Nerve sheath myxoma masqueraded as intramuscular myxoma: an extremely rare tumor with unusual location - a case report and literature review.

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.

PRAME expression in cellular neurothekeoma: A study of 11 cases.

BACKGROUND: Preferentially expressed antigen in melanoma (PRAME) has been widely investigated in the skin, mainly in melanocytic tumors, and constitutes an aid in differentiating benign from malignant lesions. Very few studies have been performed on non-melanocytic tumors. MATERIALS: We investigated the immunohistochemical expression of PRAME on a series of 11 neurothekeomas (NTKs), together with 3 cases of nerve sheath myxoma (NSM) and 1 case of plexiform fibrohistiocytic tumor (PFT), in order to evaluate the presence and usefulness of this marker in their differential diagnosis. RESULTS: PRAME was variably expressed in all cases of NTK, with moderate intensity in three cases and faint in the remaining cases; on the contrary, cases of NSM and PFT were negative. CONCLUSIONS: This study expands the entities of cutaneous non-melanocytic tumors expressing PRAME, and confirms that this marker is not restricted to malignant tumors. Expression of PRAME in NTK does not seem to be related to distinctive histopathologic features.

Intradural Extramedullary Nerve Sheath Myxoma of the Cervical Spine: A Case Report and Review of Literature.

Background: Nerve sheath myxoma is a rare benign soft tissue tumor. Intraspinal nerve sheath myxomas are rare. Only 8 cases of intraspinal nerve sheath myxoma have been reported to date, and no case of nerve sheath myxoma has been reported in the cervical spinal canal. Herein, we reported the first case of intradural extramedullary nerve sheath myxoma in the cervical spinal canal of a 57-year-old man, including its complete clinical course and radiological findings. Case Presentation: A 57-year-old male patient presented with numbness in his left finger without any obvious inducement for 3 years. CT and contrast-enhanced magnetic resonance imaging (MRI) of the spine were performed. Based on the radiological examinations, a diagnosis of schwannoma was initially made. However, nerve sheath myxoma was finally confirmed by histopathological and immunohistochemical examinations. Complete tumor excision at the C1-2 level was performed. Then, the patient recovered well, and the numbness of his left finger disappeared during the later follow-up after the surgery. Conclusion: Nerve sheath myxoma should receive diagnostic consideration for an extramedullary subdural lesion that is a clear boundary mass characterized by isointensity on T1-weighted images, heterogeneous intensity on T2-weighted images, obvious peripheral enhancement, and a growing tendency toward the intervertebral foramen.

Nerve Sheath Myxoma: A rare tumor, a case report and literature review.

INTRODUCTION: Nerve Sheath Myxoma is a rare benign nerve sheath tumor, commonly seen in young adults. Patients usually present with a small nodule commonly affecting upper and lower limbs. Nerve Sheath Myxoma has not been reported in children below the age of 1 year. CASE PRESENTATION AND METHODS: We present the first reported case of Nerve Sheath Myxoma (NSM) in the hand in a 4-month old child in line with the SCARE 2018 criteria. DISCUSSION: NSM is difficult to diagnose using standard imaging technique; Magnetic Resonance Imaging (MRI) and Ultrasonography (USS) cannot differentiate it from vascular anomalies. CONCLUSION: Soft tissue tumors in the hand of pediatric population are difficult to diagnose. Formal excision of the tumor by a specialized pediatric hand surgeon and histopathological analysis were the only avenue to correctly diagnose the NSM.

A Case Report of a Nerve Sheath Myxoma of the Lower Eyelid in a Young Male.

Myxomas are rare, benign tumors of uncertain etiology. Based on the published data, there have been few reported cases of eyelid nerve sheath myxomas and two cases of orbital myxomas. Eyelid nerve sheath myxomas have a similar presentation to neurothekeoma of the myxoid variety, and historically these two diagnoses have been considered interchangeable. At present, the proper diagnosis can be found through protein immunoreactivity with histological staining. Currently in published literature, there has not been documentation of a family history with eyelid growth in patients diagnosed with nerve sheath myxomas. In this case report, we present a 19-year-old male with a potential third recurrence of nerve sheath myxoma who reports a family history of similar eyelid lesions.

Neurothekeoma: Report of two cases in children and review of the literature.

