Malignant neurilemomas of peripheral nerves

Malignant peripheral nerve sheath tumor with extensive osteosarcomatous and chondrosarcomatous differentiation: A case report

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MPNST is an aggressive tumor especially in younger age group and even if there is no association with NF1 gene.

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Distant metastasis may appear within 1 year of radical R0 resection of the primary tumor.

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Exhibition of divergent differentiation may be associated with poor prognosis.

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Metastatic MPNST may not exhibit divergent differentiation similar to that exhibited by the primary tumor. This interesting finding warrants further research and analysis to establish its impact on the prognosis.

Background

Malignant peripheral nerve sheath tumor is an uncommon tumor of the peripheral nerves. The commonest presenting symptom is soft tissue mass and pain with local neurological findings. Imaging modalities are unhelpful in making a reliable diagnosis. Treatment is radical resection with adequate clear resection margins. Radiotherapy improves the local control, but the prognosis remains poor especially in those with divergent differentiation.

Summary

A 23-year-old man with no history of neurofibromatosis presented with a swelling on the back which has been gradually increasing in size and causing him discomfort. The tumor was surgically excised and the histopathological examination revealed malignant peripheral nerve sheath tumor with extensive osseous and cartilaginous differentiation. He developed pulmonary metastases one year after the surgical resection. Pulmonary metastatectomy was therefore performed and the histopathology of the metastatectomy specimen revealed metastatic malignant peripheral nerve sheath tumor, but without any osseous or cartilaginous differentiation. He remained well with no recurrence or metastases at 9-month follow-up.

Conclusion

Malignant peripheral nerve sheath tumor is a malignant tumor that behaves aggressively despite adequate radical resection. This case also illustrates extensive osseous and cartilaginous divergent differentiation of the primary tumor which was surprisingly absent in the metastatic lesions. This finding warrants further research.

Diagnosis and management of schwannomas originating from the cervical vagus nerve

INTRODUCTION

A schwannoma is a benign, slow growing, encapsulated nerve sheath tumour. Presentation of a schwannoma is a diagnostic and management challenge.

METHODS

Internet searches of PubMed/MEDLINE(®) for all articles listing schwannomas of the vagus nerve in the cervical/neck region (1980-2012) were undertaken to ascertain diagnostic pitfalls. The references of all articles were cross-checked to include all pertinent contributions. Further articles were traced through reference lists.

RESULTS

Schwannomas are solitary, well circumscribed and medial to the carotid sheath. Preoperative diagnoses of schwannomas in the lateral part of the neck can cause confusion with its nerve of origin (ie whether it arises from the vagus nerve or a sympathetic chain). Computed tomography and magnetic resonance imaging reveal valuable information regarding the location and origin of the tumour as well as aiding surgical planning. The diagnosis can be confirmed intraoperatively. Postoperative recovery of neurological function is dependent on the type of surgery. Histopathological studies searching for classical features and immunohistochemical staining for S100 also confirm the diagnosis.

CONCLUSIONS

Schwannomas should be considered in the differential diagnoses of unusual masses in the neck. Preoperative imaging elicits valuable information regarding the location and origin of schwannomas and histopathology confirms the diagnosis.

Malignant peripheral nerve sheath tumors of the head and neck: management of 10 cases and literature review

BACKGROUND

This study analyzes the management and outcomes of a series of 10 malignant peripheral nerve sheath tumors (MPNST) of the head and neck.

METHODS

From 1984 to 2004, 10 patients underwent surgical treatment of a MPNST. We retrospectively reviewed presenting symptoms, radiological findings, surgical management, and follow-up status and performed a literature review.

RESULTS

Eight tumors were located at the lateral skull base; 2 involved the vagus nerve in isolation. Two lesions were growing within the sinonasal tract. The most common presenting symptom was a rapidly enlarging cervical mass. Seventy percent of the tumors could be resected completely. Long-term follow-up showed a 2-year disease-specific survival rate of 50% and 5-year survival rate of 20%. Negative prognostic indicators were advanced tumor stage, early recurrence, and presumably also the presence of von Recklinghausen's disease. Postoperative adjuvant radiotherapy was found to make no difference in outcome.

