Other Nerve Sheath Tumors of Brain and Spinal Cord.

The three main types of nerve sheath tumors are schwannomas, neurofibromas and perineuriomas. Multiple neurofibromas throughout the body are the hallmark of Neurofibromatosis type 1 (NF1). Spinal nerve sheath tumors are classified in the group of intradural extramedullary spinal cord tumors, in which they are the most common type (25-30%). Their incidence is 3-4 per 1 million people. Spinal schwannomas are encountered sporadically or in the context of Neurofibromatosis type 2, while neurofibromas are typical for patients with Neurofibromatosis type 1. Neurofibromas are composed predominantly of Schwann cells and fibroblasts, alongside which are also found axons, perineurial cells, mast cells and extracellular matrix. Most of the neurofibromas are asymptomatic. Any increase in the size of a neurofibroma or the presence of pain is an indicator of a possible malignant degeneration. Neurofibromas are treated surgically. Neurofibromas involve the whole nerve and cause its fusiform enlargement which makes it impossible to preserve the nerve's functions if complete tumor removal is performed. Hence, such tumors are initially observed. In case of progressive growth, the options are either resection of the tumor and immediate reconstruction with a peripheral nerve graft (e.g., nerve suralis interposition graft) or subtotal removal and follow-up. Malignant peripheral nerve sheath tumors (MPNST) are very rare tumors with incidence of around 1 per 1,000,000 people. MPNST account for 3-10% of all soft-tissue sarcomas. The most common initial symptom of MPNST is a painless mass. Any rapid increase in a subcutaneous mass or rapid onset of symptoms should raise the suspicion of a malignant tumor. In patients with diagnosed NF1, the recent rapid increase in a known lesion should raise the suspicion of malignant degeneration of the lesion and opt for active treatment. In the case of MPNST a wide surgical excision is advocated. The resectability depends greatly on the location of the tumors and varies from around 20% in paraspinal MPNST and reaches 95% in MPNST localized in the extremities. MPNST are a rare disease and should be managed by a multidisciplinary team of neurosurgeons, radiologists and oncologists.

Patient demographics, tumor characteristics, and outcomes following surgical treatment of benign and malignant brachial plexus tumors: a systematic review.

BACKGROUND: Various treatment options have been introduced for the management of primary tumors of the brachial plexus (BP), ranging from conservative therapy to wide local excision with/without postoperative chemoradiotherapy. However, no consensus exists regarding optimal treatment strategies based on collated and published data. OBJECTIVE: The aim of this study was to investigate the clinicopathological characteristics and outcome of patients with primary tumors of the BP who underwent surgical treatment. DATA SOURCES: A systematic search of the four main online databases, including Web of Science (WOS), PubMed, Scopus, and Google Scholar, was conducted. STUDY SELECTION: All related articles addressing the clinical outcome and role of surgical interventions for management of primary tumors of the BP. INTERVENTION: Optimal surgical and radiotherapeutic interventions for benign and malignant lesions based on the pathologic characteristics and location of primary BP tumors. RESULTS: A total of 687 patients (693 tumors) with a mean age of 41.7±8.7 years old were evaluated. In total, 629 (90.8%) tumors were benign, and 64 (9.2%) were malignant, with a mean tumor size of 5.4±3.1 cm. The location of the tumor was reported for 639 patients. For these tumors, 444 (69.5%) originated from the supraclavicular region, and 195 (30.5%) were infraclavicular. The trunks were the most common location for tumor involvement, followed by the roots, cords, and terminal branches. Gross total resection was achieved in 432 patients and subtotal resection (STR) was performed in 109 patients. With neurofibromas, STR still resulted in good outcomes. The outcomes following treatment of malignant peripheral nerve sheath tumors were poor regardless of the type of resection. In general, symptoms related to pain and sensory issues resolved rapidly postoperatively. However, the resolution of motor deficits was often incomplete. Local tumor recurrence occurred in 15 (2.2%), patients and distant metastasis was observed in only eight (1.2%) cases. The overall mortality was 21 (3.1%) patients among the study population. LIMITATIONS: The main limitation was the lack of level I and II evidence. CONCLUSIONS: The ideal management strategy for primary BP tumors is complete surgical resection. However, in some cases, particularly for neurofibromas, STR may be preferable to preserve maximal neurological function. The degree of surgical excision (total or subtotal) mainly depends on the pathological characteristics and primary location of the tumor.

Update on Peripheral Nerve Sheath Tumors in Upper Extremity: A Descriptive Review.

