key words:Neurofibromatosis type 1, plexiform neurofibroma, dentition, mixed dentition, symmetry, oral health, tooth development.

Distinctive mesenchymal-like neurofibroma stem cells shape NF1 clinical phenotypes controlled by BDNF microenvironment

BACKGROUND

Neurofibroma type I (NF1) often presents with multiple clinical phenotypes due to mutations of NF1 gene. The aim of this study was to determine the phenotypic and therapeutic relevance of tumor microenvironment in NF1 patients.

METHODS

Tumor stem cells (TSCs) from NF1 were isolated and cultured using fluorescence activated cell sorting (FACS) and colony formation experiments. Then, flow cytometry was used to detect the surface markers, osteogenic and adipogenic differentiation were performed as well. Its tumorigenesis ability was confirmed by subcutaneous tumorigenesis in nude mice. Immunohistochemical staining was performed on neurofibroma tissues from the head and trunk with different phenotypes. The expression of BDNF in neurofibroma tissues was detected by Elisa and immunohistochemical staining. Western Blotting was used to detect the expression of p38 MAPK pathway in TSCs. The effect of BDNF neutralizing antibody on the tumorigenesis of TSCs was observed.

RESULTS

Herein, we advocate that NF1 contain a new subgroup of mesenchymal-like neurofibroma stem cells (MNSCs). Such colony-forming MNSCs preserved self-renewal, multiple differentiation and tumorigenic capabilities. More interestingly, the MNSCs isolated from neurofibroma tissues of the same patient with different phenotypes presented site-specific capabilities. Moreover, different levels of brain-derived neurotrophic factor (BDNF) in neurofibroma tissues can impact the MNSCs by activating the TrkB/p38 MAPK pathway. Systemic administration of BDNF neutralizing antibodies inhibited MNSCs' characteristics.

CONCLUSIONS

We demonstrated that BDNF can modulate MNSCs and thereby controlling different tumor phenotypes between the head and trunk regions. Application of BDNF neutralizing antibodies may inhibit p38 MAPK pathway, therefore providing a promising strategy for managing NF1.

[Interdisciplinary Treatment Of Tumorous And Tumour-Like Lesions Of Peripheral Nerves]

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".

Intrapulmonary schwannoma presenting as an asymptomatic lung mass: a case report

BACKGROUND

Schwannomas are solitary well-circumscribed encapsulated benign tumors that exhibit Schwann cell differentiation, and arise directly from myelinated peripheral or central nerves. Although they are usually asymptomatic and found incidentally, schwannomas can cause symptoms due to compression of nearby structures which, depending on the location, can make clinical presentations widely variable. Despite their rarity, schwannomas have been documented in a number of locations including the limbs, cerebellopontine angle, posterior mediastinum, and, far more infrequently, the lungs.

CASE PRESENTATION

In this article, we report an incidental finding of an intrapulmonary schwannoma in a 59-year-old Pakistani woman who was grossly asymptomatic upon presentation to the cardiothoracic surgery clinic. An [18F]fluorodeoxyglucose positron emission tomography/computed tomography scan revealed a lobulated soft-tissue lesion measuring 23 mm × 23 mm in the lower lobe of the right lung. A computed tomography-guided core biopsy of the mass was performed, which revealed a benign spindle cell lesion based on histopathological examination and immunohistochemical staining. The mass was surgically resected via a right lower lobectomy, and subsequently confirmed to be an encapsulated neoplastic lesion composed of well-differentiated Schwann cells. There were no short- or long-term complications, morbidities, or recurrences based on 1-year follow-up.

CONCLUSION

This report underscores the predominantly asymptomatic nature of schwannomas and reemphasizes the efficacy of surgical resection as a safe and curative procedure for a tumor of this nature. Albeit very rare, intrapulmonary schwannomas can be considered a differential diagnosis when encountering solitary asymptomatic pulmonary nodules or masses.