CONCLUSIONS

Although rare, MPNST is one of the most aggressive tumors in the head and neck area. Complete tumor removal is the mainstay of treatment and most important prognostic factor of MPNST. Adjuvant radiotherapy should be used to assist surgical excision in local control. The role of adjuvant chemotherapy remains controversial.

Primary brachial plexus tumors: imaging, surgical, and pathological findings in 25 patients

Object

The authors report on the treatment of primary brachial plexus tumors in 25 patients at the University of California, San Francisco. They compare their findings with those obtained in similar series.

Methods

The authors reviewed the electronic and medical records, radiological images, operative reports, and pathological findings in 25 consecutive cases of primary brachial plexus tumors. Cases of metastatic lesions or adjacent neoplasms extending into and involving the brachial plexus were excluded.

At presentation patients ranged in age from 19 to 71 years (mean 47 ±15 years), and neurofibromatosis was present in eight patients (32%). Presenting signs and symptoms included palpable mass (60%), numbness/paresthesias (44%), radiating pain (44%), local pain (16%), and weakness (12%). Duration of symptoms ranged from 2 months to 10 years. Neuroimaging revealed lesions ranging widely in size (volume ~1 to >100 ml). Pathological diagnoses included schwannoma (15 [60%]), neurofibroma (five [20%]), malignant peripheral nerve sheath tumor (four [16%]), and desmoid tumor (one [4%]).

Conclusions

Primary tumors arising in the brachial plexus are rare. Careful workup, surgical technique, and attention to pathological diagnosis optimize management.

Malignant schwannoma of the sciatic nerve originating in a spinal plexiform neurofibroma associated with neurofibromatosis type 1--case report

A 26-year-old man with neurofibromatosis type 1 (NF1) presented with a giant malignant schwannoma of the sciatic nerve. The differential diagnosis of malignant peripheral nerve sheath tumor (MPNST) was based on clinical, radiological, and histological evidence. The tumor apparently originated in a spinal plexiform neurofibroma. The lesion was resected totally without neural damage to the sciatic nerve. However, the tumor recurred within 2 months. The patient died of unknown factors probably associated with the spinal involvement. MPNST associated with NF1 has a poor prognosis due to recurrence or metastasis despite complete macroscopic removal.

Malignant peripheral nerve sheath tumor: analysis of treatment outcome

PURPOSE

To analyze the results of therapy for malignant peripheral nerve sheath tumor (MPNST) and to identify prognostic factors of survival, and of local and distant control of disease.

METHODS AND MATERIALS

From 1975 through 1993, 134 MPNSTs were diagnosed and treated at our institution. Tumor sites included extremities in 36 (27%) cases and non-extremities in 98 (73%). Median follow-up for survivors was 53 months (range: 7-280). There were 14 tumors of histologic grade I disease (10%), 43 of grade II disease (32%), 43 of grade III disease (32%), and 32 of grade IV (24%). Seventy-three patients (54%) underwent radiation therapy (RT) as part of their initial treatment of the primary tumor, including 14 (10%) who had brachytherapy and 16 (12%) who had intraoperative electron irradiation (IOERT) as part of their radiation course.

RESULTS

The 5- and 10-year survival rates were 52% and 34%, respectively. Local and distant failure rates at 5 years were both 49%. On univariate analysis, prognostic factors significantly related to survival (log-rank: p < 0.05) included tumor size, location of disease, history of neurofibromatosis type 1 (NF-1), history of prior irradiation, surgical margin status, use of IOERT or brachytherapy, disease stage, histologic grade and tumor subtype, as well as mitotic rate and the presence or absence of necrosis. On multivariate analysis, only history of prior irradiation (p = 0.023), and surgical margin status (p = 0.0044) remained significant. For local control of disease, univariate analysis showed location of disease, surgical margin status, history of NF-1, history of prior irradiation, mitotic rate, radiation dose > or = 60 Gy, and use of IOERT or brachytherapy to be significant prognostic factors. On multivariate analysis, only surgical margin status (p = 0.0024), RT dose (p = 0.021), and use of IOERT or brachytherapy (p = 0.016) remained significant. For distant control of disease, significant prognostic factors on univariate analysis included tumor size, stage, tumor grade, mitotic rate, presence or absence of necrosis, and histologic subtype. On multivariate analysis, tumor size (p = 0.0065), grade (p = 0.036), and histologic subtype (p = 0.001) remained significant. Patients with perineurial MPNSTs had a much lower rate of distant metastasis and a better overall survival as compared with other histologic subtypes.