Peripheral Nerve Sheath Tumors (PNSTs) are extremely uncommon and it is almost certain that no individual upper limb surgeon will gain great experience in a lifetime with these lesions. Benign and malignant PNSTs are separately analyzed in this descriptive review and discussed focusing the attention towards the most important features. A comprehensive and summarized overview of this topic is offered to the reader in order to improve the complex management of these tumors from diagnosis to treatment. A systematic search in PubMed was carried out using the keywords (and synonyms) written below in order to find relevant and most cited papers. Reckoning the rarity of the pathology, few selected case reports were taken into account. A compendium of each PNST was created to sum up the personal experience of the Authors who wrote the articles, critically inspected and analyzed. Every section of the paper is meant to provide useful tips to the reader.

Spinal Malignant Peripheral Nerve Sheath Tumours in Nigerians.

BACKGROUND: Spinal Malignant peripheral nerve sheath tumours (MPNSTs) are very rare aggressive tumours with poor prognosis. Little is known about these tumours in sub-saharan Africa. OBJECTIVES: This study aims to evaluate the clinical profile and outcome of management of these tumours in a resource limited country. METHODS: We retrospectively analysed data from the records of patients who had surgery for spinal MPNSTs at our center between January 2004 and December 2018. RESULTS: There were four patients in this study (M:F= 1:1). The ages ranged from 27-53 years with a mean of 43.25 ± 11.84 years. The tumour was located in the thoracic region in 2 of the patients (50%), the lumbar region in one (25%) and thoracolumbar in the 4th patient. Three patients (75%) presented with back pain while limb weakness, sensory deficit and sphincteric dysfunction were present in all patients at presentation. The duration of symptoms were 2 months in 2 patients (50%) and 3 months in the other 2. None of the patients had neurofibromatosis. Gross total tumour excision was achieved in 2 patients (50%) and subtotal resection in the other 2. The tumours were high grade in three patients (75%) and low grade in one. Two patients had adjuvant radiotherapy. Two of the patients were dead within 6 months of the diagnosis, another one within 18 months while one patient is still alive 3 years after. CONCLUSIONS: MPNSTs are very rare in our practice. Most of the tumours were high grade tumours and ran an aggressive course.

Malignant peripheral nerve sheath tumors - Outcomes and prognostic factors based on the reference center experience.

INTRODUCTION: Malignant peripheral nerve sheath tumor (MPNST) accounts for about 5% of soft tissue sarcomas. It can occur as sporadic diseases or can be associated with type 1 neurofibromatosis. MPNST is usually associated with poor prognosis, mostly due to their aggressive behavior, high metastatic potential, and resistance to chemotherapy. Our study aimed to determine treatment outcomes and associated prognostic factors in a large cohort of patients with MPNSTs treated at the reference sarcoma center. METHODS: 239 consecutive patients (114 women and 125 men) diagnosed with MPNST between March 1998 and March 2018 who were treated with surgery with curative intent in the reference sarcoma center were included in the retrospective analysis. RESULTS: The mean age at diagnosis was 51 years (range 15-86). 28 (11.7%) patients had neurofibromatosis type 1 associated tumors (NF1 positive). Median OS was 126.5 months and 5-year survival rate was 61.9% in the group treated with curative intent. Median DFS, LRFS and DMFS were 91.6, 126.5 and 126.5 months, respectively. We identified tumor size, high tumor grade and positive surgical margins as independent negative predictors of DFS, LRFS, DMFS and OS. CONCLUSIONS: High-quality surgery remains a gold standard of MPNST treatment. High grade, size and quality of surgery are significant independent prognostic factors for overall survival. There is an unmet need for improvement, especially regarding the perioperative treatment and treatment of metastatic disease. Future studies on the biology of MPNST would lead to the development of novel treatment options and improvement of treatment outcomes.

Malignant peripheral nerve sheath tumors: Analysis of the national cancer database.

