Malignant Nerve Sheath Tumor of the Right Cerebral Peduncle: Case Report

Intracranial Malignant Peripheral Nerve Sheath Tumors Not Associated with a Cranial Nerve: Systematic Review and Illustrative Case

OBJECTIVE

Primary intracranial malignant peripheral nerve sheath tumors (MPNSTs) not associated with cranial nerves are rare and aggressive neoplasms. The rarity of presentation has precluded rigorous analysis of diagnosis, risk factors, treatment, and survival. We analyzed every reported case through exhaustive literature review. In addition, we present our own experience managed with resection, radiotherapy, and first use of targeted therapy in a tumor of this type for a BRAF mutation identified during next-generation sequencing.

METHODS

Two databases, PubMed and Embase, and crossed references were queried for intracranial MPNSTs not associated with a cranial nerve. Extracted variables included demographics, risk factors, tumor characteristics, interventions, and outcomes. Univariate and multivariate analysis was performed to identify factors with survival benefit.

RESULTS

A total of 56 patients (including the present case) were included from 743 literature results. There was a male/female ratio of 1.5:1 and mean diagnosis age of 29.7 ± 21.8 years. Seventy-one percent of cases were sporadic and 23% neurofibromatosis type 1 related. Median survival was 29 ± 22.1 months with 1-year survival of 60%. Factors associated on univariate analysis with reduced survival were subtotal resection (P = 0.05), older age (P = 0.023), triton histology (P < 0.001), and early recurrence (≤6 months) (P = 0.018). On multivariate analysis, gross total resection reduced mortality risk (P = 0.011), whereas triton histology (P = 0.017) and infratentorial tumor location (P = 0.037) increased mortality.

CONCLUSIONS

We present a systematic review of intracranial MPNSTs not associated with a cranial nerve. These tumors have poor prognosis and benefit from aggressive resection, multimodal treatment, and close follow-up. Next-generation sequencing can show molecular alterations for potential targeted therapy.

First documented case of intracranial falcine malignant peripheral nerve sheath tumor: illustrative case

BACKGROUND

The authors reported the first documented case of intracranial extraaxial nonneurofibromatosis type 1-related nontriton malignant peripheral nerve sheath tumor (MPNST) originating from the falx cerebri.

OBSERVATIONS

A 34-year-old man with headache, short-term memory deficit, postural instability, and blurred vision presented with a large heterogenous contrast-enhanced intraventricular cystic lesion originating from the free margin of the falx cerebri. The patient received surgery using the right posterior interhemispheric approach. Gross total resection was performed, and the inferior border of the falx cerebri was resected. The postoperative course was uneventful. Histological examination revealed hypercellular foci of neoplastic spindle cells with hyperchromatic and wavy nuclei. Hence, a diagnosis of MPNST was made based on concomitant immunochemistry findings, including mouse double minute 2 homolog focal positivity and geographic loss of H3K27me3. The patient received adjuvant radiotherapy, and recurrence was not observed.

LESSONS

Intracranial MPNSTs are extremely rare tumors, typically originating from the cranial nerves in the posterior cranial fossa. An even rarer variant of these tumors, referred to as malignant intracerebral nerve sheath tumors, may directly arise from the brain parenchyma. The authors reported the first case of an intracranial MPNST originating from the dura mater of the falx cerebri, acting as an extraaxial lesion with prevalent expansion in the right ventricle.

When "Peripheral" Becomes "Central": Primary and Secondary Malignant Intracerebral Nerve Sheath Tumor: A Case Report and a Systematic Review

BACKGROUND

The intracerebral occurrence of malignant peripheral nerve sheath tumors (MPNSTs) is exceedingly rare, and despite aggressive treatments, local recurrence and poor prognosis are very frequent. Like other brain tumors, these tumors could be primary or secondary, making the term "peripheral" an imprecise term for a primary brain tumor.