CONCLUSION

Management of patients with MPNST involves a multi-modality approach. The goal of surgery is complete resection with negative margins. Adjuvant irradiation to doses > or = 60 Gy and the inclusion of IOERT or brachytherapy are associated with improved local control of disease.

Primary intraosseous malignant peripheral nerve sheath tumor: a case report and review of the literature

Primary intraosseous malignant peripheral nerve sheath tumors (MPNST) are exceptionally rare; the case reported here represents the first documented example occurring in the spinal column. The tumor arose in the second cervical vertebra of a forty year old woman of Asian origin. She had no stigmata of von Recklinghausen's disease (VRD). Plain radiographs and magnetic resonance imaging showed an osteolytic lesion within the expanded body of the vertebra. Histology revealed spindle-shaped tumor cells with nuclei showing pleomorphism, pallisading and mitotic activity. The cells stained positively for S-100 protein. The patient underwent stabilisation of the cervical spine and tumor excision as a two-stage procedure. She died of pulmonary metastases one year later. We have reviewed the literature on the pathology of these tumors.

Neoplasms with neural differentiation: a review. Part II: Malignant neoplasms

Malignant peripheral nerve sheath tumors (MPNSTs) encompass a wide and unusual group of neoplasms with features of neural differentiation. They most commonly present as spindle cell neoplasms and it can be difficult to differentiate them from other spindle cell neoplasms such as leiomyosarcomas, fibrosarcomas and synovial sarcomas. Strict criteria need to be applied in order to make the diagnosis of MPNSTs. Helpful features include contiguity with a nerve or an association with von Recklinghausen disease. The use of immunohistochemical stains may also help to confirm the diagnosis. Markers such as S-100 protein, neurofilament, epithelial membrane antigen and Leu-7 (CD57) are frequently used to assess neural differentiation in these neoplasms. In addition to the spindle cell pattern, MPNSTs may also display an epithelioid pattern. Rarely, other elements may be seen including glands in the so-called glandular MPNST or muscle in triton tumors. In more unusual cases cartilage, adipose tissue and even bone are present. Also included in the group of MPNSTs are the peripheral neuroepithelial tumor, neurotropic or desmoplastic melanomas and malignant granular cell tumors. MPNSTs are highly aggressive tumors and should be treated accordingly.

Primary spinal malignant schwannoma

Malignant schwannomas are uncommon primary tumours of nerve sheath origin. They are rarely found within the spine and spinal canal, and little is known about their management in this unusual location. We describe the presentation of three patients with primary spinal malignant schwannomas and discuss the surgical management.

Malignant schwannoma arising in a paranasal sinus

A case of malignant schwannoma arising in a paranasal sinus is reported. In this case, histological hallmarks were lost because of the poorly differentiated nature of the tumour. Immunohistological techniques were applied to the diagnosis, confirming the neural origin of this tumour. Malignant schwannoma is a relatively rare disease in the nasal cavity and paranasal sinuses. For the treatment of this tumour, wide resection is recommended. In this patient, radical resection of the maxilla with orbital and ethmoid exenteration was performed. The patient recovered uneventfully with no evidence of disease three years after surgery.

Malignant peripheral nerve sheath tumor of the orbit in a 15-month-old child. Nine-year survival after local excision

BACKGROUND

Malignant peripheral nerve sheath tumors are extremely rare orbital tumors that carry a poor prognosis despite wide excision with disfiguring surgery, chemotherapy, or radiotherapy. The authors present the youngest reported case, a 15-month-old boy who underwent an orbitotomy to excise a bilobed tumor from the right orbit.

FINDINGS

Histologic examination revealed a malignant peripheral nerve sheath tumor; standard treatment options, including orbital exenteration, chemotherapy, and radiotherapy, were denied and instead the patient was followed with serial computed tomography scans and magnetic resonance imaging.

RESULTS

Nine years later, the patient remains without evidence of recurrent tumor and visual acuity is 20/20.