Solitary plexiform neurofibroma of the tongue: report of a case with no evidence of neurofibromatosis type 1

Neurofibromas are frequently present in the skin, but are uncommon in the oral and maxillofacial region. There are three histological variants of neurofibroma: localized, diffuse, and plexiform. The plexiform histological variant of neurofibroma is the least common and is a rare occurrence in the oral cavity. Furthermore, plexiform neurofibroma is usually pathognomonic of neurofibromatosis type 1. A case of solitary plexiform neurofibroma of the tongue with no evidence of neurofibromatosis in a 50-year-old female Chinese patient is reported here. The lesion presented as a single, large, well-circumscribed rounded mass in the left hemi-tongue. The tumour was completely excised. No recurrence was observed at the 6-month follow-up.

A chance to cut is a chance to cure: complete resection of an atypical neurofibroma prevents further progression to malignancy

Plexiform neurofibromas are the hallmark of neurofibromatosis type 1 (NF1) and significantly contribute to the overall burden of disease. While surgical excision has long been the only available therapy, the MEK inhibitor (MEKi) selumetinib has been approved as a non-surgical treatment option for these tumors in 2020 (USA) and 2021 (Europe), respectively. However, selumetinib will result in tumor shrinkage only after several months of therapy and might not prevent malignant transformation of a plexiform neurofibroma that occurs with a frequency of 10-15%. Here, we demonstrate that surgical excision might be the therapy of choice in some plexiform neurofibromas despite the availability of MEKi therapy.

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.

Neurofibromatosis- and schwannomatosis-associated tumors: Approaches to genetic testing and counseling considerations

Neurofibromatosis (NF) and schwannomatosis (SWN) are genetic conditions characterized by the risk of developing nervous system tumors. Recently revised diagnostic criteria include the addition of genetic testing to confirm a pathogenic variant, as well as to detect the presence of mosaicism. Therefore, the use and interpretation of both germline and tumor-based testing have increasing importance in the diagnostic approach, treatment decisions, and risk stratification of these conditions. This focused review discusses approaches to genetic testing of NF- and SWN-related tumor types, which are somewhat rare and perhaps lesser known to non-specialized clinicians. These include gastrointestinal stromal tumors, breast cancer, plexiform neurofibromas with or without transformation to malignant peripheral nerve sheath tumors, gliomas, and schwannomas, and emphasizes the need for inclusion of genetic providers in patient care and appropriate pre- and post-test education, genetic counseling, and focused evaluation by a medical geneticist or other healthcare provider familiar with clinical manifestations of these disorders.

Unusual Clinical Presentation of a Benign Peripheral Nerve Sheath Tumor of the Radial Nerve

Diagnosis of simple benign peripheral nerve tumors (PNT) is usually based on imaging studies and in most cases, surgical excision leads to no significant functional deficit. The clinical presentation is often asymptomatic with incidental imaging findings. We present an unusual clinical presentation of a benign peripheral nerve sheath tumor of the radial nerve.

Diagnosis and Management of Intrascrotal Nerve Tumors: A Systematic Review of the Literature

Scrotal tumors of nerve origin are extremely rare and occur mostly in the extratesticular tissues of scrotum, such as the spermatic cord and epididymis. A systematic search of the literature in PubMed, Medline, and Google Scholar databases concerning intrascrotal nerve tumors was performed by 2 independent investigators. The systematic search retrieved 45 male adults, with a mean age of included patients at 43.9 ± 18.8 years. The majority of nerve tumors were extra-testicular (86.7%), and only 13.3% originated from the testis. Out of that, 51.1% of neoplasms were histologically proved as schwannomas, 44.4% as neurofibromatosis, and 4.4% as malignant peripheral nerve sheath tumors. The majority of patients presented with atypical symptoms such as scrotal swelling (51.1%), while only 4.4% of patients were asymptomatic. Ultrasonography is the diagnostic modality of choice (97.2%) for the detection of primary lesion, while magnetic resonance imaging and computed tomography comprise supplementary diagnostic tools. Surgical excision of the mass was the preferred type of surgery performed (75.6%), whereas orchiectomy was performed only in 22.2% of patients. Intrascrotal tumors of nerve origin are extremely rare neoplasms that present mainly in middle-aged males. Increased clinical suspicion is required for accurate diagnosis of this rare entity.