OBJECTIVES: Malignant peripheral nerve sheath tumor (MPNST) is a rare type of soft tissue sarcoma (STS) that carries significant mortality. Given the rarity of MPNST, current knowledge on the disease is limited. We aim to characterize patient, tumor, and treatment factors, and determine variables associated with 5-year overall survival (OS) in individuals with MPNST. MATERIALS AND METHODS: We utilized the National Cancer Database (NCDB) to identify adult patients diagnosed with MPNST from 2004 to 2015, and analyze patient, tumor, treatment, and survival data. American Joint Committee on Cancer (AJCC 8) staging criteria for STS was utilized. RESULTS: In our cohort of 2,858 patients with MPNST, median age at diagnosis was 47. The 5-year OS rate was 52%. Age, race, tumor size, and treatment regimen significantly predicted 5-year OS on univariate analysis. AJCC 8 stage appeared to predict 5-year OS in head and neck tumors (though not significantly), but not trunk and extremity tumors. CONCLUSION: While our cohort of patients with MPNST are typically relatively young and healthy, 5-year OS is only 52%. Notably, age extremes, large tumor size, and certain treatment regimens are associated with worse outcomes. While AJCC 8 staging guidelines may have some value in predicting OS in head and neck tumors, they do not reliably risk stratify patients with trunk and extremity MPNST. Ultimately, MPNST is associated with high mortality with few modifiable risk factors, and survival may not be adequately predicted by current staging systems.

Canine Spindle Cell Mammary Tumor: A Retrospective Study of 67 Cases.

Canine spindle cell mammary tumor (CSCMT) is an infrequent canine mammary tumor (CMT) composed of spindle or fusiform cells, which represents a challenge for pathologists and clinicians. Mammary tumors submitted for histopathology from 1998 to 2013 and compatible with CSCMTs were retrospectively selected. The tumors were diagnosed based on the hematoxylin and eosin (HE)-stained section; malignant tumors were graded using a canine soft tissue sarcoma grading scheme and a canine mammary tumor grading scheme, and they were further assigned a diagnosis based on immunohistochemistry (IHC) for pancytokeratin, cytokeratin 14, p63, calponin, vimentin, Ki-67, CD31, desmin, myosin, smooth muscle actin, glial fibrillary acidic protein, and S-100. The origin of the tumors was assessed as mammary, skin, or unknown. The prevalence of CSCMT was 1% of all CMTs. CSCMTs included 3 benign tumors (1 angioma and 2 benign myoepitheliomas) and 67 malignant tumors that after IHC were diagnosed as malignant myoepithelioma (64%), carcinoma and malignant myoepithelioma (19%), hemangiosarcoma (8%), undifferentiated sarcoma (5%), peripheral nerve sheath tumor (3%), and fibrosarcoma (2%). The diagnosis based on the HE-stained section differed from the diagnosis after IHC in 75% of the malignant cases. The majority of malignant CSCMTs were solitary (57%) large tumors (6.42 ± 3.92 cm) with low metastatic potential and high survival rate (8% tumor-related mortality). Higher sarcoma grade was associated with older age (P = .034) and greater tumor size (P = .037). Malignant CSCMTs need to be evaluated by IHC to ensure the histotype and the relatively benign clinical behavior, despite their large size.

Pediatric malignancies in neurofibromatosis type 1: A population-based cohort study.

Neurofibromatosis type 1 (NF1) is a cancer predisposition syndrome with an incidence of 1:2,000. Patients with NF1 have an increased cancer risk and mortality, but there are no population-based cohort studies specifically investigating the risk of childhood malignancies. We used the Finnish NF1 cohort to analyze the incidence, risk and prognosis of malignancies in NF1 patients <20 years of age. Persons born in 1987-2011 were included, and 524 persons were followed through the files of the Finnish Cancer Registry from birth up to age 20 years. This amounted to 8,376 person years. Fifty-three patients had cancer <20 years of age, yielding a standardized incidence ratio (SIR) of 35.6. The most frequent location of pediatric cancers was the central nervous system (CNS); there were 45 cases and the SIR was 115.7. Exclusion of 22 optic pathway gliomas (OPGs) gave an SIR of 59.1 for the CNS and 21.6 for all cancers. There were nine malignant peripheral nerve sheath tumors (MPNSTs); their cumulative risk was 2.7% by age 20. No cases of leukemia were observed. NF1 patients showed considerable excess mortality with a standardized mortality ratio (SMR) of 73.1. The survival of NF1 patients with CNS tumors other than OPGs did not differ from that of non-NF1 controls (HR 0.64, 95% CI 0.23 to 1.76). In conclusion, brain tumors in childhood and MPNSTs in adolescence are malignancies of major concern in patients with NF1. The risk for myeloid malignancies may not be as high as suggested in the literature.

An audit of the diagnosis and reporting of soft tissue sarcomas at the Lagos University Teaching Hospital.