OBJECTIVE

To analyze the reported cases of primary and secondary cerebral MPSNTs in terms of diagnosis, treatment, and overall survival. Additionally, we present a case of malignant intracerebral nerve sheath tumor (MINST) treated with radical surgery and radiotherapy.

METHODS

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, one database (PubMed) and crossed references were queried for MPNST with brain metastasis and primary MINSTs from 1971 to 2020. Data regarding demographic features, primary tumor site, risk factors, brain location of the lesion, treatment applied, and overall survival were extracted.

RESULTS

A total of 55 patients were selected (including the reported case): 29 patients were secondary brain MPNST and 26 patients were primary MINST. The mean age was 41.8 ± 22 and 31.2 ± 23 yr, respectively. All brain metastases of MPNST (100%) had a primary tumor elsewhere in the body at the time of diagnosis. The overall survival was significantly shorter in patients with a secondary brain MPNST compared to MINST (P = .002).

CONCLUSION

We present a comprehensive analysis of every reported primary and secondary intracerebral MPNST. The prognosis in terms of survival is worst in the last one despite aggressive treatment. The lack of a primary MPNST in screening tests is sufficient to confirm a MINST at time of diagnosis.

Malignant intracerebral nerve sheath tumor in a patient with Noonan syndrome: illustrative case

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) within the neuroaxis are rare, usually arising from peripheral and cranial nerves. Even more scarce are cranial subclassifications of MPNSTs termed “malignant intracerebral nerve sheath tumors” (MINSTs). These tumors are aggressive, with a strong tendency for metastasis. With this presentation, alongside resistance to adjunctive therapy, complete excision is the mainstay of treatment, although it is often insufficient, resulting in a high rate of mortality.

OBSERVATIONS

The authors report the case of an adult patient with a history of Noonan syndrome (NS) presenting with slowly progressive right-sided hemiparesis and right-sided focal motor seizures. Despite initial imaging and histology suggesting a left frontal lobe high-grade intrinsic tumor typical of a glioblastoma, subsequent molecular analysis confirmed a diagnosis of MINST. The patient’s neurological condition improved after gross-total resection and adjuvant chemo-radiation; he remains on follow-up.

LESSONS

MINSTs are rare neoplasms with a poor prognosis; management options are limited, with surgery being the cornerstone of treatment. Reports on rare tumors such as this will increase awareness of this particular pathology and disclose clinical experience. In this case, the authors were unable to establish a definite cause-and-effect relation between NS and MINST. Nevertheless, it remains the first reported case in the literature.

Retrospective Multicentric Study on Non-Optic CNS Tumors in Children and Adolescents with Neurofibromatosis Type 1

s: The natural history of non-optic central nervous system (CNS) tumors in neurofibromatosis type 1 (NF1) is largely unknown. Here, we describe prevalence, clinical presentation, treatment, and outcome of 49 non-optic CNS tumors observed in 35 pediatric patients (0-18 years). Patient- and tumor-related data were recorded. Overall survival (OS) and progression-free survival (PFS) were evaluated. Eighteen patients (51%) harbored an optic pathway glioma (OPG) and eight (23%) had multiple non-optic CNS lesions. The majority of lesions (37/49) were managed with a wait-and-see strategy, with one regression and five reductions observed. Twenty-one lesions (42.9%) required surgical treatment. Five-year OS was 85.3%. Twenty-four patients progressed with a 5-year PFS of 41.4%. Patients with multiple low-grade gliomas progressed earlier and had a lower 5-year PFS than those with one lesion only (14.3% vs. 57.9%), irrespective of OPG co-presence. Non-optic CNS tumors are common in young patients with NF1. Neither age and symptoms at diagnosis nor tumor location influenced time to progression in our series. Patients with multiple lesions tended to have a lower age at onset and to progress earlier, but with a good OS.

