Practical Approach to Histological Diagnosis of Peripheral Nerve Sheath Tumors: An Update

Case Report: Two cases of atypical neurofibroma neoplasm of uncertain biological potential in the nasal cavity and a literature review

Objective

This study aims to investigate the clinical diagnosis, treatment processes, and pathological characteristics of two cases of atypical neurofibroma neoplasm of uncertain biological potential (ANNUBP) located in the nasal cavity.

Materials and Methods

We retrospectively analyzed the medical history, imaging studies, pathological results, and follow-up data of two patients diagnosed with nasal ANNUBP who were admitted to Qingdao University Hospital between June and October 2023. A review of relevant literature was conducted to summarize their clinical characteristics, diagnosis, treatment, and prognosis.

Results

Both patients underwent surgical treatment, with one receiving postoperative radiotherapy. Follow-up evaluations indicated that both patients experienced satisfactory recovery, with no signs of local recurrence or distant metastasis.

Conclusion

ANNUBP is a recently recognized and rare subtype of neurogenic tumor. Surgical intervention is regarded as an effective treatment method. This study adhered to established treatment principles for nasal tumors and achieved satisfactory outcomes through surgical intervention and diligent postoperative follow-up.

Rare multiple schwannomas of the left upper extremity: A case report

Schwannomas are rare benign neoplasms originating from Schwann cells of peripheral nerve sheaths. The current study presents a distinctive case involving multiple schwannomas along the peripheral nerves of the left upper extremity. The patient exhibited multiple gradually enlarging subcutaneous masses distributed along the nerves of the left upper limb, without pain, neurological deficits or a positive Tinel's sign upon physical examination. Preoperative diagnostic imaging, including high-resolution ultrasonography and magnetic resonance imaging, revealed well-circumscribed, homogeneous soft-tissue masses with characteristic features. Despite these findings, imaging modalities demonstrated limited specificity in conclusively differentiating the upper extremity tumors from other soft-tissue neoplasms. Surgical exploration conducted under general anesthesia identified three encapsulated masses with focal capsular discontinuities, adherent to surrounding skeletal muscle and the median nerve. The masses measured 6×5×3, 5×4×3.5 and 5×3.5×3 cm from proximal to distal, respectively. Complete surgical excision was performed with meticulous preservation of adjacent neurovascular structures. Histopathological analysis confirmed the diagnosis of schwannomas. This report also provides an extensive review of the literature addressing the etiology, clinical presentation, diagnostic techniques and treatment strategies for peripheral nerve schwannomas, contributing to a deeper understanding of this rare neurogenic tumor and aiding in its effective clinical management.

Hybrid Benign Peripheral Nerve Sheath Tumors: A Comprehensive Literature Review with Emphasis on Their Clinical, Morphological and Genetic Features

Hybrid Peripheral Nerve Sheath Tumors (HPNSTs) are rare benign neoplasms that exhibit a combination of histological features from multiple types of benign peripheral nerve sheath tumors, including schwannomas, neurofibromas, and perineuriomas. These tumors present a diagnostic challenge due to their morphological and histological variability. In this article, we aim to summarize the key morphological, histological, and molecular characteristics of HPNSTs, providing insights into their diagnostic approaches. We review the different hybrid subtypes, including schwannoma-perineurioma, schwannoma-neurofibroma, and perineurioma-neurofibroma, emphasizing their clinical features, genetic associations, and the role of surgical excision as the gold-standard treatment.

Microcystic/Reticular Schwannoma of the Skin: A Report of a Rare Case and Brief Literature Review

Schwannomas, categorized under benign peripheral nerve sheath tumors, exhibit a range of rare histological variants, including ancient, plexiform, pseudoglandular, epithelioid, and microcystic/reticular (MR). These variants pose a significant diagnostic challenge. In this report, we describe a case of a 34-year-old female who presented with a two-year history of a mass on her upper back. Histopathological examination revealed a well-defined and encapsulated subcutaneous nodule displaying a biphasic architecture. The predominant component consisted of hypocellular spindle cells forming reticular and cystic spaces adjacent to compressed hypercellular areas. Immunohistochemistry displayed diffuse and strong positivity for S-100 and SOX-10 while lacking expression of specific melanocytic markers, anaplastic lymphoma kinase (ALK), and cytokeratins (CKs). Intracapsular spindle cells were positive for epithelial membrane antigen (EMA). Based on these distinctive features, we arrived at the diagnosis of an MR schwannoma, an entity rarely reported in the skin. We will discuss the differential diagnosis of cutaneous neoplasms exhibiting reticular and microcystic patterns.