A rare histopathological variant of Schwannoma with rosette-like arrangements and epithelioid cells: a case report from a histopathologist's perspective

Schwannomas exhibit histopathological variation that leads to diagnostic dilemmas, although less frequent in the oral cavity. We describe a case with unique histopathology and no relevant clinical history that adds to the breadth of literature on the diversity presented by Schwannoma. A 60-year-old female patient presented with a small dome-shaped, asymptomatic swelling on the alveolar ridge 6 years in duration. Histopathologically, it showed rich cellular pathology with a unique arrangement of tumor cells forming irregular rosettes. Each rosette presented with a central core of fibrincollagenous material and the tumor cells were arranged on the periphery, exhibiting epithelioid change with evidence of mild cellular and nuclear pleomorphism. On immunohistochemical evaluation, the cells were strongly and diffusely positive for S-100 and negative for Ki-67. A diagnosis of benign Schwannoma with a rosette-like arrangement with epithelioid change was made. The case report emphasizes the risk of misdiagnosis and the importance of awareness regarding rare histopathological variants of Schwannoma.

Submandibular nodal schwannoma: where did it come from?

SummarySchwannoma, a type of benign neurological tumour arising from Schwann cells, is commonly seen in the head and neck region. However, the incidence of cervical lymph node schwannoma is extremely rare, with only two cases reported in the literature. Schwannomatosis is a disease characterised by a constellation of multiple schwannomas seen in a patient, guided by at least one confirmational histological diagnosis. This is a case of a painless progressively enlarging submandibular swelling which is confirmed as a schwannoma based on histology. The patient is also diagnosed with schwannomatosis as the patient has multiple neurological tumours. Nodal schwannoma has a good prognosis and no documentation of recurrence in the literature. It may arise from sympathetic nerves located within the lymph node.

Malignant Melanotic Nerve Sheath Tumors: A Review of Clinicopathologic and Molecular Characteristics

Malignant melanotic nerve sheath tumor (MMNST) which was formerly known as melanocytic schwannoma, is an uncommon aggressive type of nerve sheath tumor. It originates from nerve roots with clonal Schwann cell proliferation and melanin pigment production. MMNST which was once thought to be a benign tumor is now considered a malignant disease based on the latest 2020 World Health Organization classification of soft tissue tumors. Interestingly, despite the histologic features appearing benign with a low proliferation index, the clinical course of this tumor is malignant, which was demonstrated in case series with high rate of recurrences and metastasis. This tumor can occur sporadically or in patients with an underlying familial predisposition syndrome called, Carney's complex. Affected patients will often harbor a germline mutation in the PRKAR1A gene. MMNST can be histologically difficult to distinguish from malignant melanoma, other melanocytic tumors, and Schwannoma. Having a better understanding of its clinic pathologic characteristics and associated conditions is essential in properly diagnosing and managing affected individuals. This includes the possible need for genetic testing to detect germline mutations, genetic counseling, and surveillance according to published recommendations. In this article, we summarize the clinic pathologic and molecular features of MMNST and discuss what is known about its molecular biology and its associations with predisposing conditions. The review was conducted through an extensive PubMed search using keywords then relevant publications were selected.

Hippo Pathway in Schwann Cells and Regeneration of Peripheral Nervous System

Hippo pathway is an evolutionarily conserved signaling pathway comprising a series of MST/LATS kinase complexes. Its key transcriptional coactivators YAP and TAZ regulate transcription factors such as TEAD family to direct gene expression. The regulation of Hippo pathway, especially the nuclear level change of YAP and TAZ, significantly influences the cell fate switching from proliferation to differentiation, regeneration, and postinjury repair. This review outlines the main findings of Hippo pathway in peripheral nerve development, regeneration, and tumorigenesis, especially the studies in Schwann cells. We also summarize other roles of Hippo pathway in damage repair of the peripheral nerve system and discuss the potential future research which probably contributes to novel therapeutic strategies.

Mesenchymal tumours with melanocytic expression: a potential pitfall in the differential diagnosis of malignant melanoma

Mesenchymal tumours with melanocytic expression can pose a diagnostic challenge because they frequently demonstrate both morphological and immunohistochemical overlap with other cutaneous melanocytic neoplasms. Therefore, they present potential pathological pitfalls that may lead to a misdiagnosis of malignant melanoma. Mesenchymal neoplasms that closely mimic melanoma include malignant melanotic nerve sheath tumour (melanotic schwannoma), epithelioid schwannoma, malignant peripheral nerve sheath, cutaneous syncytial myoepithelioma, clear cell sarcoma of soft tissue, and perivascular epithelioid cell tumour. Awareness of these melanoma mimics is necessary for establishing the correct diagnosis so that the appropriate clinical management can be rendered to the patient. This in-depth review highlights key diagnostic features and molecular genetics and also discusses the differential diagnosis and treatment of mesenchymal tumours that exhibit melanocytic expression.

