Nerve sheath myxoma: A rare myxoid tumour with schwannian differentiation

Cellular neurothekeoma is an uncommon dermal neoplasm that frequently overlaps histologically with fibrohistiocytic and melanocytic tumors, particularly in superficial or limited biopsies. MiTF immunohistochemistry is commonly used for diagnostic support but shows inconsistent sensitivity with variable and often focal expression patterns, which can complicate interpretation. Cyclin D1 is a widely available nuclear marker expressed in some related fibrohistiocytic tumors, but its performance in cellular neurothekeoma has not been studied. Eleven cellular neurothekeomas diagnosed over a 7-year period were identified. Immunohistochemistry for cyclin D1 and MiTF was performed on formalin-fixed, paraffin-embedded tissue. Slides were independently scored using the blue-brown color H-score method, including assessment of overall H-scores and the proportion of tumor nuclei staining at ≥ 2+ intensity. Cyclin D1 showed consistently strong nuclear expression in all cases (11/11, 100%), with a median H-score of 205 (IQR 200-222.5), compared with 40 for MiTF (IQR 27.5-115) (p < 0.001). Strong (≥ 2+) nuclear staining was present in a median of 90% of tumor cells with cyclin D1 (IQR 82.5-100), versus 10% with microphthalmia transcription factor (IQR 0-35) (p < 0.001). MiTF wasinterpreted as positive in fewer than half of cases (5/11, 45%). Cyclin D1 demonstrated uniform, strong nuclear expression and superior sensitivity compared with MiTF, supporting its use as a sensitive and dependable immunohistochemical marker for cellular neurothekeoma.

To date our knowledge of the genomic landscape of cellular neurothekeoma (cNTK) remains incomplete. Thus, in order to comprehensively elucidate the mutational profile of this rare tumour type and identify driver events, we sequenced DNA (whole-exome sequencing) and RNA (pulldown transcriptome) from an international, multi-institutional cohort of cNTK tumour-normal pairs (n = 20). We identified copy number (CN) alterations as a driver event of this tumour type, with the most recurrent CN alteration being a deletion on 9p21.3 that encompassed MTAP and the C-terminal exons of CDKN2A.

ALK Expression in Nerve Sheath Myxoma: A Potential Diagnostic Pitfall.

Myxoid neurothekeoma, also known as nerve sheath myxoma, is a rare benign peripheral nerve sheath tumour primarily reported in mammals, with scarce documentation in teleost fishes. This study reports a confirmed case of myxoid neurothekeoma in the Indian oil sardine (Sardinella longiceps ), a commercially significant marine species along India's southeast coast. An adult female specimen exhibiting a fleshy, dome-shaped, slightly pale brownish mass on the dorsal head was examined grossly and subjected to histopathological analysis using haematoxylin and eosin, Alcian blue and Masson's trichrome staining. Immunohistochemical staining for S100 protein confirmed the neural origin of the tumour cells. Microscopic analysis revealed a well-circumscribed lobular neoplasm composed of spindle to stellate cells within a myxoid stroma rich in acid mucopolysaccharides. Tumour lobules were separated by thin collagenous septa, and widespread S100 positivity supported Schwann cell lineage. The lack of mitotic activity, cytological atypia or invasive features supported a diagnosis of benign myxoid neurothekeoma. This case expands the current understanding of peripheral nerve sheath tumours in marine teleosts and contributes to the broader characterisation of rare neoplasms in aquatic species.

Nerve sheath myxoma (NSM) is a rare benign tumor originating from peripheral nerves. We present a case of NSM in the upper extremity. A 67-year-old female presented with painful nodular bulging in the elbow. Magnetic resonance imaging and ultrasonography revealed diagnostic features. Surgical excision was performed and histopathological examination confirmed the diagnosis. Our case contributes to the understanding of NSM's clinical presentation, imaging characteristics, and management strategies of NSM.

Metastatic cellular neurothekeoma arising over a vaccination scar: A case report and literature review.