Ancient schwannoma of the submandibular gland

Schwannomas, benign tumours derived from Schwann cells, exhibit slow growth rates and are commonly found extracranially in the head, neck and extremities. However, intraoral and salivary gland schwannomas are less frequent. Ancient schwannomas, characterised by histological degenerative changes, represent a rare variant.This report pertains to a case study involving a man in his 40s who presented with a slow, progressive and painless mass in the right submandibular region persisting over 3 years.CT revealed a well-defined multiloculated cystic mass in the right submandibular gland, later confirmed as an ancient schwannoma on excision and histological examination. Immediate postoperative complications included right marginal mandibular nerve palsy, fully resolving within 12 months. No recurrent tumours were detected in subsequent physical examinations and imaging.Ancient schwannomas, although rare, can occur in the submandibular gland. Thorough multimodal diagnostic approaches are essential for accurate differentiation from other submandibular masses.

Surgical management of a large neurofibroma in the thenar Region: A case report

INTRODUCTION

Neurofibromas are rare benign tumors of peripheral nerve sheaths, and hand involvement is particularly uncommon. This case report presents a large neurofibroma located in the thenar region, a critical area for thumb opposition and hand dexterity, posing unique surgical challenges.

PRESENTATION OF CASE

A 23-year-old female presented with a 3-year history of a progressively enlarging mass in the thenar region of the right hand, accompanied by nocturnal pain but no neurological deficits. MRI revealed a well-circumscribed, multilobulated tumor measuring 54 × 55 × 33.4 mm. Surgical excision was successfully performed while preserving the median nerve. Postoperative recovery was assessed using the QuickDASH questionnaire, yielding a score of 6, indicative of excellent functional outcomes. Histopathology confirmed a benign neurofibroma.

CLINICAL DISCUSSION

The large size and rare location of this tumor, combined with the absence of neurofibromatosis type 1, make this case noteworthy. Early diagnosis and meticulous surgical planning enabled complete excision while preserving critical structures, resulting in full functional recovery with no recurrence after 18 months.

CONCLUSION

This case underscores the importance of individualized surgical strategies for managing neurofibromas in functionally critical areas. While excellent long-term outcomes were achieved in this instance, further studies are needed to validate these findings and refine management approaches.

NTRK3-EML4-rearranged spindle cell tumor with co-expression of S100 and CD34: an unusual mesenchymal tumor in the spectrum of the bland-looking spindle cell lesions of the oral cavity

A novel category of spindle cell tumors characterized by Neurotrophic Tyrosine Receptor Kinase (NTRK) rearrangements with a dual immunoreactivity for S-100 and CD34 has emerged in the last years as a distinct entity among soft tissue neoplasms. These genetic alterations lead to the continuous activation of NTRK genes, driving tumorigenesis and offering a unique prospect for targeted therapy. We herein present a rare case of NTRK3-rearranged spindle cell tumor with a hitherto unreported gene fusion involving the exon 14 of NTRK3 with the exon 2 of Echinoderm Microtubule-Associated Protein-Like 4, arising in the head and neck region. Tumor occurred in a 45-year-old patient who presented with a painful nodule in the oral mucosa. Due to the possibility of personalizing the treatment strategy for such tumors, pathologists should be aware of this emerging group of spindle cell tumors to promptly recognize them even when they occur in uncommon locations, including the oral cavity.

Atypical presentation of long-standing hand neurofibroma: A case report

INTRODUCTION AND IMPORTANCE

A solitary neurofibroma of the hand is an uncommon condition that typically lacks distinct symptoms, often resulting in misdiagnosis and prolonged morbidity. While it primarily affects younger individuals, it can also present in older adults. This article discusses an extraordinary case of a long-standing neurofibroma in the hand.

CASE PRESENTATION

A 70-year-old right-handed individual, known to have hypertension and a pacemaker, presented with a mass on the palm of his left hand. This mass was associated with tingling and mild pain, particularly after excessive use of the hand. Recently, he had experienced partial limitations in hand movement due to the mass's pressure. Following a thorough clinical assessment, he underwent surgical excision of the mass under local anesthesia. Histopathological findings confirmed the diagnosis of neurofibroma. The follow-up was generally uneventful, apart from some persistent tingling sensations.

CLINICAL DISCUSSION

Solitary neurofibromas affecting small nerves are not frequently encountered in clinical practice and usually appear as a slowly progressive mass that may cause pain and tingling. There are no particular radiological approaches that can definitively diagnose this condition; however, histopathological findings have proven effective in confirming the diagnosis.

CONCLUSION

Long-term hand neurofibroma is an infrequent disorder that typically lacks prominent symptoms, highlighting the critical need for medical assessment. Surgery is the only effective treatment for hand cases, providing both a definitive diagnosis and the possibility of being performed with regional anesthesia.

Epidemiological, Clinical, and Histopathological Features of the Head and Neck Region Schwannomas-Our Experience in the Western Part of Romania with Surgical Insights

INTRODUCTION

Schwannomas are benign solitary, slow-growing, encapsulated, asymptomatic tumors arising from Schwann's sheath of nervous fibers.