Behavioral Improvements following Lesion Resection for Pediatric Epilepsy: Pediatric Psychosurgery?

INTRODUCTION

Resection of brain lesions associated with refractory epilepsy to achieve seizure control is well accepted. However, concurrent behavioral effects of these lesions such as changes in mood, personality, and cognition and the effects of surgery on behavior have not been well characterized. We describe 5 such children with epileptogenic lesions and significant behavioral abnormalities which improved after surgery.

CASE DESCRIPTIONS

Five children (ages 3-14 years) with major behavioral abnormalities and lesional epilepsy were identified and treated at our center. Behavioral problems included academic impairment, impulsivity, self-injurious behavior, and decreased social interaction with diagnoses of ADHD, oppositional defiant disorder, and autism. Pre-operative neuropsychiatric testing was performed in 4/5 patients and revealed low-average cognitive and intellectual abilities for their age, attentional difficulties, and poor memory. Lesions were located in the temporal (2 gangliogliomas, 1 JPA, 1 cavernoma) and parietal (1 DNET) lobes. Gross total resection was achieved in all cases. At mean 1-year follow-up, seizure freedom (Engel 1a in 3 patients, Engel 1c in 2 patients) and significant behavioral improvements (academic performance, attention, socialization, and aggression) were achieved in all. Two patients manifested violence pre-operatively; one had extreme behavior with violence toward teachers and peers despite low seizure burden. Since surgery, his behavior has normalized.

CONCLUSION

We identified 5 patients with severe behavioral disorders in the setting of lesional epilepsy, all of whom demonstrated improvement after surgery. The degree of behavioral abnormality was disproportionate to epilepsy severity, suggesting a more complicated mechanism by which lesional epilepsy impacts behavior. We propose a novel paradigm in which lesionectomy may offer behavioral benefit even when seizures are not refractory. Thus, behavioral improvement may be an important novel goal for neurosurgical resection in children with epileptic brain lesions.

Synovial sarcoma of the tibial nerve - case report of a rare tumor in a rare location requiring early diagnosis

BACKGROUND

We present the case of a patient with a rare synovial sarcoma (SS) of the tibial nerve. So far, only 4 cases of patients with SS originating from the tibial nerve have been described in the literature, and our patient is only the second patient whose limb was saved during treatment. Synovial sarcomas are malignant mesenchymal tumors, i.e., tumors arising from connective tissue. Synovial sarcomas account for 5-10% of all soft tissue sarcomas. However, the name synovial sarcoma is misleading, because the tumor does not originate from synovial cells, but rather from primitive mesenchymal cells. The name most likely originated from the localization around the large joints on the limbs, more often on the lower ones, in the area of the knee joints. We point out the aspects of correct and quick diagnosis and subsequent treatment, which has very important effect on the patient's prognosis. Primary less radical excision without prior biopsy verification leads to a higher risk of local recurrence, even if a proper reexcision was performed immediately after biopsy verification of the sarcoma.

CASE PRESENTATION

A woman born in 1949 began to suffer at the end of 2020 with escalating pain under the left inner ankle with a projection to the sole and fingers. Her personal, family work and social history were insignificant. After the initial neurological examination, the patient was sent for an ultrasound examination of the ankle, which showed a lobular mass measuring 50 × 22 × 16 mm and according magnetic resonance imaging, the finding appeared to be a suspicious neurinoma of the tibial nerve. The tumor was surgically excised, without prior biopsy verification: a 50 × 20 mm tumor was dissected in the distal part of the tarsal canal, which grew through the structure of the tibial nerve and in some places into the surrounding area and appeared intraoperatively as a neurofibroma. But histologically the tumor was classified as monophasic synovial sarcoma. The patient was indicated for a wide reexcision of the skin with the subcutaneous tissue of size 91 × 20 × 15 mm. Now the patient is being treated with external radiotherapy to the tumor bed and she is able to walk.