Dear Editor, Neurothekeoma is a rare, benign, soft tissue tumor that primarily affects the dermis. Initially described as a variant of nerve sheath myxoma, it was later recognized as a distinct entity because of its histopathological and immunohistochemical differences, as it is thought to be derived from fibroblast. It is most commonly observed in children and young adults, is more frequent in females, and typically arises in the head, neck, and upper extremities. [...].

We incidentally observed CD138 (syndecan-1) expression in a cellular neurothekeoma (CNT) and sought to investigate whether this is a consistent finding in these tumors. We evaluated a series of 20 skin biopsy specimens diagnosed as CNT for CD138 immunohistochemical staining in comparison to the more traditional CNT immunohistochemical stains, NKI/C3 and MITF. Control cases of xanthogranuloma (XG), dermal Spitz nevi, and epithelioid fibrous histiocytomas (EFH) were included based on similar histopathologic morphology. CD138 expression in a membranous and reticulated extracellular pattern was observed in 95% of CNT cases evaluated. NKI/C3 was expressed in 83% of CNT, and MITF in 72%. Of the control cases, 10% of XG, 10% of dermal Spitz nevi, and 17% of EFH expressed CD138. Our data suggest that CD138 may be a useful adjunctive marker in the diagnosis of CNT, particularly when utilized in a panel with other established markers such as NKI/C3 and MITF.

This case report discusses a rare instance of Nerve Sheath Myxoma (NSM), a benign tumour originating from peripheral nerve Schwann cells. While typically found in the distal extremities, this case involved a 10-year-old girl with a mass in the parotid region, presenting a unique challenge in diagnosis. Initial clinical assessments suggested a benign salivary gland tumour, but inconclusive FNAC results and conflicting CE-MRI findings led to the excision of the lesion. Histopathological examination revealed a well-circumscribed, multinodular hypocellular myxoid tumour consistent with NSM. Immunohistochem istry confirmed the diagnosis, showing positivity for S100, EMA, Vimentin, and CD34. This study highlights the importance of immunohistochemistry in differentiating NSM from other entities, particularly neu rothekeoma. The treatment of choice is wide local excision with tumour-free margins, and while local recurrences are reported, malignant transformation is undocumented. In conclusion, clinical and imaging techniques may struggle to accurately identify NSM, necessitating reliance on histopathology and immunohistochemistry for diagnosis.

Cellular Neurothekeoma – Rare but exists

Atypical cellular neurothekeoma is a rare benign soft-tissue tumour that usually arises in the head and neck region, shoulder girdles, and proximal extremities, predominantly in young women. This dermal neoplasm is under-reported in the literature and is not uncommonly misdiagnosed as a malignant tumour due to its worrisome histologic characteristics. Currently, the diagnosis of cellular neurothekeoma relies on a panel of non-specific immunohistochemical markers and its etiopathogenesis is unknown.Herein, we present the case of an atypical cellular neurothekeoma in the arm of a 49-year-old woman, describing its microscopic features and immunohistochemical profile. Additionally, we present a novel heterozygous predicted inactivating NF1 mutation, not previously reported, which was identified using high-throughput molecular techniques. Such finding might provide insights into the pathogenesis of neurothekeoma, potentially contributing to future refinements in diagnosis, which would enable more precise identification of this neoplasm.

Abstract Ectomesenchymal chondromyxoid tumor is a very rare tumor, which mostly occurs in the tongue. Here, we are presenting a case of a 55-year-old man with a swelling in the anterior dorsum of his tongue. The mass was excised and subsequent histopathological examination revealed a subepithelial well-circumscribed mass comprising oval to fusiform tumor cells, arranged in sheets, whorls, and reticular pattern within a prominent chondromyxoid stroma. The tumor cells were positive for glial fibrillary acidic protein, S100, and vimentin, whereas negative for epithelial membrane antigen and p63 on immunohistochemistry. These tumors have to be differentiated from other myxoid lesions, such as oral focal mucinosis, nerve sheath myxoma, soft tissue myxoma, glial choristoma, and ossifying fibromyxoid tumor of soft parts.

CELLULAR NEUROTHEKEOMA WITH PROMINENT MYXOID STROMA IN THE ORAL CAVITY: A DIAGNOSTIC CHALLENGE.