CT, MRI, and 18F-FDG PET/CT findings of malignant peripheral nerve sheath tumor of the head and neck

Background Malignant peripheral nerve sheath tumor (MPNST) is a highly malignant tumor and rarely occurs in the head and neck. Purpose To describe the imaging features of MPNST of the head and neck. Material and Methods We retrospectively analyzed computed tomography (CT; n = 14), magnetic resonance imaging (MRI; n = 16), and ¹⁸F-FDG PET/CT (n = 5) imaging features of 18 MPNSTs of the head and neck in 17 patients. Special attention was paid to determine the nerve of origin from which the tumor might have arisen. Results All lesions were well-defined (n = 3) or ill-defined (n = 15) masses (mean, 6.1 cm). Lesions were at various locations but most commonly the neck (n = 8), followed by the intracranial cavity (n = 3), paranasal sinus (n = 2), and orbit (n = 2). The nerve of origin was inferred for 11 lesions: seven in the neck, two in the orbit, one in the cerebellopontine angle, and one on the parietal scalp. Attenuation, signal intensity, and enhancement pattern of the lesions on CT and MRI were non-specific. Necrosis/hemorrhage/cystic change within the lesion was considered to be present on images in 13 and bone change in nine. On ¹⁸F-FDG PET/CT images, all five lesions demonstrated various hypermetabolic foci with maximum standard uptake value (SUV_max) from 3.2 to 14.6 (mean, 7.16 ± 4.57). Conclusion MPNSTs can arise from various locations in the head and neck. Though non-specific, a mass with an ill-defined margin along the presumed course of the cranial nerves may aid the diagnosis of MPSNT in the head and neck.

Intracranial periventricular supratentorial intraparenchymal schwannoma

Background:

Intraparenchymal schwannomas in the central nervous system are very rare. Because most of these are benign, complete excision is the treatment of choice. Further, their radiological findings are difficult to differentiate from glioma. Because Schwann cells are not indigenous to cerebral parenchyma, a lot of speculation has been attached to their origin.

Case Description:

We report one such rare case of a 17-year-old male who presented to us with a history of headache and vomiting. Neuroradiological findings were suggestive of left temporoparietal solid cystic lesion with enhancement of solid component, suggestive of high grade glioma.

Conclusion:

Intraoperative impression was that of a low-grade glioma but histopathological features were represented as schwannoma.

A long-term survival case of a primary malignant intracerebral nerve sheath tumor

We report a long-term survival case of a primary malignant intracerebral nerve sheath tumor (MINST) occurring in the right frontal lobe of a 13-year old boy. After the gross total resection (GTR), we have performed radiation therapy but it recurred 50 months after the surgery, so the second GTR was performed. Later, second tumor recurrence was found 4 months after the second surgery. Subsequently the third GTR, radiotherapy, and chemotherapy were carried out. At present, the patient has been remaining alive for 77 months without evidence of tumor recurrence. According to the previous reports, the primary MINST is very rare : there are only 8 cases reported. It is also a fast-growing, invasive tumor with poor outcome. This is the first case that had no recurrence for 50 months after the surgery among the reported cases that had been followed up for more than 5 years. It is supposed that a period of recurrence free survival after GTR and low mitotic activity are associated with the patient's prognosis. A GTR followed by adjuvant radiation therapy and chemotherapy will be recommended to patients of MINST.

Malignant intracerebral nerve sheath tumors: a case report with review of the literature

The occurrence of benign nerve sheath tumors within the neuroaxis is uncommon. Even rarer is the finding within brain parenchyma, termed malignant intracerebral nerve sheath tumors (MINST). We present a case of MINST which occurred in the frontal lobe of an 18-year-old male that recurred almost 4 years later. Imaging demonstrated a 4.0 cm lesion with an associated mass effect. He underwent a right fronto-parietal craniotomy for gross total resection. Pathology was inconclusive with a Glioblastoma Multiforme (GBM) as the most likely diagnosis, though gliosarcoma and MINST were also highly considered. Postoperatively, he was treated with chemotherapy and radiation and followed for almost 4 years, when an MRI indicated a recurrence. Resection of the recurrence was highly suggestive of MINST. Surgery was followed by radiation and chemotherapy, but, less than 7 months later, he was readmitted for a surgical-site infection, and, after multiple surgeries, and his family terminated care. Recognizing this unusual tumor in the differential diagnosis of a heterogeneously enhancing intracerebral mass can help surgeons diagnose and treat it. This report also exhaustively reviews the literature and presents diagnostic and treatment strategies.