CONCLUSION

This patient's course suggests that orbital malignant peripheral nerve sheath tumors, if believed to be completely excised at the time of surgery, might be followed with careful neuroimaging studies for signs of recurrence.

Magnetic resonance appearance of peripheral nerve sheath tumors

Magnetic resonance imaging (MRI) was used to evaluate 22 histologically proven peripheral nerve sheath tumors, approximately two-thirds of which arose in the lower extremity. The histologic distribution was as follows: 12 schwannomas, 7 neurofibromas, and 3 malignant peripheral nerve sheath tumors (2 of which occurred in patients with neurofibromatosis). Most lesions demonstrated an intermediate to moderately bright signal on T1-weighted images and were minimally inhomogeneous. All lesions were moderately bright on proton-density-weighted images and bright on T2-weighted images, again with variable inhomogeneity. The extent of the tumor was best assessed on proton-density- and T2-weighted images. Smooth margins were noted in 19 lesions. Of the 3 remaining lesions, 2 were malignant (but had been subjected to biopsy prior to MRI), and the other lesion was a plexiform neurofibroma. MRI accurately determined the relationship between the lesion and the adjacent neurovascular structures and muscles, thereby assisting surgical management. On MRI, 5 lesions demonstrated coexistent subtle muscle atrophy along the longitudinal axis of surrounding or distally innervated musculature. This latter finding, together with the presence of a tumor in the vicinity of a large nerve trunk, suggests a peripheral nerve sheath neoplasm.

Malignant peripheral nerve sheath tumors of the buttock and lower extremity. A study of 43 cases

Using strict clinical and pathologic criteria for the inclusion of cases, the authors have reviewed the clinicopathologic features of 43 malignant peripheral nerve sheath tumors of the buttock and extremity seen over a 35-year period. Twenty-three (53%) of the patients had neurofibromatosis (VRN), whereas 20 (47%) did not. Fifty-one percent of the patients were women. The mean age at presentation was 36 years for patients with VRN and 44 years for patients without VRN. A nerve of origin was identified for 72% of the cases and an associated neurofibroma for 44% (65% with VRN and 20% without VRN). The mean greatest dimension of the tumors was 12.3 cm, and this did not differ significantly between the two groups. The predominant histologic pattern in 86% of the tumors was that of tightly packed spindle cells in an interlacing and woven pattern; heterologous sarcomatous elements were noticed in 12% of the cases. Surgical resection was the main modality of treatment for all patients; 65% also received adjuvant therapy. Follow-up evaluation was done in every case. An unexpected finding was the absence of a significant difference in survival rates between patients with and without VRN. Overall, 63% of the patients died of tumor: 65% of the patients with VRN and 60% of the patients without VRN. Large tumor size and high mitotic rate (greater than 20 per 10 high-power fields) portended a poor prognosis, as did the need for resection by amputation. Adjuvant radiation therapy and chemotherapy did not affect survival rates.

CT findings in orbital tumours of nerve sheath origin

The clinical and CT features of orbital nerve sheath tumours (13 neurofibromas and 17 neurilemmomas, including one malignant neurilemmoma) have been reviewed. The commonest clinical findings were proptosis, mild impairment of visual acuity and disorders of eye movements. No significant correlation with intra- or extraconal location and these symptoms was found. The two types of tumour were morphologically similar, most being smooth retrobulbar masses, elongated in the long axis of the orbit; lobulation was slightly more common with neurofibromas. The neurilemmomas were generally larger than the neurofibromas. The distribution of neurilemmomas in the retrobulbar space, and in its intra- and extraconal compartments appeared random, but most neurofibromas occurred in the upper orbit and three quarters lay extraconally. The apex of the orbit was seen to be clear of tumour in all intraconal neoplasms (except the one case of malignant neurilemmoma); this observation may be useful in differentiation from intrinsic optic nerve tumours and pseudotumour. Focal or generalised enlargement of the bony orbit was common, being seen in four-fifths of neurilemmomas and three-quarters of neurofibromas. Tumour density was homogeneous for all the neurilemmomas and in the majority of neurofibromas: attenuation coefficients were slightly higher for the neurofibromas. Subcutaneous extension was more common in neurofibromas, occurring in approximately one third of cases but was observed in about a tenth of the neurilemmomas. Enhancement with intravenous contrast medium was variable; contrast medium was helpful in showing intracranial extension. Although the CT findings did not allow unequivocal presurgical diagnosis, they were suggestive in many cases and facilitated biopsy.