We report a case of cellular neurothekeoma (NTK) in a 4-year-old male boy, which presented as a painless, progressive, left upper lid mass of 6 months’ duration. The left upper lid mass was solitary and dome shaped, causing mechanical ptosis. A magnetic resonance imaging (MRI) was performed followed by surgical excision of the mass in two stages, which, after histopathology and immunohistochemistry, was confirmed to be cellular NTK with no recurrence reported so far. To our knowledge, cellular NTK (a variant of NTK), an uncommon benign skin neoplasm involving the ocular adnexa (eyelid), is extremely rare. It is important to differentiate it from other malignant lesions, so that aggressive treatment can be avoided. The treatment of choice in cellular NTK is complete excision with clear margins.

Nerve sheath myxoma is a rare benign tumor of peripheral nerve sheath origin arises from the Schwann cell. In 1969 Harkin and Reed first reported a case of Nerve sheath myxoma. The benign tumor clinically present as a nodular soft tissue swelling. Microscopic features are well circumscribed, varying sized nodules comprising of stellate cells in a myxoid background. The cells show diffuse positivity for S100. Nerve sheath myxoma to be differentiated from Neurothekoma, Myxoid Neurofibroma, Myxoid Schwannoma and Perineuroma.

Myxomas in the oral cavity and lips are relatively uncommon tumors that present in different types: the first type is odontogenic myxomas and the second type is soft tissue myxomas. Odontogenic myxomas (originated from the mesenchymal cells of the oral cavity such as dental papillae, periodontium, or dental follicles) are most presented in the maxilla and mandible. In comparison, soft tissue myxomas are rare in the oral cavity and lips, and only 30 cases of unknown development were reported in the literature, and only five cases involving the lip were reported. Even if it is considered very rare, nerve sheath (soft tissue) myxoma must be included in the differential diagnosis of lip lesions and excised widely to prevent local recurrence. The aim of our case study is to present a rare case of lip myxoma in a male patient 26-year-old who presented with a soft, exophytic lesion on the lower lip.

Nerve sheath myxoma (NSM) is a rare myxoid form of schwannoma, which is a benign tumor that usually grows in the same place. They usually arise from small cutaneous nerves in the head, neck, and extremities, but exceptionally, they have also been reported to develop in the spinal canal. Here we describe a case of spinal NSM. The patient was a 4-month-old male who presented with incomplete tetra paresis. Spine magnetic resonance imaging showed a well-demarcated small intradural extramedullary mass at the T10-L1 level. The tumor has typical histological features of myxoid type NSM with myxoid lobules that are separated by fibrous septa or bands of more compact cellular area. Nerve sheath myxomas should be included in the differential diagnosis of spinal canal tumors. Ultrastructural observation of tumor cefis with perineurial, fibroblast-like, and Schwann differentiation suggests an origin from nerve sheath precursor cefis.

Background:Nerve sheath myxoma (NSM) is a very rare benign nerve sheath tumor that mostly affects young adults, with a peak incidence in the 30s. Patients usually present with an asymptomatic swelling commonly affecting the dermis and subcutaneous tissues of the head, neck, and upper extremities. Lower extremities are a much rarer location, and when this occurs, the knee/pretibial region is the most common location. NSM has not been reported within the anterior tibialis muscle.Case Presentation:The authors present the first reported case of NSM in the anterior tibialis muscle in a 39-year-old man presented as deep swelling in the left leg.Discussion:NSM is difficult to diagnose clinically or using standard imaging techniques; MRI and ultrasonography cannot differentiate it from other anomalies. Histopathology alone is not enough to distinguish NSM from neurothekeomas, which were considered synonymous in the past. They can be distinguished by using immunohistochemical markers.Conclusion:Soft tissue tumors in lower extremity muscles are somewhat difficult to diagnose. Excision of the tumor by a specialized orthopedic surgeon and histopathological/immunohistochemical analysis were the only avenues to correctly diagnose the NSM.

32748 A case series of pediatric cellular neurothekeomas and a review of the histologic spectrum