CONCLUSION

This report draws attention to a rare type of malignant nerve tumor, which both clinically and radiologically can mimic benign peripheral nerve sheath tumors. Synovial sarcoma should be considered in very painful resistances, typically located around the joints of the lower limbs, the growth of which can be slow. Because the size of the tumor is a negative prognostic factor, it is necessary to make a timely diagnosis using MR imaging and a biopsy with histological examination and to start treatment quickly. Surgical treatment should take place only after a biopsy with histological examination of the tumor so that it is sufficiently radical and does not have to undergo an additional reoperation, as happened in the case of our patient.

Deep genomic analysis of malignant peripheral nerve sheath tumor cell lines challenges current malignant peripheral nerve sheath tumor diagnosis

Malignant peripheral nerve sheath tumors (MPNSTs) are soft-tissue sarcomas of the peripheral nervous system that develop either sporadically or in the context of neurofibromatosis type 1 (NF1). MPNST diagnosis can be challenging and treatment outcomes are poor. We present here a resource consisting of the genomic characterization of 9 widely used human MPNST cell lines for their use in translational research. NF1-related cell lines recapitulated primary MPNST copy number profiles, exhibited NF1, CDKN2A, and SUZ12/EED tumor suppressor gene (TSG) inactivation, and presented no gain-of-function mutations. In contrast, sporadic cell lines collectively displayed different TSG inactivation patterns and presented kinase-activating mutations, fusion genes, altered mutational frequencies and COSMIC signatures, and different methylome-based classifications. Cell lines re-classified as melanomas and other sarcomas exhibited a different drug-treatment response. Deep genomic analysis, methylome-based classification, and cell-identity marker expression, challenged the identity of common MPNST cell lines, opening an opportunity to revise MPNST differential diagnosis.

Case report: A rare case of massive peripheral nerve melanotic schwannoma and review of the literature

Melanotic schwannoma is a rare tumor with indeterminate biologic behavior and varying treatment recommendations. Just about 200 cases have been reported worldwide, in which occurred in peripheral nerves has even less reported. Due to the lack of cognition of melanotic schwannoma, it is easy to be misdiagnosed and mistreatment in primary hospitals. Herein, we presented a case of massive melanotic schwannoma growing in the brachial plexus of an elderly male patient. First, the patient underwent a left forearm tumor resection in the local primary hospital because a painless lump was found there in 2017, of which details remain unclear. After this operation, the patient developed the symptoms of left median nerve injury. Thus, he came to our hospital and underwent a second operation. During this operation, we found that a part of the median nerve was absent at the left forearm, and the remanent median nerve, from the broken end to the elbow, was totally turned black, which was accompanied by petroleum-like exudate. Losing the opportunity for nerve repair, the black nerve was removed extensively and thoroughly. Postoperative pathological diagnosis revealed that the tumor was melanotic schwannoma. Then 4 years later, the tumor recurrence again, which led to the paralysis of the whole left arm and severe nerve pain, and the pulmonary metastasis of the tumor was detected at the same time. The black nerve was resected again in our hospital, and the nerve pain was partially relieved after the operation. To the best of our knowledge, it is the first time to report a melanotic schwannoma case that happened in the peripheral nerve trunk and then spread to the whole brachial plexus. There were many questions that worthy of discussion could be invited from this case, and we analyzed and discussed them based on the relevant literature. In conclusion, we reported a rare case of melanotic schwannoma that happened in the brachial plexus and illustrated the problems of the diagnosis and treatment of it based on the analysis of the relevant literature, which is helpful for the cognition of this rare nerve tumor.

Immunotherapy for Pediatric Brain and Spine Tumors: Current State and Future Directions

BACKGROUND

Brain tumors are the most common solid tumors and the leading cause of cancer-related deaths in children. Incidence in the USA has been on the rise for the last 2 decades. While therapeutic advances in diagnosis and treatment have improved survival and quality of life in many children, prognosis remains poor and current treatments have significant long-term sequelae.