OBJECTIVES

The current paper presents all the cases diagnosed with different types of schwannomas in the head and neck region between January 2009 and December 2023 in the Western part of Romania. In this period, ten cases of schwannoma were identified.

MATERIALS AND METHODS

The pathological exams were performed at the Department of Pathology using morphological Hematoxylin-Eosin staining. In addition, immunohistochemical reactions were used in order to confirm the diagnosis.

RESULTS

Demographic and clinical data, imaging features, surgical approach, and morphological and immunohistochemical aspects are presented. The results also display an impressive clinical picture of a gigantic ancient schwannoma.

CONCLUSIONS

This retrospective study describes our experience with head and neck schwannomas, the diagnostic methods available, the surgical decisions, and the histopathological aspects while analyzing the data and reviewing the published specialized literature in the English language.

[Progress in neurosurgical treatment of neurofibromatosis type 1]

Objective

To summarize the latest developments in neurosurgical treatments for neurofibromatosis type 1 (NF1) and explore therapeutic strategies to provide comprehensive treatment guidelines for clinicians.

Methods

The recent domestic and international literature and clinical cases in the field of NF1 were reviewed. The main types of neurological complications associated with NF1 and their treatments were thorough summarized and the future research directions in neurosurgery was analyzed.

Results

NF1 frequently results in complex and diverse lesions in the central and peripheral nervous systems, particularly low-grade gliomas in the brain and spinal canal and paraspinal neurofibromas. Treatment decisions should be made by a multidisciplinary team. Symptomatic plexiform neurofibromas and tumors with malignant imaging evidence require neurosurgical intervention. The goals of surgery include reducing tumor size, alleviating pain, and improving appearance. Postoperative functional rehabilitation exercises, long-term multidisciplinary follow-up, and psychosocial interventions are crucial for improving the quality of life for patients. Advanced imaging guidance systems and artificial intelligence technologies can help increase tumor resection rates and reduce recurrence.

Conclusion

Neurosurgical intervention is the primary treatment for symptomatic plexiform neurofibromas and malignant peripheral nerve sheath tumors when medical treatment is ineffective and the lesions progress rapidly. Preoperative multidisciplinary assessment, intraoperative electrophysiological monitoring, and advanced surgical assistance devices significantly enhance surgical efficacy and safety. Future research should continue to explore new surgical techniques and improve postoperative management strategies to achieve more precise and personalized treatment for NF1 patients.

H3K27me3 Loss in Central Nervous System Tumors: Diagnostic, Prognostic, and Therapeutic Implications

Central nervous system (CNS) tumors represent a formidable clinical challenge due to their molecular complexity and varied prognostic outcomes. This review delves into the pivotal role of the epigenetic marker H3K27me3 in the development and treatment of CNS tumors. H3K27me3, specifically the trimethylation of lysine 27 on the histone H3 protein, plays a crucial role in regulating gene expression and maintaining chromatin architecture (e.g., in X-chromosome inactivation). Notably, a reduction in H3K27me3 levels, frequently tied to mutations in the H3 gene family such as H3F3A and HIST1H3B, is evident in diverse brain tumor variants, including the diffuse midline glioma characterized by the H3K27M mutation and certain pediatric high-grade gliomas. The loss of H3K27me3 has been linked to more aggressive behavior in meningiomas, with the trimethylation loss associated with significantly shorter recurrence-free survival (RFS) among grade 2 meningiomas, albeit not within grade 1 tumors. Pediatric posterior fossa ependymomas characterized by a lowered H3K27me3 and DNA hypomethylation exhibit poor prognosis, underscoring the prognostic significance of these epigenetic alterations in CNS tumors. Comprehending the role of H3K27me3 in CNS tumors is vital for advancing diagnostic tools and therapeutic interventions, with the goal of enhancing patient outcomes and quality of life. This review underscores the importance of ongoing investigations into H3K27me to refine and optimize management strategies for CNS tumors, paving the way for improved personalized medicine practices in oncology.

The intriguing perineurial cells - an updated overview of their origin, structure, functions and implication in pathology

The paper overviews the uniquely intricate and distinct perineurium that envelops nerve fibers in bundles. It consists of perineurial cells (PCs), connective tissue, and blood vessels. The perineurium creates a microenvironment for efficient signal transmission, protects and maintains neuronal structure and function, and facilitates neuronal repair. PCs are a unique type of myofibroblasts essential for maintaining nerve homeostasis. They act as an effective blood-nerve barrier (BNB), protecting against toxins, infections, and mechanical trauma. Despite their crucial function, the origin, ultrastructure, molecular structure, and functional roles of PCs remain a mystery, making them a fascinating area of study.