Malignant peripheral nerve sheath tumors of the trigeminal nerve: a systematic review of 36 cases

OBJECT

Malignant peripheral nerve sheath tumors (MPNSTs) are a rare form of malignancy arising from the Schwann cells of peripheral nerves. MPNSTs of the trigeminal nerve are exceptionally rare, with only a handful of reports in the literature. These tumors are typically very aggressive, resulting in significant patient morbidity and a generally grim prognosis. Most current reports suggest that radical resection with radiation therapy offers the best benefit. In this study, the authors systematically reviewed the world English-language literature on MPNSTs of the trigeminal nerve to analyze the presentations, treatment options, and outcomes for patients with this disease.

METHODS

A literature search for MPNSTs of the trigeminal nerve confined to nonanimal, English-language articles was conducted utilizing the PubMed database, with additional cases chosen from the references of selected articles. Only cases of confirmed MPNSTs of the trigeminal nerve or its peripheral branches, based upon surgical, pathological, or radiological analysis, were included.

RESULTS

From the literature search, 29 articles discussing 35 cases of MPNSTs of the trigeminal nerve were chosen. With the addition of 1 case from their own institution, the authors analyzed 36 cases of trigeminal MPNSTs. The average age of onset was 44.6 years. These tumors were more commonly seen in male patients (77.1%). The gasserian ganglion was involved in 36.1% of the cases. Of the cases in which the nerve distribution was specified (n = 25), the mandibular branch was most commonly involved (72.0%), followed by the maxillary branch (60.0%) and the ophthalmic branch (32.0%), with 44.0% of patients exhibiting involvement of 2 or more branches. Altered facial sensation and facial pain were the 2 most commonly reported symptoms, found in 63.9% and 52.8% of patients, respectively. Mastication difficulty and diplopia were seen in 22.2% of patients, facial weakness was seen in 19.4%, and hearing loss was present in 16.7%. With regard to the primary treatment strategy, 80.6% underwent resection, 16.7% underwent radiation therapy, and 2.9% received chemotherapy alone. Patients treated with complete resection followed by postoperative radiation therapy had the most favorable outcomes, with no patients showing evidence of disease recurrence with a mean follow-up of 34.6 months. Patients treated with incomplete resection followed by postoperative radiation therapy had more favorable outcomes than patients treated with incomplete resection without radiation therapy or radiation therapy alone.

CONCLUSIONS

Trigeminal MPNSTs most commonly present as altered facial sensation or facial pain, although they exhibit a number of other clinical manifestations, including the involvement of other cranial nerves. While a variety of treatment options exist, due to their highly infiltrative nature, aggressive resection followed by radiation therapy appears to offer the greatest chance of recurrence-free survival.

Intracerebral schwannomas: a rare disease with varying natural history

Although intracerebral schwannomas are typically regarded as benign intracranial tumors, malignancy and recurrence have been reported among patients harboring such neoplasms. The available literature consists of case reports and small series that present variable characteristics distinguishing these unusual lesions. Little advancement has been made to further the understanding and management of these tumors. The authors present 3 cases from their institution that highlight the difference between typical benign intracerebral schwannomas and histopathological variants that may portend more aggressive behavior. Also provided is a review of the literature in the hope of gaining a better understanding of these rare tumors.