SUMMARY

There is a substantial need for the development of new therapeutic approaches, and since the introduction of immunotherapy by immune checkpoint inhibitors, there has been an exponential increase in clinical trials to adopt these and other immunotherapy approaches in children with brain tumors. In this review, we summarize the current immunotherapy landscape for various pediatric brain tumor types including choroid plexus tumors, embryonal tumors (medulloblastoma, AT/RT, PNETs), ependymoma, germ cell tumors, gliomas, glioneuronal and neuronal tumors, and mesenchymal tumors. We discuss the latest clinical trials and noteworthy preclinical studies to treat these pediatric brain tumors using checkpoint inhibitors, cellular therapies (CAR-T, NK, T cell), oncolytic virotherapy, radioimmunotherapy, tumor vaccines, immunomodulators, and other targeted therapies.

KEY MESSAGES

The current landscape for immunotherapy in pediatric brain tumors is still emerging, but results in certain tumors have been promising. In the age of targeted therapy, genetic tumor profiling, and many ongoing clinical trials, immunotherapy will likely become an increasingly effective tool in the neuro-oncologist armamentarium.

Clinical characteristics and management experience of schwannoma in extremities: Lessons learned from a 10-year retrospective study

Introduction

Schwannomas are the most common neoplastic lesions of the peripheral nerves when growing on the extremities, they usually have adverse effects on patients due to the exposed and functional nature of the region.

Methods

In the present single-center retrospective study, we included all patients with pathologically confirmed schwannoma located in extremities between 2011 and 2021 totaling 183 patients. Data on gender, age, duration history, clinical presentation, occurrence region, nerve affiliation, imaging data, modus operation, mass volume, immunohistochemistry, postoperative neurological function, and recurrence were collected.

Results

As in previous studies, patients were predominantly middle-aged with a mean age of 49.5, without gender preference and a male-to-female ratio of 1.2:1. Most patients are first seen for this disease, and only five of them are recurrent. The majority presented with an isolated (91.26%), asymptomatic (37.7%) mass, with tenderness (34.97%) being the second frequent complaint. 60% of lesions occurred in the upper extremity, more commonly on the left side (55.26%) than the right. The average duration of onset was 47.50 months. MRI is more sensitive for neurogenic tumors than ultrasound, as it owns 78.93% correct. In immunohistochemistry, the top three markers for positive labeling schwannoma are S-100 (98.95%), Ki67 (98.68%) and β-Catenin. 98.36% of patients underwent complete resection of the lesion, of which 14.44% required partial sacrifice of the nerve fibers. Thanks to the application of intraoperative peripheral nerve microscopic operation, only 6 patients showed symptoms of postoperative nerve injury, and 3 of them received second surgery. Intraoperative microscopic manipulation, preservation of the main nerve, and the need for reconstruction of the affected nerve fibers are some of the points worth noting.

Discussion

In summary, the possibility of schwannoma should not be overlooked in the identification of masses that occur in the upper extremities of the middle-aged population. Preoperative ultrasound and MR are useful for determining the nature of the mass, and S100, Ki67, and β-Catenin are sensitive to it. Surgical resection can achieve satisfying functional results and a low risk of nerve injury.

Benign Neurofibroma/Schwannoma Hybrid Peripheral Nerve Sheath Tumor of the Ulnar Nerve Harboring a Metastatic Papillary Thyroid Carcinoma Deposit: A Case Report of Tumor-to-Tumor Metastasis

A 74-year-old man with a medical history significant for papillary thyroid cancer (PTC) presented with a rapidly enlarging grape-sized mass in his right medial arm with paresthesia in the ulnar nerve distribution. Imaging was suspicious for a peripheral nerve sheath tumor (PNST), but an ultrasound-guided biopsy was equivocal. The mass was excised with final histopathology demonstrating a benign neurofibroma/schwannoma hybrid nerve sheath tumor (N/S HNST) harboring a metastatic PTC deposit, ultimately mimicking the rare glandular schwannoma subtype. Next-generation sequencing (NGS) of the lesion demonstrated somatic variants in BRAF and TERT (common in PTC) and NF2 (common in PNSTs). After excision, the patient's nerve symptoms improved. A postsurgical PET/CT scan also showed progression in the lungs/mediastinum. Due to the metastatic nature of his PTC, he was treated with 14 mg of Lenvima (lenvatinib) daily, and his PET/CT surveillance was performed at more frequent intervals. Tumor-to-tumor metastasis (TTM) is a rare occurrence. To our knowledge, this is the first case reported on PTC metastasizing into a benign (hybrid) PNST, which mimicked glandular schwannoma. Symptomatology, imaging characteristics, NGS, and histopathological characteristics that can decipher between different benign PNST subtypes (schwannoma, neurofibroma, glandular, hybrid, etc.), malignant PNSTs (MPNSTs), and TTM are described.