Hybrid peripheral nerve sheath tumours - A Review

Hybrid peripheral nerve sheath tumours (PNSTs) are mainly benign, which represent combined areas of neurofibroma, schwannoma, and perineurioma in various combinations and pose challenges to the surgeon and the pathologist. They are relatively new in pathology and were first published in the fourth edition of World Health Organization Classification of Tumors of Soft tissue and Bone in 2013. They are mainly dermal or subcutaneous, and the most common variant of hybrid nerve sheath tumour is perineurioma-schwannoma. The combination of neurofibroma/schwannoma usually has an increased frequency with neurofibromatosis (NF) type 1 or 2 and schwannomatosis. In contrast, neurofibroma/perineurioma, mainly associated with NF1, are rare. Diagnosis is established by histopathology and immunohistochemistry. Hence, they embark diagnostic challenge and demand extreme vigilance and caution. However, the molecular pathogenesis, recurrence rates, and risk of malignant transformation of hybrid PNST remain poorly understood. A novel CHD7-VGLL3 fusion gene in a hybrid schwannoma-perineurioma and recurrent ERBB2 mutations in a subset of hybrid neurofibroma/schwannomas were identified. We have tried, via this article, to represent a brief update on hybrid nerve sheath tumours.

Schwannoma at an Unusual Site: Case Report and Surgical Technique Discussion for Nasal Dorsum

Peripheral nerve sheath tumors (PNSTs), while uncommon, can have a significant impact on appearance and quality of life, especially when they form in prominent areas such as the nose dorsum. We discuss a case of a 29-year-old woman who developed a benign PNST on the right side of her nasal ala. This tumor gradually grew, impairing her face appearance. Diagnostic tests, such as computed tomography (CT) and magnetic resonance imaging (MRI), revealed the tumor as a slowly growing, well-defined mass. The tumor was removed via open rhinoplasty under general anesthesia, and pathological investigation verified its benign nature. After surgery, the patient's quality of life improved significantly, and there were no evidence of tumor recurrence after eight months. This case emphasizes the need of including PNST in the differential diagnosis of nasal tumors.

Intravascular schwannoma as an extremely unusual cause of vein obstruction: a case report

The blood vessel lumen is an extremely rare location for a benign peripheral nerve sheath tumor like schwannoma. Less than 10 cases have been previously reported. In this report, we present a case of a 68-year-old woman who had a soft tissue nodule at the posterior calf of her left leg during a physical examination. Pathological examination was performed after complete surgical excision. The patient underwent follow-up for 12 months after surgery without evidence of recurrence or any other complication. This is the first case of intravascular schwannoma reported as a cause of vein obstruction. Microscopically, the tumor was composed of Schwann spindle cells that were immunoreactive for S100 protein and SOX10. This tumor was surrounded by a well-defined vascular smooth muscle wall. Prospective series are required to improve the knowledge on the underlying mechanisms of intravascular schwannoma development.

Schwannoma of the Lower Limb: A Case Report

Schwannoma is a benign tumor of the peripheral nerve sheath and is a unique clinical entity when localized to a lower limb. Growing as a painless nodule, it might be misdiagnosed by many medical professionals as another benign soft tissue skin condition, such as lipoma, myxoma, or ganglion cyst. Definitive diagnosis of peripheral schwannoma is made by biopsy and histopathologic evaluation, followed by surgical excision, which is the definitive treatment of the tumor. Classic symptoms of schwannoma of the lower limb are peripheral neuropathy (tingling, burning sensations) and motor impairment (weakness, paralysis of the affected limb). MRI imaging and biopsy are the most useful diagnostic methods for peripheral schwannoma, followed by surgical excision, which is the treatment of choice. Postoperative complications, if present, are minimal and rare. Because of the slow-growing nature of the tumor and the complexity of the lower limb's nervous and structural network, it is often asymptomatic and is challenging to diagnose at a primary stage. That is why we want to spread awareness and draw the reader's attention to this rare case of a patient with schwannoma on the left lower limb.

Laparoscopic-assisted Resection of a Retroperitoneal Lumbar Nerve Root Neurofibroma: A Case Report

We present a case of a 59-year-old patient with chronic low back pain, caused by a retroperitoneal intraneural tumour. Laparoscopic excision was performed and histology revealed a spinal nerve root neurofibroma. Post-operatively, the patient developed partial motor and sensitive deficits due to tumoral nerve entrapment, with progressive recovery with rehabilitation. This report reviews the literature on this sparsely reported condition, highlighting the utility of laparoscopy in its management.