Periventricular intraparenchymal schwannoma. Case report

A 60-year-old male presented with a rare case of periventricular schwannoma. Imaging studies revealed a partially calcified, well-enhanced tumor in the periventricular area of the left frontal horn. The preoperative diagnosis was low grade glioma, but postoperative pathological findings revealed that the tumor was schwannoma. Most intraparenchymal schwannomas are benign, so total extirpation is usually curative. However, this uncommon neoplasm is difficult to distinguish from mimics, especially low grade gliomas, with only preoperative radiological findings or intraoperative pathological findings. Based on our experience and analysis of the characteristic radiological and pathological features in previous cases, we suggest that an accurate intraoperative diagnosis is possible. The key element is the combination of correct interpretation of the intraoperative pathology analysis and careful evaluation of the preoperative radiological studies. An appropriate intraoperative judgment is important, because the treatment, including the surgical management, would be totally different for schwannoma and glioma.

Imaging diagnosis-malignant peripheral nerve sheath tumor presenting as an intra-axial brain mass in a young dog

A 3-year-old Labrador retriever was presented with acute onset seizures. Magnetic resonance imaging demonstrated an intra-axial mass affecting the right temporal lobe of the brain. Surgical resection and histopathological findings were most consistent with a malignant peripheral nerve sheath tumor. After initial recovery, deterioration 3 months post surgery prompted euthanasia. Post-mortem revealed a mass protruding from the ventral surface of the temporal lobe, encroaching upon the optic chiasm and invading the brain. Histopathology findings were again consistent with malignant peripheral nerve sheath tumor. Although rare, this tumor should be included as a possible differential diagnosis for intra-axial brain masses in dogs.

Malignant peripheral nerve sheath tumor of the abducens nerve and a review of the literature

BACKGROUND

Malignant peripheral nerve sheath tumors are rare, and intracranial occurrences are even more rare. Treatment strategies have varied widely. This article reports the first case of a malignant peripheral nerve sheath tumor of the abducens nerve and provides a literature review that includes 61 cases of intracranial malignant peripheral nerve sheath tumors. Data were analyzed based on age, sex, treatment, survival, immunohistochemical staining, location, tumor grade, and neurofibromatosis association. These tumors more often affect male persons, and the patients affected have a mean age of 39 years. Most patients underwent subtotal or gross total resection and radiation. Intracranial location varied, but most tumors occurred in the cerebellopontine angle. The literature shows that intracranial malignant peripheral nerve sheath tumors are a heterogeneous group. Their association with neurofibromatosis is less clear than that of their extracranial counterparts. Prognosis is poor, but surgical resection and radiation can enhance chances for longer survival. Our aim was to elucidate information about these tumors.

CASE DESCRIPTION

A 30-year-old woman presented with a 6-month history of headaches and diplopia.

RESULTS

Neurological examination revealed no focal deficit. Imaging revealed a heterogeneously enhancing retroclival mass without bony destruction. The tumor originated from the ipsilateral abducens nerve and extended into the Dorello canal; it adhered to the brainstem and cranial nerves. Pathology was consistent with low-grade malignant peripheral nerve sheath tumor.

CONCLUSIONS

At 3-month follow-up, the patient walked with a cane with no further deficits except mild ataxia, which resolved within 6 months. Magnetic resonance imaging revealed a small residual tumor adherent to the basilar artery. At 1-year follow-up and after ocular surgery to correct lateral rectus palsy, the patient was neurologically intact.

Intracerebral malignant peripheral nerve sheath tumor in a child with neurofibromatosis Type 1 and middle cerebral artery aneurysm treated with endovascular coil embolization

Among the neoplastic conditions that affect patients with neurofibromatosis Type 1 (NF1) are malignant peripheral nerve sheath tumors (MPNSTs), which typically arise from peripheral nerves of the limbs, trunk, and lumbar and brachial plexuses. Ionizing radiation is an established risk factor for MPNST development, especially in susceptible patients such as those with NF1. Patients with NF1 are also at risk for intracranial aneurysms, which are increasingly being successfully managed with endovascular therapies. The authors describe the case of a 9-year-old, previously healthy girl who presented in extremis with a right frontal intracerebral hemorrhage resulting from a ruptured right middle cerebral artery (MCA) trifurcation aneurysm. Following urgent decompressive craniectomy, the patient underwent endovascular coil embolization of the MCA aneurysm without complication. Given her mother's history of NF1, the child underwent genetic testing, which disclosed signs positive for NF1. The patient recovered well, but follow-up MR imaging and MR angiography performed at 14 months demonstrated a large frontotemporal mass encasing the right MCA trifurcation. The patient underwent frontotemporal craniotomy and subtotal resection of the mass, which was histologically found to be an intracranial MPNST. The patient received chemotherapy and focal radiation therapy and remains alive at 6 months postresection. To the authors' knowledge, this represents the only known case of intracranial neoplasm arising in the region of an intracranial aneurysm repaired by endovascular coil embolization. While patients with NF1 represent a population with genetic susceptibility to radiation-induced tumors, the pathogenesis of intracerebral MPNSTs remains poorly understood.