Characterization and Treatment of Spinal Tumors

The prevalence of spinal tumors is rare in comparison to brain tumors which encompass most central nervous system tumors. Tumors of the spine can be divided into primary and metastatic tumors with the latter being the most common presentation. Primary tumors are subdivided based on their location on the spinal column and in the spinal cord into intramedullary, intradural extramedullary, and primary bone tumors. Back pain is a common presentation in spine cancer patients; however, other radicular pain may be present. Magnetic resonance imaging (MRI) is the imaging modality of choice for intradural extramedullary and intramedullary tumors. Plain radiographs are used in the initial diagnosis of primary bone tumors while Computed tomography (CT) and MRI may often be necessary for further characterization. Complete surgical resection is the treatment of choice for spinal tumors and may be curative for well circumscribed lesions. However, intralesional resection along with adjuvant radiation and chemotherapy can be indicated for patients that would experience increased morbidity from damage to nearby neurological structures caused by resection with wide margins. Even with the current treatment options, the prognosis for aggressive spinal cancer remains poor. Advances in novel treatments including molecular targeting, immunotherapy and stem cell therapy provide the potential for greater control of malignant and metastatic tumors of the spine.

Extra-Gynecological Pelvic Pathology: A Challenge in the Differential Diagnosis of the Female Pelvis

Ultrasound technology with or without color Doppler allows a real-time evaluation of the entire female pelvis including gynecologic and non-gynecological organs, as well as their pathology. As ultrasound is an accurate tool for gynecological diagnosis and is less invasive and less expensive than other techniques, it should be the first imaging modality used in the evaluation of the female pelvis. We present a miscellany of non-gynecological pelvic images observed during the realization of gynecological ultrasound. Transvaginal and transabdominal ultrasound is the first choice among diagnostic techniques for the study of the female pelvis, providing information about gynecological and extra-gynecological organs, allowing for an orientation toward the pathology of a specific organ or system as well as for additional tests to be performed that are necessary for definitive diagnosis.

Rare case of pelvic schwannoma mimicking intra-ligamenter uterine fibroid: A case report

INTRODUCTION AND IMPORTANCE

Schwannomas are benign tumors originating from Schwann cells of nerve fibers. Pelvic schwannomas are extremely rare. Here, we present a case of a 48-year-old woman with a pelvic schwannoma imitating degenerating cystic leiomyoma.

CASE PRESENTATION

A 48-year-old woman presented with brown-yellowish bloody vaginal discharge, fever, abdominal enlargement, and pain. Abdominal ultrasound showed a homogeneous solid mass with a clear border separated from the uterus and left ovary. Computed tomography (CT) scan revealed a multilocular cystic mass with thick septa and solid enhancing component. Histopathological examination showed a mesenchymal tumor composed of cells with fine chromatin. The nuclei were oval or round, and some cells exhibited spindle and cigar-shaped nuclei. Tumor cells had an abundant amount of eosinophilic cytoplasm. Immunohistochemical examination demonstrated positive expression for S100 as specific staining for schwannomas. Mitosis was not found, and hyalinized blood vessels were observed.

CLINICAL DISCUSSION

Compression by the tumor into the surrounding organs, such as the bladder and intestines, could cause difficulty with defecation and urination in patients. The absence of specific signs and symptoms can lead to a misdiagnosis of pelvic schwannoma. Surgery is the treatment of choice. It is difficult to establish a definitive diagnosis before surgery. Laparotomy approach was taken and a histopathological examination was completed to confirm the diagnosis.

CONCLUSION

Unspecified pelvic pain with abdominal mass may suggest a rare tumor such as schwannoma. Transvaginal ultrasonography is incapable of reliably distinguishing between schwannoma and other tumors.