BACKGROUND: : The effective management of patients with cancer is predicated on the right diagnoses and other relevant parameters included in the pathology report. This is particularly important in soft tissue pathology where arriving at the right diagnosis is often challenging. The aim of this study, therefore, was to perform an audit of sarcoma diagnosis and reporting in our institution. METHODS: Slides of soft tissue sarcomas diagnosed in our institution over a 5-year period were reviewed with specialist soft tissue pathologists. Ancillary immunohistochemistry and fluorescent in situ hybridization were performed where necessary. The contents of the reports were assessed using a diagnostic checklist developed by the Association of Directors of Anatomic and Surgical Pathology. RESULTS: Fifty-five of the 62 patients studied (88.7%) were correctly identified as sarcomas. However, the correct diagnoses were made in only 27 patients (43.6%). Kaposi sarcoma and dermatofibrosarcoma protuberans were the most recognized sarcomas, while leiomyosarcoma, myxofibrosarcoma, and malignant peripheral nerve sheath tumor were the least recognized sarcomas. The most reported parameters included the histologic type (100%) and size (89.7%), while the percentage of necrosis (0%) and the stage (0%) were the least reported parameters. CONCLUSION: A pattern based approach is important for the accurate diagnosis of soft tissue sarcomas. Some essential prognostic parameters and information needed for management were not included in the histopathology reports. The adoption of a structured reporting format and multidisciplinary team meetings will help to ensure the inclusion of such important information in the pathology report.

Management of peripheral nerve sheath tumors: 17 years of experience at Toronto Western Hospital.

OBJECTIVE A surgical series of 201 benign and malignant peripheral nerve sheath tumors (PNSTs) was assessed to characterize the anatomical and clinical presentation of tumors and identify predictors of neurological outcome, recurrence, and extent of resection. METHODS All surgically treated PNSTs from the Division of Neurosurgery at Toronto Western Hospital from 1993 to 2010 were reviewed retrospectively. Data were collected on patient demographics, clinical presentation, surgical technique, extent of resection, postoperative neurological outcomes, and recurrence. RESULTS One hundred seventy-five patients with 201 tumors had adequate follow-up for analysis. There were 182 benign and 19 malignant PNSTs. Of the benign lesions, 133 were schwannomas, 21 of which were associated with a diagnosis of schwannomatosis. There were 49 neurofibromas, and 26 were associated with neurofibromatosis Type 1 (NF1). Patients presenting with schwannomas were significantly older than those with neurofibromas. Schwannomas were more readily resected than neurofibromas, with the extent of resection of the former influenced by tumor location. Patients with benign PNSTs typically presented with a painful mass and less frequently with motor deficits. The likelihood of worsened postoperative motor function was decreased in patients with fully resected tumors or preoperative deficits. Recurrence of schwannomas and neurofibromas were seen more frequently in patients diagnosed with NF3 and NF1, respectively. Subtotal resection was associated with the increased recurrence of all benign lesions. CONCLUSIONS Outcomes following resection of benign PNSTs depend on tumor histopathology, tumor location, and genetic predisposition syndrome. Gross-total resection should be attempted for benign lesions where possible. The management of malignant PNSTs remains challenging, requiring a multimodal approach.

Malignant Peripheral Nerve Sheath Tumors are not a Feature of Neurofibromatosis Type 2 in the Unirradiated Patient.

BACKGROUND: The published literature suggests that malignant peripheral nerve sheath tumors (MPNST) occur at increased frequency in neurofibromatosis type 2 (NF2). A recent review based on incidence data in North America showed that 1 per 1000 cerebellopontine angle nerve sheath tumors were malignant. OBJECTIVE: To determine whether MPNST occurred spontaneously in NF2 by reviewing our NF2 database. METHODS: The prospective database consists of 1253 patients with NF2. One thousand and nine are known to be alive at last follow-up. The presence and laterality/pathology of vestibular schwannoma at diagnosis and last follow-up was sought. RESULTS: There were no cases of spontaneous MPNST with 2114 proven (n = 1150) and presumed benign (n = 964) vestibular schwannomas found. Two patients had developed MPNST (1 presumed) after having previously undergone stereotactic radiosurgery for a vestibular schwannoma. CONCLUSION: In this series, and from the literature, malignant transformation of a vestibular schwannoma was not a feature of NF2 in the unirradiated patient. NF2 patients should not be told that they have an increased risk of malignant change in a vestibular schwannoma unless they undergo radiation treatment. However, very much larger datasets are required before it can be determined whether there is any association between NF2 and MPNST in the unirradiated patient.

[Soft tissue tumors : Epidemiology, classification and staging]. / Weichteiltumoren : Epidemiologie, Klassifikation und Stadieneinteilung.