Orbital malignant peripheral nerve sheath tumours

We describe three patients with malignant peripheral nerve tumours in the orbit and review the existing literature on these rare lesions.

Malignant schwannoma of the gingiva

A case of malignant schwannoma on the buccal-attached gingiva in the right mandible is described. There was no evidence of multiple neurofibromatosis and the tumor was totally excised. Numerous closely-packed spindle-shaped cells showing marked mitotic activity were seen. The recognizable pattern of neurilemmoma could be observed focally in a small area of the tumor. At two years follow-up, the patient has remained symptom-free with no signs of metastasis.

Malignant schwannoma of facial nerve

The occurrence of malignant schwannoma in children is rare. A search of English language literature did not reveal involvement of cranial nerve among children.

Epithelioid malignant schwannoma. A study of 14 cases

We report a light and electron microscopic, immunohistochemical, clinical and prognostic study of 14 patients with epithelioid malignant schwannoma. In 8 patients the tumour involved a major nerve. The tumours were rather small in most instances, the largest diameter being less than 5 cm in 7 cases. Light microscopically, they showed highly cellular areas of epithelioid, polygonal or rounded cells characteristically forming cords and rows and arranged in nodules of varying size. Spindle cell sarcoma areas as in classical malignant schwannoma were seen in 9 cases, and neurofibromatous areas in one case. Four cases were entirely epithelioid in appearance. Electron microscopically the epithelioid tumour cells showed nuclei with mostly even contours containing one or two trabecular or reticular nucleoli, cytoplasmic projections, intra-cytoplasmic myelin-like figures, intercellular junctions and discontinuous, sometimes multilayered external lamina material. The ultrastructural findings indicate that epithelioid malignant schwannoma is a tumour of neural crest derivation having features of Schwann cell differentiation. Immunohistochemically, S-100 protein was demonstrated in 7 tumours and neuron specific enolase in 3. There was a female predominance, 9/14, and a median age of 38.5 years (range 17-74). The extremities, including the hip and shoulder regions, were the most common sites, 12/14. The tumour proved highly malignant; 9 of 14 patients were dead at the time of follow-up and a high incidence of metastasis (7 of 14) was observed.

Malignant peripheral nerve sheath tumors. A clinicopathologic study of 120 cases

A review was done of 120 cases of malignant peripheral nerve sheath tumor (MPNST) seen during a 71-year period. Of the 120 patients, 52 were males and 68 were females with a mean age at diagnosis of 35.3 years; 12 patients were younger than 20 years. The series included 62 (52%) patients with neurofibromatosis, 13 (11%) with postradiation sarcomas, and 19 (16%) with metaplastic foci. The incidence of MPNST arising in neurofibromatosis was 4.6% in the current series and 0.001% in the general clinic population. Tumors greater than 5 cm and the presence of neurofibromatosis adversely affected the prognosis (P less than 0.05). When both features were present, survival was greatly decreased. Patients with tumor in the extremities did better than those with head or neck lesions. Metaplastic foci or previous radiation at the tumor site did not alter the prognosis. Each tumor was graded 1 to 4 on the basis of cellularity, pleomorphism, mitotic index, and necrosis. No significant correlation was noted between survival and either grade or mitotic rate. Survival was improved when total rather than subtotal resection was done. This was most marked in patients with a small lesion, which may reflect the difficulty in adequately excising large tumors. Adjuvant radiation or chemotherapy did not appear to affect survival. The MPNST is an aggressive uncommon neoplasm, and large tumor size, the presence of neurofibromatosis, and total resection are the most important prognostic indicators.

