Malignant epithelioid peripheral nerve sheath tumor arising in a benign schwannoma

Malignant peripheral nerve sheath tumors arising from schwannomas: case series and literature review

A malignant peripheral nerve sheath tumor (MPNST) arising from a schwannoma is extremely rare, with limited literature on its clinicopathologic features. Here, we present a case series and literature review on patients with MPNSTs arising from schwannomas. We performed a retrospective review of patients from our institution's records to identify those with MPNSTs arising from schwannomas. We conducted a search for additional cases from the literature utilizing PubMed. 20 patients (including 2 at our institution and 18 from 16 prior publications) were identified. The patients aged 22-93 (mean 52) years, and 63% were females. Histologically, while most MPNSTs arising from schwannomas were of epithelioid-type, 7 tumors (including 2 at our institution) were of conventional spindle-cell type. All 20 patients underwent surgical excision, while a subset received additional radiotherapy and/or chemotherapy. In 17 patients with available follow-up, the overall survival was 2-72 (median 12) months. MPNSTs rarely arise from schwannomas and should be considered in patients with a clinical diagnosis of schwannoma, however, with atypical radiologic or clinical features. MPNSTs arising from schwannomas can show epithelioid or spindle-cell histology and harbor an aggressive course, even with surgical excision and adjuvant treatment.

Retroperitoneal Malignant Schwannoma. A Case Report

The isolated retroperitoneal malignant schwannoma unassociated with Von Recklinghausen's disease is an unusual neoplasm, representing 0.01% of all retroperitoneal malignant neoplasms, with a poor prognosis, and an average survival at 5 years of 50% in patients treated by radical exeresis. At present, it is impossible, without histologic and immunohistochemical examinations, to differentiate it from other isolated retroperitoneal sarcomatous neoplasms. The authors report a case of retroperitoneal malignant schwannoma 20 cm in diameter in a 62-year-old woman surgically treated by radical exeresis. Postoperative complications were absent, and the patient, discharged from the hospital on the 12th postoperative day, died 8 months later of diffuse metastases, withouth local relapse. Despite the patient's short survival, the authors believe radical surgery to be the best therapeutic choice. Only surgery can establish a final diagnosis and can offer the best chance of survival and a significant and sometimes prolonged relief of symptomatology.

Malignant peripheral nerve sheath tumor of the orbit: case report and literature review

A 68-year-old woman with progressive visual loss and exophthalmos in her right eye had been operated on for a mass in her right calf 3 years earlier. Imaging showed a huge mass invading the orbital structures and temporal pole. The presumptive diagnosis was a malignant orbital tumor. The tumor was resected totally and eroded tissues such as the lateral rectus muscle and dural compartments were repaired. The histological diagnosis was a malignant peripheral nerve sheath tumor (MPNST). The patient recovered uneventfully and was discharged 8 days after surgery. Two years later she died from a liver tumor. Few MPNSTs involving the orbit have been reported.

[Intrathoracic vagal nerve schwannoma preoperative diagnosis is correct because of clinical and characteristic CT findings--a case report and review of the literature]

A 60-year-old man was operated with the clinical diagnosis of intrathoracic vagal nerve schwannoma because of characteristic CT findings and no symptom of neurofibromatosis. Thoracoscopic surgery was performed and it was confirmed pathologically. Intrathoracic vagal nerve tumor is rare, so preoperative diagnosis seems to be difficult. We review the intrathoracic vagal nerve tumors reported in Japan (52 cases of schwannoma and 9 cases of neurofibroma), and analyzed the tumor location, furthermore, the relationship of neurofibromatosis and schwannoma and neurofibroma on vagal nerve tumor.

Fine-needle aspiration of epithelioid malignant peripheral nerve sheath tumor (epithelioid malignant schwannoma)

The epithelioid variant of malignant peripheral nerve sheath tumor (MPNST), also known as malignant epithelioid schwannoma, is a relatively rare and recently characterized clinicopathologic entity. The epithelioid variant of MPNST shares many clinical features with conventional MPNST but is characterized by different histologic and cytologic features. These include a distinctive nesting pattern and an abundance of cytoplasm not seen in histology of conventional nerve sheath tumors. Cytologically, the epitheliod variant shows a propensity to cellular discohesiveness and a plasmacytoid or epitheliod appearance that is in contradistinction to the spindled appearance of the usual MPNST. Herein, we report our experience with fine-needle aspiration (FNA) of two epithelioid malignant schwannomas and discuss the FNA cytologic differential diagnosis.

Peripheral nerve sheath differentiation in malignant soft tissue tumours: an ultrastructural and immunohistochemical study

Thirteen soft tissue sarcomas with ultrastructural evidence of nerve sheath differentiation were investigated by immunohistochemistry. Three arose in a major nerve or nerve trunk and four patients had von Recklinghausen's neurofibromatosis. Ultrastructurally, 10 cases showed variable differentiation towards Schwann cells, two resembled perineurial cells and one tumour had features suggestive of both cell types. Immunostaining for S-100 protein was positive in eight Schwann cell tumours, negative in the other two Schwann cell tumours and negative in those with perineurial-like cells. No cases demonstrated epithelial membrane antigen, so that the existence of perineurial cells in malignant nerve sheath tumours remains immunohistochemically unsubstantiated; it may be that the perineurial-like cells are merely incompletely differentiated Schwann cells, with nerve sheath differentiation manifesting a continuous spectrum. Leu 7 was detected in four Schwann cell tumours, three of which were ultrastructurally well differentiated. Cytokeratin and desmin were demonstrated only in an undifferentiated pleomorphic area of one Schwann cell tumour. Electronmicroscopy can aid diagnosis by revealing nerve sheath differentiation in malignant soft tissue tumours without demonstrable S-100 protein.