Chest Wall Synovial Sarcoma: A Unique Encounter at the Breast Base

Synovial sarcomas most commonly arise in the para-articular locations of the extremities, such as the upper limbs, thigh, knee, ankle, and foot. Thoracic synovial sarcomas are a rare entity that can arise in the chest wall, pleura, lung, heart, or mediastinum. We present a case of a 23-year-old female with a complaint of swelling of the left breast. Examination demonstrated an enlarged left breast and a hard-fixed swelling without overlying skin changes or nipple retraction. Ultrasound showed a well-defined, solid-appearing lesion deep in the left breast parenchyma, which was adherent to the underlying left chest wall musculature and seemed to be displacing the breast parenchyma anteriorly. Contrast-enhanced computed tomography (CECT) and magnetic resonance imaging (MRI) confirmed the lesion centered at the left pectoralis major and minor muscles, confirming the chest wall's origin. Histopathology findings favored monophasic synovial sarcoma.

Correlation between imaging and histology in benign solitary retroperitoneal nerve sheath tumors: a pictorial review

BACKGROUND

Benign nerve sheath tumors presenting as solitary retroperitoneal masses (RBNSTs) pose a complex diagnostic challenge for multidisciplinary teams regarding differential diagnosis, staging, and treatment planning. This article reviews the role played by different imaging techniques in assessing RBNSTs and elucidates their typical pathological features with a particular emphasis on the correlation between imaging and histological findings. Furthermore, some examples of retroperitoneal tumors that merit consideration in the process of differential diagnosis based on cross-sectional investigations (CSIs) are reported. The correlation between tissue architecture and appearance on imaging can help increase the accuracy of differential diagnosis with other retroperitoneal neoplasms at CSIs.

CRITICAL RELEVANCE STATEMENT

This educational review critically examines the correlation between imaging and histological features in solitary retroperitoneal benign nerve sheath tumors, offering valuable insights for improving the accuracy of differential diagnosis in clinical radiology.

KEY POINTS

RBNSTs are challenging to diagnose because they lack specific radiological features. Differential diagnosis of RBNSTs from other retroperitoneal neoplasms on imaging is complex. Surgical removal of RBNSTs is recommended for an accurate diagnosis.

Intradural cystic schwannomas of the spine: A case-based systematic review of an unusual tumor

Introduction

Cystic schwannomas have only been reported in a few case reports/series. As a result, they may be misdiagnosed and a standardized management approach remains challenging to establish.

Research question

The aim of this study was to compile all reported cases of cystic schwannomas and analyze the perioperative course based on a systematic review of the literature with an additional two cases from the authors' experience.

Material and methods

We conducted a search of MEDLINE and CENTRAL databases for spinal intradural extramedullary cystic schwannomas, in accordance to the PRISMA statement. All title/abstracts were screened, and a full-text review of the remaining articles was conducted. The results were compiled in tables and summarized using means and standard deviation (SD), median and interquartile range, and percentage and 95% confidence intervals.

Results

We identified 263 articles, of which 35, which reported 54 cases, were included. Including our case-reports (n = 56), patients had a mean age of 47.7 years (SD ± 13.0 years) at presentation, 57% were males, and most lesions were lumbar (43%). The most common symptoms were pain (82%) and muscle weakness (68%) with 84% of patients showing neurological findings. 70% of patients showed a complete relief of symptoms after surgery and 96% reported improvement. Only four complications were reported.

Discussion and conclusion

Schwannomas should be considered in the differential diagnosis of intradural extramedullary cystic lesions. Patients typically present with subacute to chronic pain and/or neurologic changes. Surgical resection is the primary therapeutic modality and usually has a good to excellent outcome.

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.

A Child Plexiform Neurofibroma of the Temple Region: A Case Report

Plexiform neurofibroma is a rare variant of neurofibromatosis type 1. Diagnosis is challenging due to the highly variable clinical presentation. Early diagnosis is essential for appropriate treatment and prevention of complications. This report describes a sporadic solitary plexiform neurofibroma in the temporal region of a seven-year-old girl. The growth of the mass began at birth and grew steadily over five years. Subsequently, the mass began to expand rapidly. The patient underwent complete surgical resection under general anesthesia. Histopathological examination revealed a plexiform neurofibroma. In conclusion, surgical excision is the gold standard for cases with symptomatic, visible, large superficial lesions.

A Misdiagnosed Familiar Brooke-Spiegler Syndrome: Case Report and Review of the Literature