Malignant Peripheral Nerve Sheath Tumor of the Vestibulocochlear Nerve and Brainstem

BACKGROUND AND IMPORTANCE

Malignant peripheral nerve sheath tumors are the most common malignant mesenchymal tumors of soft tissues, but they are very rare when found to arise from a cranial nerve and when not in association with neurofibromatosis. These tumors are highly malignant and carry a poor prognosis with survival usually less than 6 months.

CLINICAL PRESENTATION

The authors report the case of a 23-year-old female with no history of phakomatoses, previous irradiation, or known genetic disorders, who presented with a malignant peripheral nerve sheath tumor of the vestibulocochlear nerve and brainstem. Multiple staged skull base approaches were carried out with maximal possible resection. Adjunctive therapies including standard radiation therapy, intensity-modulated radiation therapy, and stereotactic gamma knife radiosurgery were used with an ultimate patient survival of 27 months.

CONCLUSION

To our knowledge, this is the first report describing a patient with a malignant peripheral nerve sheath tumor of the vestibulocochlear nerve and brainstem treated with staged surgical approaches in conjunction with multiple forms of radiotherapy and having a significant survival of more than 2 years.

Recurring Intracranial Malignant Peripheral Nerve Sheath Tumor: Case Report and Systematic Review of the Literature

BACKGROUND AND IMPORTANCE:

To report the clinical presentation and management of an intracranial frontoparietal malignant peripheral nerve sheath tumor (MPNST) and its recurrence in a 6-year-old girl, along with a systematic review of the literature.

CLINICAL PRESENTATION:

A previously healthy 6-year-old girl presented with severe signs of increased intracranial pressure. Magnetic resonance imaging (MRI) revealed a large heterogeneously enhancing mass at the right frontoparietal convexity. The tumor was completely removed, the histological diagnosis was MPNST, and the patient underwent adjuvant radio- and chemotherapy. Fifteen months later, MRI revealed a small local recurrence. After upfront chemotherapy, the recurrence was removed in a radical, ie, true oncological, neuronavigationally guided, en bloc resection, including approximately 1 cm surrounding gray and white matter and overlying dura mater. Neuropathological examination revealed tumor-free margins. The patient again received adjuvant chemotherapy. Four years after diagnosis and 20 months after cessation of adjuvant therapy, there are no signs of tumor recurrence. The literature search resulted in 17 cases of intracranial MPNSTs not associated with cranial nerves. Despite macroscopically complete resection in many cases and adjuvant radio- and chemotherapy, overall survival was poor, with only 5 patients still alive upon publication (including the current patient).

CONCLUSION:

Intracranial MPNSTs not associated with cranial nerves are extremely rare and highly malignant tumors with poor overall survival, probably because of infiltrating growth into surrounding brain tissue. We therefore advocate consideration of nonconventional true oncological en bloc resection when approaching this rare tumor or its recurrence.

Malignant intracerebral giant nerve sheath tumor in a 14-month-old girl with neurofibromatosis type 1: a case report

INTRODUCTION

Malignant intracerebral nerve sheath tumor (MINST) is extremely rare and the origin is still unclear. The authors present the clinical, radiological, and pathological features of a malignant intracerebral giant nerve sheath tumor.

