A Rare Case of Subconjunctival Nerve Sheath Myxoma Presenting as Orbital Fat Prolapse.

Nerve sheath myxomas are extremely rare myxoid peripheral nerve sheath tumors with a predilection for the distal extremities, particularly common in the fingers and knees. Here, the authors report a 60-year-old male patient with a subconjunctival epibulbar nerve sheath myxoma, which was clinically diagnosed as an orbital fat prolapse. The lesion was successfully debulked without clinical recurrence over more than 3 years. To the authors' knowledge, this is the first case with subconjunctival presentation and fourth orbital reported case.

Nerve Sheath Myxoma in the Lower Extremity: A Rare Case with Description of Magnetic Resonance Imaging and Sonographic Findings.

BACKGROUND This report is of a nerve sheath myxoma presenting as a slow-growing mass in the back of the left ankle of a 36-year-old man that was investigated by ultrasound and magnetic resonance imaging (MRI) before the diagnosis was confirmed by histopathology. CASE REPORT We report a nerve sheath myxoma of the ankle in a 36-year-old man. The palpable abnormality was falsely assumed to be a ganglion cyst prior to advanced imaging. Magnetic resonance imaging demonstrated a lobular mass with high T2 and intermediate T1 signal as well as moderate enhancement. T2 sequences also demonstrated distinctive internal septae. These internal septae were also noted on sonographic evaluation prior to biopsy. The patient was treated with surgical excision, and pathologic analysis showed myxoid nodules with loose arrangements of spindled cells separated by fibrous septae. S-100 protein and glial fibrillary acidic protein positivity by immunohistochemistry staining was demonstrated. Follow-up imaging at 12 months showed no evidence of tumor recurrence. CONCLUSIONS This case highlights that while nerve sheath myxomas are rare tumors, they should be considered in cases of cutaneous soft-tissue masses with myxoid imaging features. Ultrasound and magnetic resonance imaging features of thin internal septae may be present and correspond well with the unique histopathological characteristics of these lesions. This report shows the importance of imaging of peripheral soft-tissue masses, including ultrasound and MRI, which can identify localized and benign features and the solid, cystic, and myxoid areas, which were characteristic in this case of benign nerve sheath myxoma.

Pediatric cellular neurothekeoma: Seven cases and systematic review of the literature.

BACKGROUND/OBJECTIVES: Neurothekeoma is a rare, benign, cutaneous neoplasm consisting of Schwann cells and perineural cells in myxoid stroma. Cellular neurothekeoma (CNT) was previously thought to represent a morphologic variant of neurothekeoma, but recent studies have shown that CNTs are unrelated to neurothekeomas and are more likely of histiocytic lineage. METHODS: Herein, we describe seven cases of CNT in pediatric patients. A comprehensive search of PubMed was performed, and 71 cases of cellular neurothekeoma in pediatric patients were reviewed. RESULTS: The clinical differential diagnosis for these lesions included Spitz nevi, keloid, juvenile xanthogranuloma, cutaneous lymphoid hyperplasia, and lymphomatoid papulosis. All cases were treated by excision or excisional biopsy. Histopathologically, all demonstrated multilobular, primarily intradermal neoplasms composed of plump spindled or epithelioid mononuclear cells with abundant eosinophilic pale-staining cytoplasm. Immunophenotypic findings included CD68 and NKI/C3 positivity, and negative staining with cytokeratin, S-100, Melan-A, and SOX-10. CONCLUSION: Cellular neurothekeoma is distinguished from conventional neurothekeoma by increased cellularity, a lack of myxoid stroma, and a lack of neural expression with immunohistochemical stains. These uncommon neoplasms should be included in the differential diagnosis of dermal nodules in children. Accurate diagnosis of these lesions is essential, as they can be mistaken for malignancy leading to unnecessary treatment.

Sleeve-Shaped Neurothekeoma of the Ulnar Nerve: A Unique Case of a Still Unclear Pathological Entity.