Aim of the report: Brooke-Spiegler syndrome (BSS) is a rare autosomal dominant disease characterized by the growth of cylindromas, spiradenomas, trichoepitheliomas, or their combination. These neoplasms usually begin in the second decade and progressively increase in number and size over the years. Diagnosis necessitates consideration of family history, clinical examination, histological findings, and genetic analysis. The aim of this paper is to explore the clinical overlap between Brooke-Spiegler syndrome (BSS) and neurofibromatosis type 1 (NF1). We aim to highlight the challenges associated with their differential diagnosis and emphasize the lack of standardized diagnostic criteria and treatment approaches. Case presentation: Hereby, we introduce the case of a 28-year-old male referred for suspicion of neurofibromatosis type 1 (NF1) who initially declined the recommended surgical excision for a scalp mass. After four years, he returned with larger masses of the scalp, and underwent excision of multiple masses, revealing cylindromas, spiradenomas, and spiradenocylindromas. Family history reported similar tumors in his father, who was also diagnosed with NF1 for the presence of multiple subcutaneous lesions on the scalp. Clinical overlap led to a genetic consultation, but testing for CYLD mutations yielded no significant variations. Despite this, the strong family history and consistent findings led to a revised diagnosis of Brooke-Spiegler syndrome, correcting the initial misdiagnosis of NF1 syndrome. Conclusions: Thanks to the evolving landscape of BSS research over the past two decades, its molecular underpinnings, clinical presentation, and histopathological features are now clearer. However, a thorough family history assessment is mandatory when BSS is suspected. It is our belief that a multidisciplinary approach and cooperation between specialists are essential when dealing with BSS. By sharing this case, we hope to underscore the importance of considering BSS as a differential diagnosis, especially in cases with atypical presentations or overlapping features with other syndromes like NF1.

Neonatal Paratesticular Scrotal Mass: A Rare Case of Atypical Neurofibromatous Neoplasm with Uncertain Biologic Potential

ABSTRACT

Atypical neurofibromatous neoplasm with uncertain biologic potential presenting as a paratesticular scrotal mass in a neonate with congenital giant melanocytic nevus is rare. Only one such case of neonatal scrotal neurofibroma has been reported earlier. We report an additional case and its management.

Expanding a precision medicine platform for malignant peripheral nerve sheath tumors: New patient-derived orthotopic xenografts, cell lines and tumor entities

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft-tissue sarcomas with a poor survival rate, presenting either sporadically or in the context of neurofibromatosis type 1 (NF1). The histological diagnosis of MPNSTs can be challenging, with different tumors exhibiting great histological and marker expression overlap. This heterogeneity could be partly responsible for the observed disparity in treatment response due to the inherent diversity of the preclinical models used. For several years, our group has been generating a large patient-derived orthotopic xenograft (PDOX) MPNST platform for identifying new precision medicine treatments. Herein, we describe the expansion of this platform using six primary tumors clinically diagnosed as MPNSTs, from which we obtained six additional PDOX mouse models and three cell lines, thus generating three pairs of in vitro-in vivo models. We extensively characterized these tumors and derived preclinical models, including genomic, epigenomic, and histological analyses. Tumors were reclassified after these analyses: three remained as MPNSTs (two being classic MPNSTs), one was a melanoma, another was a neurotrophic tyrosine receptor kinase (NTRK)-rearranged spindle cell neoplasm, and, finally, the last was an unclassifiable tumor bearing neurofibromin-2 (NF2) inactivation, a neuroblastoma RAS viral oncogene homolog (NRAS) oncogenic mutation, and a SWI/SNF-related matrix-associated actin-dependent regulator of chromatin (SMARCA4) heterozygous truncated variant. New cell lines and PDOXs faithfully recapitulated histology, marker expression, and genomic characteristics of the primary tumors. The diversity in tumor identity and their specific associated genomic alterations impacted treatment responses obtained when we used the new cell lines for testing compounds against known altered pathways in MPNSTs. In summary, we present here an extension of our MPNST precision medicine platform, with new PDOXs and cell lines, including tumor entities confounded as MPNSTs in a real clinical scenario. This platform may constitute a useful tool for obtaining correct preclinical information to guide MPNST clinical trials.

Case report and literature review: plexiform schwannoma in the penile and inguinal region in a child

Penile schwannoma is an uncommonly seen peripheral nerve tumor, of which penile plexiform schwannomas (PS) is extremely rare that has only been reported in several adults. We present a case of penile PS with a similar lesion in inguinal region in a 9-year-old child, which appeared as painless masses and rapidly growing within one year. Penile ultrasonography suggested well-defined lesions with limited vascularity. Both masses presented with low-to-intermediated signal intensity and no definite enhancement in computed tomography. The lesions were completely resected with minimal intraoperative bleeding, and a diagnose of benign PS was confirmed based on H&E staining and positive S-100 expression in immunohistochemistry. There was no evidence of tumor recurrence or metastasis after 6 months of follow-up. Only 6 cases of penile schwannoma in children were recorded, of which 5 were malignant, and none was PS. The malignancy rate of penile schwannoma in children may be overestimated due to delayed diagnose of benign ones. A rapidly growing penile mass with a suspected metastatic lesion in inguinal region could be easily misdiagnosed as malignant. This case report and literature review is expected to assist clinicians in getting a comprehensive understanding of children penile schwannomas and choosing the best management strategy when faced with this rare condition.

[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".

Nerve sheath tumor in the forearm of a common marmoset (Callithrix jacchus)

Tumors of the skin and subcutaneous tissues are uncommon in marmosets. In this report, we describe the gross, histopathology, and immunohistochemical findings of a nerve sheath tumor that arose in the left forearm of an adult female marmoset (Callthrix jacchus).