CASE REPORT

A giant tumor in the right frontotemporoparietal lobes causing a midline shift was detected in a 14-month-old girl who presented with developmental delay, vomiting, and lethargy. The physical examination was consistent with neurofibromatosis type 1 (NF-1). Subtotal resection was performed and the histopathological examination revealed the diagnosis of MINST.

DISCUSSION

There are only six cases of malignant intracerebral nerve sheath tumor in the literature. The presented case is the youngest and the occurrence of MINST in a 14-month-old girl may support the hypothesis of multipotent mesenchymal stem cell origin; however, the tumors which arise from multipotent mesenchymal stem cells may be seen in later stages of life. Another important feature of the presented case is the occurrence of MINST in NF-1.

CONCLUSION

MINSTs are extremely rare tumors with unknown origin. The location, the degree, and the size of the tumor and the general condition of the patient are prognostic factors in MINSTs, like in other malignant tumors.

Diagnosis and management of intracranial malignant peripheral nerve sheath tumors

OBJECTIVE

Intracranial malignant peripheral nerve sheath tumors (MPNSTs) are rare and generally carry a poor prognosis. We have analyzed our experience with MPNSTs and conducted a review of the literature in an attempt to identify a rational approach to the management of these tumors.

METHODS

Eight patients underwent surgical treatment for intracranial MPNSTs during a 10-year period from 1996 to 2005. The general strategy was to perform complete resection whenever possible and to provide adjuvant radiotherapy for residual tumor. Chemotherapy was not used in this group. The clinical, radiological, operative, and pathological findings of the patients were reviewed retrospectively.

RESULTS

Six of the eight patients underwent primary operations; two of the eight patients had previously undergone other transcranial surgery operations. Total tumor resection was achieved in five patients. At this time, two have been recurrence-free for 3.5 and 5 years, respectively, and the other three patients had a mean postoperative survival of 7 months. There was one case of near total (>90%) and two cases of partial (<90%) tumor removal; the postoperative survival rate was 4, 4, and 2 months, respectively. Only two patients in our group accepted radiotherapy after surgery; one survived only 4 months and the other has been recurrence-free for 5 years.

CONCLUSION

MPNSTs are fast-growing, invasive tumors with rather unsatisfactory outcomes. Total surgical resection seems to be the most effective therapeutic method, and radiotherapy may play a role in local control.

A true malignant schwannoma of the eighth cranial nerve: case report

OBJECTIVE

The clinical presentation, pathology, treatment, and outcome of a 43-year-old woman with a malignant peripheral nerve sheath tumor arising from a benign schwannoma of the eighth cranial nerve are presented.

CLINICAL PRESENTATION

Initially, the tumor was debulked. After finding malignant areas within the benign tumor, it was considered to be a malignant transformation of a previously benign tumor.

INTERVENTION

Aggressive total resection was obtained during a second-stage procedure. Postoperatively, the tumor bed was radiated for palliation.

CONCLUSION

Despite surgery, radiation, and chemotherapy, the patient died rapidly as a result of disseminated metastatic disease.

Sporadic malignant nerve sheath tumour of the oculomotor nerve

Malignant peripheral nerve sheath tumours (MPNST) are exceedingly rare in an intracranial location. In this report clinical and pathological evidence for the diagnosis of a MPNST arising from of the oclumotor nerve is presented. To our knowledge this is the first such case reported in the medical literature.

Schwannoma with tentorial attachment in the cerebellopontine angle mimicking a meningioma

Intracranial schwannoma not associated with the cranial nerves is rare. It is also an intriguing neoplasm since the Schwann cell is not native to the central nervous system. To date only four cases of intracranial schwannoma arising from the tentorium have been reported. We present a 49-year-old woman who harboured a schwannoma with a tentorial attachment in the right cerebellopontine angle and describe the relevant clinical, radiological and pathological findings. In addition, we briefly review the main hypotheses for the origin of this neoplasm and highlight its resemblance to meningioma and inclusion as a differential diagnosis.