Background: Neurothekeomas are slow-growing, well-circumscribed benign neoplasms. They usually involve cutaneous or subcutaneous tissues. Although originally described as myxomas deriving from nerve sheath cells, their exact histological classification is still uncertain. Peripheral nerve localization is rarely reported. Here, we describe a unique case of sleeve-shaped neurothekeoma of the ulnar nerve, which was incidentally discovered during a cubital tunnel release surgery. Methods: A 57-year-old man was admitted at our institution with clinical, ultrasonographic, and electromyographic findings highly suggestive of cubital tunnel syndrome. During ulnar nerve decompression surgery, however, no bony or ligament compression was noticed, but a segment of the nerve wrapped by a thick sleeve-shaped tissue, which had no clear-cut cleavage plane from the nerve. Given this unexpected finding, the en bloc excision of the lesion was avoided. A nerve decompression with biopsy of the swelling portion of the lesion was performed instead. Results: Histological examination described abundant myxoid stroma, with epithelioid and ring-shaped cells arranged in cords, negative to S100 protein at immunohistochemical analysis. This pattern was suggestive of neurothekeoma. The patient showed improvement in hypermyotrophy and intrinsic weakness of the hand. Conclusions: To the best of our knowledge, this is the first report of a sleeve-shaped neurothekeoma of the ulnar nerve. The exact pathological characterization of such rare entities remains uncertain. In case of peripheral nerve localization, and when a clear cleavage plane is absent, the correct management of these lesions should be that of simple nerve decompression followed by biopsy.

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.

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.

Neurothekeoma in the middle cranial fossa as a rare location: Case report and literature review.

Neurothekeoma is a benign cutaneous nerve sheath tumor usually located in the head and neck region. To date, only a few cases of intracranial location have been reported in the literature. We report an extremely rare case of intracranial neurothekeoma located in the brain parenchyma of the middle cranial fossa. A 55-year-old female patient was operated on at our clinic for a right temporal cystic mass lesion with heterogenic contrast enhancement. Histologically, the tumor had a multinodular hypercellular appearance with a myxoid matrix, peripheral fibrosis, and sclerosis. It was characterized by spindle and epithelioid mononuclear cells, immunochemically positive with diffuse S-100, vimentin, GFAP, PGP 9.5, and NSE, as characteristics of cellular neurothekeomas. After a total surgical resection, there was no need for further adjuvant chemotherapy or radiotherapy. Because there were still unclear aspects regarding the origin, pathogenesis and management of the intracranial neurothekeomas, we decided to contribute to the literature with this case report.

Benign Nerve Sheath Myxoma in an Infant Misdiagnosed as Infantile Digital Fibromatosis.

Herein we present the case of a 16-month boy, clinically diagnosed with infantile digital fibromatosis, but 9 months after continued growth, the mass was excised and the histopathologic diagnosis was that of a benign nerve sheath myxoma. We present this case to emphasize that nerve sheath myxomas (also known as myxoid neurothekeoma) should be included in the differential diagnosis of dermal nodules in infants.

An unusual case of neurothekeoma of the arm in an adult.

Neurothekeomas are uncommon benign neoplasms with a peripheral nerve sheath origin. This tumor usually involves dermis and is described as a small, solitary, slow growing and reddish to flesh-colored nodule or papule. Neurothekeoma preferentially affects the central aspect of the face, the arms or shoulders of women in the second and third decades of life. This is the first case report of neurothekeoma involving the wrist developing from synovial tissue and with uncertain clinical behavior in an adult female. The tumor was completely excised under brachial plexus block. Histopathologically, the examination of the microscopic slides revealed the presence of a 20-mm diameter, well-circumscribed and multilobulated tumor composed of abundant myxoid stroma with cellular elements; with immunohistochemistry there was positivity to vimentin but S100-protein, epithelial membrane antigen, cytokeratin AE1-3, CD99 and CD34 were all negative. This pattern suggested a myxoid tumor form of neurothekeoma, mixed subtype. The patient had an atypical local recurrence and was re-operated after 3 months. After 12 months there was no evidence of clinical recurrences confirmed by magnetic resonance evaluation. Basically, our case report adds an important element in the correct clinical management of neurotecheomas: faced with a histological diagnosis with an unusual localization and mixed or hypercellular type, clinicians must consider the possibility of an early local recurrence, suggesting a close clinical and radiological follow-up.

A review of eight unusual pediatric skin and soft-tissue lesions: Diagnosis, workup, and treatment.

The spectrum of clinical presentations in pediatric skin and soft-tissue lesions often makes diagnosis challenging. Delays in diagnosis and subsequent treatment can be life threatening, and they can subject patients to more complicated reconstruction. This retrospective case series reviews the presentation, management, and current literature on eight pediatric skin and soft-tissue lesions. For rare lesions and those with unclear pathology, a multidisciplinary approach is strongly advocated for optimal management.

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.

Mediastinal neurothekeoma: a rare tumor.

Neurothekeoma, also known as nerve sheath myxoma, is a benign nerve sheath tumor that usually arises in the cutaneous nerves of the head, neck, or upper extremities. Extracutaneous placement is very rare. Mediastinal neurothekeoma has not previously been reported in the English literature. A 30-year-old woman was admitted to our clinic with back pain. A smooth-edged mass found in her paravertebral region, and a neurogenic tumor was suspected. The tumor was completely excised. Final pathology revealed it to be a mediastinal neurothekeoma.