Neurothekeomas, or simply nerve sheath myxomas, are rare benign skin neoplasms. They are believed to derive from peripheral nerve sheath transformation and are typically more prevalent in females. They tend to be found mainly on the upper limbs as well as head and neck locations. In this report, we detail two children with neurothekeomas, describe the fundamental clinical manifestations, and review the current literature.

Neurothekeoma of the eye, conjunctiva, and periorbital adnexa: A report of two cases and brief review.

Neurothekeomas (NTKs) are benign soft tissue tumors most commonly occurring in the head, neck, and upper extremities of young adults, with a female preponderance. Herein, we report 2 cases of ocular NTK presenting as an orbital mass or chalazion. Both cases underwent excision of the mass with histopathologic diagnosis of cellular NTK. Tumor cells for both cases were immunopositive for smooth muscle actin, microphthalmia-associated transcription factor, and cluster of differentiation 10. S100, human melanoma black 45, and melanoma antigen recognized by t-cell (Melan A) were negative. Both were associated with scattered histiocytes, which were positive for cluster of differentiation 68. To date, including our 2 cases, there have been 22 cases of ocular and periorbital adnexal NTK reported in the English-language literature. Although rare, clinicians should include NTK in their differential diagnosis in patients presenting with a periocular soft tissue tumor.

Nerve sheath myxoma of the oral cavity: a distinct entity.

Nerve sheath myxomas (NSM) are uncommon benign tumours of nerve sheath origin. These tumours are most often located in the dermis and subcutaneous tissue of the head and neck region, but less frequently can also involve extracutaneous sites but they are rarely seen in the oral cavity. Many authors consider nerve sheath myxoma and neurothekeoma to be variants of the same tumour, though currently it has been demonstrated that both the lesions are distinct entities with different origins and unique morphological features. Herein we report a case of Nerve Sheath Myxoma on the palatal gingiva.

Oral nerve sheath myxoma: a rare and unusual intraoral neoplasm.

We present a rare case of intraoral nerve sheath myxoma. Clinically, the neoplasm mimics many other oral mucosal pathosis, underscoring the importance of histopathology in ensuring accurate diagnosis of oral mucosal lesions. Reports of intraoral nerve sheath myxomas are essential to enhance our understanding of this rare intraoral entity.

Neurothekeoma of the Cornea.

Neurothekeomas (NTKs) are benign cutaneous neoplasms of fibrohistiocytic origin and most commonly occur in the head, neck, and upper extremities. Traditionally, NTK and nerve sheath myxoma (NSM) were classified as subtypes of a single neoplasm with a common histogenesis, but recently immunostaining has demonstrated that the lesions are most likely of distinct cellular origin. Rarely, NTKs have been reported to occur in the ocular adnexa, and the present case of a 39-year-old female is the first to describe a cellular NTK originating in the cornea and mimicking a Salzmann's nodular degeneration. This report describes the clinical and pathological findings of the patient, discusses the changes in the classification of these rare neoplasms in light of advances in immunohistochemistry, and reviews all cases of ocular NTK found in the literature.

Cellular Neurothekeoma of the Scalp in the Elderly.

Cellular neurothekeoma (CNT) is an uncommon variant of neurothekeoma that is composed of pithelioid to spindled cells with variable nuclear atypia or pleomorphism but no myxoid stroma. CNT occurs predominantly in the head and neck or upper trunk of children and young adults, with female predominance. The following case is different from typical CNTs. An 88-year-old female presented with a palpable mass on the scalp, which we excised. Histologically, the tumor was non-encapsulated and composed of spindled and epithelioid cells arranged in fascicles and nodules separated by a collagen-rich stroma. Immunohistochemical analysis showed that the epithelioid and spindle-shaped cells were focally positive for vimentin, neuron-specific enolase, smooth muscle actin, CD68, and CD10 but negative for S-100 protein, HMB-45, epithelial membrane antigen, and CD34. We report a new case of CNT that arose in the scalp of an older patient and that was associated with uncommon clinical, histological, and immunohistochemical profiles.