A Rare Case of Hepatic Schwannoma in the Setting of Schwannomatosis

Schwannomas are benign nerve sheath tumors commonly found in the head, neck, vestibular system, and extremities. Primary hepatic schwannomas are exceptionally rare, with 34 cases reported to date according to our review of the literature. This case report describes a 79-year-old man with a medical history of skin and thyroid cancer, who presented with no clinical symptoms and underwent a follow-up MRI due to an initial scan indicating a suspicious hepatic mass resembling an atypical hemangioma. The MRI revealed a 3.6 cm left hepatic mass concerning for an intrahepatic cholangiocarcinoma. Histopathological and immunohistochemical studies of a biopsy of the liver mass confirmed the presence of a benign hepatic schwannoma. Further evaluation revealed multiple spinal schwannomas, leading to the diagnosis of schwannomatosis. The diagnosis of hepatic schwannomas poses challenges through imaging alone. This case underscores the importance of microscopic evaluation in accurately diagnosing hepatic masses. Additionally, the presence of concurrent schwannomas should be considered in patients initially diagnosed with isolated schwannomas.

The Expression of Mucin-4 (MUC4) in Sarcomas Apart From Sclerosing Epithelioid Fibrosarcoma and Low-Grade Fibromyxoid Sarcoma

Background Low-grade fibromyxoid sarcoma (LGFMS) and sclerosing epithelioid fibrosarcoma (SEF) are two rare but aggressive soft tissue sarcomas that can be difficult to distinguish due to histopathological similarities. The present study examines the diagnostic capacities of mucin-4 (MUC4), a transmembrane mucin, in identifying different types of sarcomas and broadens its evaluation to include a wide range of sarcomas. Methods Immunohistochemical (IHC) examination of tissue samples from various sarcomas was performed using a mouse anti-MUC4 monoclonal antibody. IHC was conducted on 4-mm thick formalin-fixed paraffin-embedded tissue sections after pressure cooker antigen retrieval with a mouse anti-MUC4 monoclonal antibody. Results MUC4 was shown to be highly expressed in SEF (n=13) and LGFMS (n=10), while focal positivity in synovial sarcoma (n=1). Other sarcomas, such as malignant peripheral nerve sheath tumors, fibrosarcoma, leiomyosarcoma, liposarcoma, and myxofibrosarcoma, exhibited no expression (n=0). These findings are consistent with previous research and support MUC4 specificity as a SEF and LGFMS marker. This study provides information on the diagnostic efficacy of MUC4, particularly in the context of certain subtypes. It not only helps our understanding of these unique instances, but it also provides context for histopathological and IHC findings in soft tissue sarcoma. Furthermore, this study investigates the influence of age and gender on MUC4 expression in a range of sarcomas, which was typically understudied in the literature and found no relation with expression of MUC4. Conclusion In conclusion, this study adds to our understanding of soft tissue sarcomas by emphasizing the crucial role of MUC4 in certain sarcoma subtypes while acknowledging the complex variety of the sarcoma landscape. Further research is needed to understand the molecular mechanism that governs marker expression patterns, as well as the therapeutic implications.

Primary lipoblastic nerve sheath tumor in an inguinal lymph node mimicking metastatic tumor: a case report and literature review

Lipoblastic nerve sheath tumors of soft tissue are characterized as schwannoma tumors that exhibit adipose tissue and lipoblast-like cells with signet-ring morphology. They have been documented to arise in various anatomic locations, including the thigh, groin, shoulder, and retroperitoneum. However, to our knowledge, this tumor has not been previously reported as a lymph node primary. We present herein the first case of a benign primary lipoblastic nerve sheath tumor arising in an inguinal lymph node in a 69-year-old man. Microscopic examination revealed a multinodular tumor comprising fascicles of spindle cells, as well as adipocytic and lipoblast-like signet-ring cell component in the context of schwannoma. Despite the presence of some bizarre cells with nuclear atypia, no obvious mitotic activity or necrosis was observed. Immunohistochemical analysis showed strong and diffuse expression of S-100, SOX10, CD56, and NSE in the spindle cells as well as in the signet-ring lipoblast-like cells and the mature adipocytes. Sequencing analysis of the neoplasm identified six non-synonymous single nucleotide variant genes, specifically NF1, BRAF, ECE1, AMPD3, CRYAB, and NPHS1, as well as four nonsense mutation genes including MRE11A, CEP290, OTOA, and ALOXE3. The patient remained alive and well with no evidence of recurrence over a period of ten-year follow-up.