Malignant peripheral nerve sheath tumors with divergent differentiation

Malignant peripheral nerve sheath tumors are uncommon sarcomas of Schwann cell or fibroblastic derivation which occasionally show histologic evidence of focal divergent differentiation to rhabdomyosarcoma, osteosarcoma, chondrosarcoma, angiosarcoma, epithelial elements, or a combination thereof. The finding of these heterotopic elements in nerve sheath sarcomas is believed to illustrate the differentiating capacity of neuroectodermal tissue. The authors present the clinicopathologic features of 17 such tumors, which represent 14.7% of the malignant peripheral nerve sheath tumors in the authors' institutional experience. Most of the lesions were associated with von Recklinghausen's disease. These tumors do not seem to differ from ordinary malignant peripheral nerve sheath tumors in presentation, operative, gross, and microscopic features, response to therapy, or prognosis.

Malignant peripheral nerve sheath tumors in childhood

Malignant peripheral nerve sheath tumor (MPNST) is an uncommon sarcoma in the pediatric population; however, its presence should be considered in a child with an enlarging or painful soft-tissue mass. Diagnosis of this neoplasm depends on either the demonstration of its origin within a peripheral nerve or the association with a contiguous neurofibroma. We have identified 16 cases of MPNST involving children 16 years of age or less, which represent 12.8% of the total cases seen at the Mayo Clinic. Most of the lesions arose in children with von Recklinghausen's disease and were associated with a contiguous neurofibromatous component. The mean survival of patients who were known to have died of tumor was only 1.8 years. This sarcoma requires prompt aggressive therapy utilizing wide surgical excision. Because of the association of MPNST with von Recklinghausen's neurofibromatosis, a careful workup and family history should be obtained for the potential prognostic value and for the purpose of genetic counseling.

Malignant transformation in a plexiform neurofibroma of the median nerve

A malignant schwannoma of the median nerve occurred in a 27-year-old woman with multiple neurofibromatosis (von Recklinghausen's disease). A growth had been present at the left wrist since birth and was partially excised at the age of 10 years. The patient refused an amputation and radical local excision did not control this highly malignant tumor.

Neurogenic sarcomas in patients with neurofibromatosis (von Recklinghausen's disease). Light, electron microscopy and immunohistochemistry study

Thirteen soft tissue neurogenic sarcomas from twelve patients with neurofibromatosis (Von Recklinghausen's disease) were ultrastructurally examined. Electron microscopic studies revealed a wide spectrum of morphological manifestations varying from schwannian to fibroblastic, histiocytic, fibrohistiocytic and relatively undifferentiated cellular proliferations. A similar variation on light microscopic appearances has been previously reported in these neurogenic sarcomas. Neurogenic sarcomas occurring in patients with neurofibromatosis (Von Recklinghausen's disease), represent a heterogeneous group of neoplasms with various patterns of differentiation identified ultrastructurally. The morphologic expressions of these neurogenic neoplasms can be conceptualized as a disorderly growth of the various peripheral nerve cellular components, or, as has been previously suggested, as a result of the multipotential nature and metaplastic ability of Schwann cells. S-100 protein immunohistochemistry was only positive in those neoplasms ultrastructurally proven to represent schwannian cellular proliferations. This study serves to document the range of fine structure that may be found in neurogenic sarcomas, to correlate the ultrastructural findings with the light microscopic appearance of these tumors, to determine the specificity of the electron microscopic findings, and immunohistochemistry for S-100 protein and assess their possible value in differential diagnosis.

[Neurogenic sarcoma of the head and neck with contact to the skull base (author's transl)]

The neurogenic sarcoma is a neoplasm found seldom. It descends from the sheaths of peripheric nerves. If this tumor develops from a solitary or multiple neurofibroma, it might also be called a neurofibrosarcoma. All other synonyms, especially that of the malignant schwannoma, should better be abandoned for histogenetic reasons. Today the classification of all tumors of the peripheral nervous system is based on a suggestion of the WHO from 1969. The tabular summary of the literature shows that only a little more than a hundred cases of neurogenic sarcoma of the head and neck were reported during the last 50 years. Differential diagnosis of this malignant tumor includes nearly all other malignant neoplasms of soft tissue, sometimes even anaplastic carcinoma. Histopathology, including electron microscopy, is described in general and also in detail with regard to three cases. Three forms of micro-morphological variants are dealt with, too. For diagnosis histological examination will be absolutely successful only in cases of neurofibromatosis or in cases where the nerve from which the tumor originates may be identified. Otherwise, conventional and computerized X-ray tomography may be helpful. Finally, some therapeutic and prognostic principles are discussed.