Cellular Neurothekeoma of the Scalp in the Elderly

Cellular neurothekeoma (CNT) is an uncommon variant of neurothekeoma that is composed of pithelioid to spindled cells with variable nuclear atypia or pleomorphism but no myxoid stroma. CNT occurs predominantly in the head and neck or upper trunk of children and young adults, with female predominance. The following case is different from typical CNTs. An 88-year-old female presented with a palpable mass on the scalp, which we excised. Histologically, the tumor was non-encapsulated and composed of spindled and epithelioid cells arranged in fascicles and nodules separated by a collagen-rich stroma. Immunohistochemical analysis showed that the epithelioid and spindle-shaped cells were focally positive for vimentin, neuron-specific enolase, smooth muscle actin, CD68, and CD10 but negative for S-100 protein, HMB-45, epithelial membrane antigen, and CD34. We report a new case of CNT that arose in the scalp of an older patient and that was associated with uncommon clinical, histological, and immunohistochemical profiles.

Cellular Neurothekeoma of the Scalp in the Elderly

Cellular neurothekeoma (CNT) is an uncommon variant of neurothekeoma that is composed of pithelioid to spindled cells with variable nuclear atypia or pleomorphism but no myxoid stroma. CNT occurs predominantly in the head and neck or upper trunk of children and young adults, with female predominance. The following case is different from typical CNTs. An 88-year-old female presented with a palpable mass on the scalp, which we excised. Histologically, the tumor was non-encapsulated and composed of spindled and epithelioid cells arranged in fascicles and nodules separated by a collagen-rich stroma. Immunohistochemical analysis showed that the epithelioid and spindle-shaped cells were focally positive for vimentin, neuron-specific enolase, smooth muscle actin, CD68, and CD10 but negative for S-100 protein, HMB-45, epithelial membrane antigen, and CD34. We report a new case of CNT that arose in the scalp of an older patient and that was associated with uncommon clinical, histological, and immunohistochemical profiles.

Nerve sheath myxoma: report of a rare case.

Nerve sheath myxoma defined by Harkin and Reed is an uncommon benign neoplasm with nerve sheath like features. It has several cytological and histological differential diagnoses. One such lesion is neurothekeoma, which can be differentiated using immunohistochemistry. In most of the previous reports nerve sheath myxoma and neurothekeoma were considered synonymous and were often confused for one another. This case report separates the two using immunohistochemistry. Also, the cytological features of nerve sheath myxoma are not well documented in the past. This case report attempts to display the cyto-morphology of nerve sheath myxoma. We report a rare case of nerve sheath myxoma diagnosed on cytological features confirmed by histopathology and immunohistochemistry in a 32-year-old lady who presented with an asymptomatic nodule over the left cervical area and discuss its cyto-histological mimics.

Orbital nerve seath myxoma with extraocular muscle involvement: a rare case.

A 66-year-old woman with breast cancer presented with a painless mass in the left orbit. MRI revealed a well-defined intraconal mass in the temporal quadrant of the orbit. Fifteen months later, a further MRI indicated the mass had grown, displacing the left optic nerve and making contact with the lateral rectus muscle, suggesting its possible intramuscular origin. Despite the clinical and radiological characteristics of the lesion and its slow growth, a PET/CT study was developed because of the history of malignant disease. No metabolic activity of the mass or malignant lesion in other locations was observed. After surgical excision, histopathological examination revealed an abundant myxoid matrix with few spindle-shaped cells and no signs of malignancy. The cells were immunopositive for CD34, positive for S-100 protein, and negative for EMA, actin, and CD57. A diagnosis was made of a nerve sheath myxoma. The orbital location of these tumors is extremely rare.

Neurotecoma celular, localización lingual: presentación de caso clínico en el postgrado de cirugía plástica y reconstructiva del Instituto Autonómo Hospital Universitario de los Andés / Cell neurotecoma, location lingual: presentation of a clinical case in the postgraduate studies on plastic and recontructive surgery at the Instituto Autonómo Hospital Universitario de los Andés-Mérida-Venezuela

El Neurotecoma Celular es un raro tumor benigno de histopatogénesis incierta extremadamente atípico. Clínicamente la lesión es poco característica, generalmente es un nódulo solitario asintomático de crecimiento lento que se puede presentar en piel y mucosas. El diagnóstico se basa en los hallazgos histológicos y de inmunohistoquímica, se considera que los neurotecomas en sus distintas variantes: mixoide, celular o mixta forman parte de un espectro de tumores con un supuesto origen en la vaina nerviosa, sin embargo numerosos autores afirman que se trata de tumores diferentes que justifican una clasificación separada. A nivel mundial existen tan solo alrededor de 300 reportes de este tipo de tumoración, por ello el interés de presentar el caso de un paciente masculino de 13 años de edad quien ingreso y fue tratado por el servicio de cirugía plástica y reconstructiva del hospital universitario de los andes y quien curso con una neoformación de aproximadamente 30mm de diámetro, firme, de crecimiento lento, localizada en la porción del margen derecho de la lengua con 14 meses de evolución. El diagnóstico histopatológico confirmó un Neurotecoma Celular(AU)