Magnetic Resonance Imaging of Nerve Tumors

Nerve tumors are uncommon soft tissue neoplasms predominantly arising from peripheral nerve sheath and Schwann cells. We review the manifestations of benign peripheral nerve sheath tumors, concentrating on distinguishing imaging features of schwannomas versus neurofibromas with an emphasis on treatment implications. Nevertheless, there is often an overlap between the imaging presentation of these two conditions, making the accurate radiologic diagnosis challenging. Therefore, tissue sampling is often needed for a definitive histologic diagnosis. Treatment planning largely depends on symptoms, location of the lesion, and underlying risk factors. Three major syndromes, neurofibromatosis type 1, type 2, and schwannomatosis, predispose patients to peripheral nerve sheath tumors (PNSTs), with particular concern about the malignant subtype expression. In patients with suspected PNSTs, correlation of imaging findings with clinical findings and genetic tests is helpful for a more accurate diagnosis and disease management. Some imaging features on magnetic resonance imaging and fluorodeoxyglucose-positron emission tomography can be helpful to differentiate malignant from benign subtypes.

Atypically Located Solitary Neurofibroma of the Ulnar Nerve as Inaugural Presentation of a New Genetic Variant of Neurofibromatosis Type 1: A Case Report

We report the case of a 34-year-old woman with hypothenar pain due to a solitary neurofibroma (NF) of the ulnar nerve, with an extrafascicular location, outside Guyon canal, with no clinical evidence of associated neurologic impairment, who was successfully treated with surgical resection. The identification of this isolated tumor led to the diagnosis of a new genetic variant of neurofibromatosis type 1 after genome sequencing. At the 1-year follow-up, the patient remains asymptomatic without recurrence or other peripheral nerve sheath tumors. A solitary NF of a deep-seated nerve is extremely rare, especially in the context of neurofibromatosis type 1. To our knowledge, there are no reports of a NF of the ulnar nerve with an extraneural location. In the presence of a solitary NF related to a deep-seated peripheral nerve, neurofibromatosis type 1 should always be excluded.

Immunotherapeutic treatments for spinal and peripheral nerve tumors: a primer

OBJECTIVE

Spinal and peripheral nerve tumors are a heterogeneous group of neoplasms that can be associated with significant morbidity and mortality despite the current standard of care. Immunotherapy is an emerging therapeutic option to improve the prognoses of these tumors. Therefore, the authors sought to present an updated and unifying review on the use of immunotherapy in treating tumors of the spinal cord and peripheral nerves, including a discussion on mechanism of action, drug delivery, current treatment techniques, and preclinical and clinical studies.

METHODS

Current data in the literature regarding immunotherapy were collated and summarized. Targeted tumors included primary and secondary spinal tumors, as well as peripheral nerve tumors.

RESULTS

Four primary modalities of immunotherapy (CAR T cell, monoclonal antibody, viral, and cytokine) have been reported to target spine and peripheral nerve tumors. Of the primary spinal tumors, spinal cord astrocytomas had the most preclinical evidence supporting immunotherapy success with CAR T-cell therapy targeting the H3K27M mutation, whereas spinal schwannomas and ependymomas had the most evidence reported for monoclonal antibody therapy preclinically. Of the secondary spinal tumors, primary CNS lymphomas demonstrated some clinical response to immunotherapy, whereas multiple myeloma and bone tumor experiences with immunotherapy were largely limited to concept only. Within peripheral nerve tumors, the use of immunotherapy to treat neurofibromas in the setting of syndromes has been suggested in theory, and possible immunotherapeutic targets have been identified in malignant peripheral nerve tumors. To date, there have been 2 clinical trials involving spine tumors and 2 clinical trials involving peripheral nerve tumors that have reported results, all of which are promising but require validation.

CONCLUSIONS

Immunotherapy to treat spinal and peripheral nerve tumors has become an emerging area of research and interest. A large amount of preclinical data supporting the translation of this therapy into practice, aimed at ameliorating the poor prognoses of specific tumors, have been reported. Future clinical studies for translation will focus on the optimal therapy type and administration route to best target these tumors, which often preclude total surgical resection given their proximity to the neural and vascular elements of the spine.