A transplantable human malignant Schwannoma

A human malignant Schwannoma was serially transplanted through three generations in nude mice. The tumours grew readily and the take-up rate was 100 per cent. No metastasis was observed in nude mice. Morphological features of the original tumour were strictly maintained through all the transplant generations. The tumour cells of the original and of the transplants showed features of primitive Schwann cells of embryonic nerve trunks.

Electron microscopy in the diagnosis of malignant schwannoma

Fifteen malignant schwannomas were examined by light and electron microscopy. Five tumors arose in patients with neurofibromatosis and five were contiguous with a peripheral nerve (Group I). Five tumors met neither of these generally accepted diagnostic criteria but were light microscopically seen as compatible with malignant schwannoma when examined under light microscope (Group II). In the better differentiated areas of Group I lesions, long, overlapping, tightly packed cytoplasmic processes were parallel to homogeneous flocculent material, occasionally assuming a linear appearance suggesting basal lamina. In Group II, similar cytoplasmic processes were present but the extracellular material was less extensive and had a less obvious relationship to the plasma membrane. In neither group were fine intracytoplasmic filaments prominent. Malignant schwann cells are seldom as ultrastructurally differentiated as their benign counterparts. Nevertheless, within the context of well-studied light microscopy and the sampling error inherent in ultrastructural examination, electron microscopy can support the diagnosis of malignant schwannoma.

Neurogenic sarcomas of the neck in neurofibromatosis

Based on two observations and a review of the literature, the pathological and clinical findings in sarcomas of the neck in patients with neurofibromatosis are described. Histologically these neurogenic tumours show a manifold picture; in addition to spindle-cell sarcomas pleomorphic structures are to be found, which can be similar to rhabdomyo-, lipo-, chondro-, angio-, or osteogenic sarcomas so that a histological diagnosis of a neurogenic sarcoma cannot always be made without clinical details. Up to the present surgical treatment is preferred; the value of cytostatic therapy and irradiation is controversial. The results of treating these tumours are unsatisfactory. Of 29 cases reported in the literature, only two could be found in which the patient survived without a recurrence for more than five years.

Malignant schwannoma--clinical characteristics, survival, and response to therapy

One hundred and sixty-five cases of malignant schwannoma were reviewed. Sixty-five (40%) of the patients had evidence of disseminated neurofibromatosis. Patients with neurofibromatosis were younger, had malignant schwannomas that were centrally rather than peripherally located, and had a shorter five-year survival (23%) than patients with solitary malignant schwannomas (47%). Histologically, tumors developing in patients with neurofibromatosis had a collagenous appearance, while tumors in patients without neurofibromatosis were undifferentiated and highly cellular. The clinical course of both groups of patients tended to be that of multiple local recurrences, although local recurrence had a more ominous prognosis in patients with neurofibromatosis. Chemotherapy responses in all these patients were extremely poor; however, the results of adjuvant therapy after surgery appeared encouraging. Fourteen patients (8.5%) had a malignant schwannoma in an area of prior radiation therapy and died of disease a median of 14 months after diagnosis. Malignant schwannoma should be considered in the differential diagnosis of tumors developing in areas previously treated with radiation.

Malignant tumors of nerve sheath origin

A clinicopathologic study of malignant nerve sheath tumors diagnosed between 1962 and 1979 at the Massachusetts General Hospital was undertaken. During this 17-year period, 24 patients with such a neoplasm were seen while 607 patients were treated for schwannoma or neurofibroma. Criteria were developed for establishing the nerve sheath origin and malignancy of a given neoplasm which allowed a secure diagnosis of malignant nerve sheath tumor to be made in 11 of the 24 cases. In 7 of the remaining cases, the malignant tumors were of uncertain histogenesis and in 6 cases, a new diagnosis was made. The malignant tumors constituted 2% of all neoplasms of the nerve sheath origin diagnosed during this period. An attempt was made to grade these neoplasms, but clinical and histologic parameters were only approximately predictive of their behavior. The treatment and survival or the 11 patients with malignant nerve sheath tumors and the 7 with malignant neoplasms of uncertain histogenesis are detailed and compared. In the former group, 4 patients died within four and a half years and there were eight recurrences in 4 patients. In the latter group, 4 died within three and a half years and there were five recurrences in 3 patients.