The Cell Neurothekeoma is a rare benign tumor of uncertain histopatogenesis extremely atypical. Clinicallyncharacteristic lesion, usually an asymptomatic solitary nodule of slow growth. It can occur in the skin and mucous membranes. The diagnosis is based on histological and immunohistochemically findings, the neurotecomas are considered that in its different considered that in its different variants: myxoid, mixed cell or mixed, are a part of putative origin tumors in the nerve sheath, however many authors claim that this are different tumors that justify a separate classification. Worldwide there are only about 300 reports of this type of tumor so the interest of presenting the case of a male patient of 13 years old who income and was treated by the service of plastic and reconstructive surgery at the Andes University Hospital and he coursed with a new formation of approximately 30mm diameter, firm, slow-growing, located in the right lateral portion of the tongue with 14 months duration. Histopathological diagnosis confirmed a Cell Neurothekeoma(AU)

SOX-10 and MiTF expression in cellular and 'mixed' neurothekeoma.

BACKGROUND: Neurothekeoma and nerve sheath myxoma have long been interpreted as related tumors that share nerve sheath linage. Lack of S100 expression in neurothekeoma and similarities of gene expression profiles between neurothekeoma and fibrohistiocytic tumors have created reasonable doubt about this concept. SOX-10 represents a marker for schwannian and melanocytic differentiation, and is expressed in other tumors of nerve sheath linage. Microphthalmia transcription factor (MiTF) expression has been repeatedly reported in cellular neurothekeoma in the recent literature and was proposed as a helpful marker in this entity. METHODS: We investigated 25 cases of cellular neurothekeoma, 8 cases of mixed neurothekeoma and 1 case of nerve sheath myxoma for the expression of SOX-10, MiTF, S100, NKI/C3, Melan-A and smooth muscle actin (SMA) using immunohistochemistry. RESULTS: A lack of SOX-10 expression was demonstrated in 100% of cellular and mixed neurothekeomas, but was present in the case of nerve sheath myxoma. More than two thirds of neurothekeomas showed very focal or no reactivity with MiTF. CONCLUSIONS: Our data suggest that neurothekeoma and nerve sheath myxoma are unrelated, and that cellular and mixed neurothekeoma may not be of nerve sheath lineage. In addition, MiTF should not be regarded as a useful marker in neurothekeoma.

Palmar Nerve Sheath Myxoma: A Case Report.

Nerve sheath myxoma is a rare benign tumor of the peripheral nerves. It typically presents as a painless, firm, and slow growing nodule with a predilection for extremities mostly fingers and knees. Microscopically, it has characteristic multilobules of spindle cells in an abundant myxoid stroma. The cells are strongly positive for S-100 protein. However, this rare tumor is usually misdiagnosed as other more common benign neuronal tumors. This report describes a rare case of nerve sheath myxoma involving the palmar surface of a 23-year-old female. Clinically, it was diagnosed as a fibroma. It was excised and the final diagnosis was made after histopathological and comprehensive immunohistochemical examination of the specimen. The clinicopathological features of this rare tumor and its important differential diagnoses are discussed along with a brief review of the literature.

Neurothekeoma palpebrae in association with multiple superficial angiomyxomas: Tegumental Angiomyxoma-Neurothekeoma syndrome (TAN syndrome).

We report a case of 10-year-old Indian girl with history of multiple superficial angiomyxoma, presented with three months history of painless right upper lid swelling. There were no visual dysfunctions. Previously, the patient had multiple superficial angiomyxoma (left pinna, left upper cheek, left upper limb, chest, right axilla, hard palate) and epidermal cyst (chin). The histopathological specimens were negative to S-100 protein antibody. Systemic review and family history was unremarkable. Excision biopsy and upper lid reconstruction were performed. Intraoperatively the tumor was multilobulated, firm, well encapsulated and did not invade the underlying tarsal plate. Histopathological features of the upperlid tumor were consistent with nerves sheath myxoma (neurothekeoma). To the best of the authors' knowledge, this is the first reported case of neurothekeoma in association with multiple superficial angiomyxoma.