Multispectral Imaging Analysis of Skin Lesions in Patients with Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is a rare disease, affecting around 1 in 3500 individuals in the general population. The rarity of the disease contributes to the scarcity of the available diagnostic and therapeutic approaches. Multispectral imaging is a non-invasive imaging method that shows promise in the diagnosis of various skin diseases. The device utilized for the present study consisted of four sets of narrow-band LEDs, including 526 nm, 663 nm, and 964 nm for diffuse reflectance imaging and 405 nm LEDs, filtered through a 515 nm long-pass filter, for autofluorescence imaging. RGB images were captured using a CMOS camera inside of the device. This paper presents the results of this multispectral skin imaging approach to distinguish the lesions in patients with NF1 from other more common benign skin lesions. The results show that the method provides a potential novel approach to distinguish NF1 lesions from other benign skin lesions.

MPNST of the abdominal wall in a patient with lynch syndrome: A case report of a rare presentation and unique association

INTRODUCTION

The abdominal wall is an extremely rare location for malignant peripheral nerve sheath tumors (MPNSTs). Besides presenting a rare location of MPNST, the peculiarity of our case lies in its association with Lynch syndrome, which is to our knowledge the first reported case of its kind.

PRESENTATION OF CASE

We present a case report of a 39-year-old male with a personal history of colonic cancer. Genetic counseling revealed Lynch syndrome with a heterozygous germline mutation in MLH1. Nine years after the right hemicolectomy, the patient presented with an asymptomatic lump in the abdominal wall. CT imaging showed a 3 cm mass in the aponeurosis of the right external oblique muscle. The patient underwent successful resection of the parietal tumor. Pathological examination revealed an MPNST. No additional treatment was warranted, and the patient exhibited no signs of relapse during the six months following the surgery.

DISCUSSION

MPNSTs of the anterior abdominal wall are extremely rare and challenging. Some studies have investigated the presence of mismatch repair (MMR) deficiency in patients with sarcomas. Our case consolidates the hypothesis of an association between sarcomas and Lynch syndrome, which raises the question of the efficacy of immune checkpoint inhibitor therapy in these cases where treatment options remain limited.

CONCLUSION

It is essential to have a deep understanding of the growth patterns of MPNSTs in the context of syndromes that predispose individuals to tumors, like Lynch syndrome. This knowledge is crucial for accurately predicting patient outcomes and developing appropriate plans for monitoring and treatment.

Small biopsies in the head and neck: Bone and soft tissue

Bone and soft tissue lesions in the head and neck encompass not only a broad morphologic spectrum but also significant inherent clinicopathologic overlap. Epidemiology, radiology, and location - similar to the diagnostic assessment in other sites - are especially important considerations in the context of an established mesenchymal proliferation. Herein, the approach towards diagnosis is stratified by morphology (spindle, sarcomatoid, epithelioid, round cell), cellular lineage (fibroblastic, nerve sheath, rhabdomyogenic), and tumor grade (benign, low- to high-grade malignant) as the basis of further immunohistochemical or molecular investigation.

Rare Benign Tumors and Tumor-like Lesions of the Hand without Skin Damage-Clinical, Imagistic and Histopathological Diagnosis, Retrospective Study

BACKGROUND

The broad spectrum of diagnoses and clinical features of hand tumors and the absence of pathognomonic signs often lead to an inaccurate or delayed diagnosis. However, only a few reports have comprehensively referenced the diagnosis and clinical features of hand tumors. This study intends to highlight the clinical, imaging and histological characteristics of uncommon hand tumors or tumor-like lesions.

METHODS

In this retrospective study, we report a series of 80 patients diagnosed with rare hand tumors and tumor-like lesions without skin damage. Age, gender, tumor location, imaging examinations and clinical and laboratory findings were analyzed. The histopathological exam established the final diagnosis. Surgery was indicated and performed in all cases.

RESULTS

This study included: neurofibroma, glomus tumor, lipoma, schwannoma, epidermal inclusion cyst and idiopathic tenosynovitis with "rice bodies." We have described the clinical, imagistic and histopathological particularities of these tumors. Surgical management included the complete removal of tumors, with no recurrence recorded within two years and overall high patient satisfaction. The most common findings were lipomas and the rarest neurofibromas.

CONCLUSIONS

To optimize the care of hand tumors and reduce diagnostic and treatment errors, knowledge of hand tumor types and their clinical and laboratory characteristics is necessary for every surgeon.

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.

Ankle Swelling in Patients With Type 1 Neurofibromatosis: A Report of Two Cases With Rare Presentation of Common Genodermatosis

Neurofibromatosis type 1 is characterized by multiple cutaneous neurofibromas of varying sizes along with skeletal, neurologic, and ophthalmic features. Solitary swellings in neurofibromatosis type 1 are not commonly encountered except in the form of plexiform neurofibromas. We report two cases with neurofibromatosis type 1 presenting with solitary swelling in the ankles which were proven to be the diffuse type of neurofibroma, radiologically and histopathologically. Diffuse type neurofibroma presenting as ankle swelling in type 1 neurofibromatosis has not been reported before.