[Nerve sheath tumors: malignant schwannoma (author's transl)]

The morphology and biology of tumors of the nerve sheath show rather heterogeneous aspects. In most the site of origin seems to be the Schwann's cells. Essentially these tumors can be differentiated into three groups: 1. malignant schwannoma, 2. neurinoma, and 3. neurofibroma. Although the Schwann's cell is the common origin, the three different tumors can be well differentiated histologically with the exception of malignant schwannoma and spindle cell sarcoma. The clinical symptoms are determined by the location of the tumor and are without general characteristics. The treatment of choice is always radical surgery. In addition, radiation and chemotherapy are indicated in special cases.

Primary malignant peripheral nerve tumors (malignant schwannomas). A clinicopathologic and electron microscopic study

A clinicopath-logic and electron microscopic study was performed on 35 cases of primary malignant peripheral nerve tumors, among which 12 developed in association with neurofibromatosis (von Recklinghausen's disease) and further 11 in keeping with anatomically discernible nerves in patients without neurofibromatosis. Depending upon the histologically predominant pattern, these tumors were subdivided into three groups: 23 compact spindle cell, 6 myxoid, and 6 epithelioid varieties of the tumor. The common ultrastructures in three of the 35 tumors were as follows: 1) The cell membranes manifested characteristic infoldings and lamellar configuation. 2) The tumor cell surfaces were coated by occasional basal lamina or homogeneously electron-dense membranous material. 3) The cytoplasms contained well-developed organelles and a few neurosecretory-type granules. Differential points from other soft-tissue sarcomas were briefly discussed on the histologic basis.

Solitary neurogenous sarcomas of the head and neck

The clinical histories of three patients with neurogenous sarcomas involving the head and neck are detailed. The most satisfactory treatment suggested for such tumors involves combined therapy with chemotherapy, radiation, and radical surgical excision. By so doing, potential patient cure might be further increased and survival rates further improved.

Central neurilemmoma of the jaws. Review of literature and case report

Neurilemmomas presenting as primary central bone tumors are extremely rare. Only 21 cases have been reported to have arisen in the jaws; all except for one have occurred in the mandible. The majority of these have been associated with the inferior dental nerve. A case of a central neurilemmoma arising in the anterior mandible is reported. Its probable origin is from one of the alveolar branches of the incisive nerve--an unusual site in the mandible. The radiographic features include expansion of cortical bone, resorption of roots of teeth, the presence of lace-like bony septa and a spotty calcification within the tumor. The treatment and the prognosis are briefly discussed.

Synchronous malignant glandular schwannomas in congenital neurofibromatosis

An eight-year-old child with congenital neurofibromatosis developed rapidly growing synchronous malignant schwannomas in the neck and mediastinum. These tumors, displaying a biphasic pattern of spindle cell sarcoma admixed with mucinous epithelium, represent the eighth and ninth known examples of glandular schwannoma. The clinical and pathological features of this case are detailed and the histogenesis of the tumors discussed.

Ancient neurilemmoma (schwannoma)

A clinical and light microscopic study of 11 patients with ancient neurilemmoma is presented. Ancient neurilemmoma is a cellular form of ordinary neurilemmoma, showing nuclear polymorphism and hyperchromasia. Seven patients were female and 4 were male; their ages ranged between 37 years and 81 years, with a median of 59 years. Seven tumours were 2.5 cm or larger in the widest diameter, and had been slowly enlarging for one year or more. All tumours were solitary, encapsulated showing nuclear polymorphism and hyperchromasia without any mitotic activity. The differential diagnosis is discussed. Follow-up information available on all patients confirmed that the clinical course is benign.

Combination chemotherapy of metastatic malignant schwannoma with vincristine, adriamycin, cyclophosphamide, and imidazole carboxamide: a case report

This report describes a patient with a 15-year history of schwannoma (peripheral nerve sheath sarcoma) who developed extensive pulmonary metastases associated with hypoxemia. Treatment with chemotherapy consisting of cyclophosphamide, vincristine, Adriamycin, and imidazole carboxamide resulted in a complete remission lasting 17+ months. Malignant schwannoma should probably be regarded as a drug sensitive neoplasm.