Benign, intermediate and malignant soft tissue tumors can be differentiated histologically. Furthermore, the tumors can be subdivided according to their linear differentiation. In the new World Health Organization (WHO) classification of soft tissue tumors from 2013 changes have been made relating to the allocation of known entities, e. g. undifferentiated sarcomas have been formed into a new subgroup and are no longer assigned to the fibrohistiocytic tumors. The term malignant fibrous histiocytoma has been replaced by the undifferentiated sarcoma. Furthermore, two new subgroups were incorporated, the nerve sheath tumors and gastrointestinal stromal tumors. These were previously included in the tumor classification of other organ systems. These changes in the new classification are related to the rapid increase in knowledge of the genetics and the cell biology of soft tissue tumors. Malignant soft tissue tumors only represent 1% of all malignant tumors in adults. The largest subgroup of soft tissue tumors in adults is the adipocytic tumors. The liposarcoma, which belongs to this subgroup is one of the most common malignant soft tissue tumors in adults. In childhood malignant soft tissue tumors represent 15% of malignant tumors and rhabdomyosarcoma is the most common malignant soft tissue tumor.

Neural Tumors of the Orbit -- What Is New?

Primary neural tumors of the orbit account for approximately 10% of all orbital tumors. Different tumor entities include meningiomas, optic nerve gliomas, neurofibromas, schwannomas, malignant peripheral nerve sheath tumors, and granular cell tumors. This review summarizes current concepts regarding epidemiology, clinical presentation, diagnosis, pathology, immunohistochemistry, prognosis, and treatment for neural tumors of the orbit based on the available literature.

Hybrid peripheral nerve sheath tumors: report of five cases and detailed review of literature.

BACKGROUND: Hybrid peripheral nerve sheath tumors (PNSTs) have been recognized recently and were first included in the 4th edition of World Health Organization (WHO) Classification of Tumors of Soft tissue and Bone, published in 2013. These tumors show combined features of more than one type of conventional benign peripheral nerve sheath tumors. The most common combinations are those of schwannoma/perineurioma followed by combinations of neurofibroma/schwannoma and neurofibroma/perineurioma. A detailed literature review of published cases is presented. We have discussed the types and etiology, epidemiology and sites of localization, gross and microscopic appearances and immunohistochemical features of hybrid PNSTs and association of these tumors with tumor syndromes. CASE PRESENTATION: We have included five cases which were diagnosed in our department as we believe that publication of these new cases is relevant for the improved understanding of these specific tumors. Four of our five patients were males, mean age was 24 years. There was wide variation in the location of these tumors. Mean size of excised tumors was 5.5 cms in the greatest dimensions. Three out of five cases represented hybrid schwannoma/perineurioma histologically. No significant nuclear atypia, mitotic activity or necrosis seen. All five cases were completely excised. All five patients are alive and well at the time of writing with no recurrence. CONCLUSION: Hybrid PNSTs are distinct tumors and are usually benign. However, rare case reports have described local recurrence and at least two recent case reports have described malignant transformation in these tumors. Further studies on large number of cases are required to determine the exact pathogenetic basis of these tumors.

Neurological outcomes and surgical complications in 221 spinal nerve sheath tumors.

OBJECTIVE Among all primary spinal neoplasms, approximately two-thirds are intradural extramedullary lesions; nerve sheath tumors, mainly neurofibromas and schwannomas, comprise approximately half of them. Given the rarity of these lesions, reports of surgical complications are limited. The aim of this study was to identify the rates of new or worsening neurological deficits and surgical complications associated with the resection of spinal nerve sheath tumors and the potential factors related to these outcomes. METHODS Patients were identified through a search of an institutional neuropathology database and a separate review of current procedural terminology (CPT) codes. Age, sex, clinical presentation, presence of neurofibromatosis (NF), tumor type, tumor location, extent of resection characterized as gross total or subtotal, use of intraoperative neuromonitoring, surgical complications, presence of neurological deficit, and clinical follow-up were recorded. RESULTS Two hundred twenty-one tumors in 199 patients with a mean age of 45 years were identified. Fifty-three tumors were neurofibromas; 163, schwannomas; and 5, malignant peripheral nerve sheath tumors (MPNSTs). There were 70 complications in 221 cases, a rate of 32%, which included 34 new or worsening sensory symptoms (15%), 12 new or worsening motor deficits (5%), 10 CSF leaks or pseudomeningoceles (4%), 11 wound infections (5%), 5 cases of spinal deformity (2%), and 6 others (2 spinal epidural hematomas, 1 nonoperative cranial subdural hematoma, 1 deep venous thrombosis, 1 case of urinary retention, and 1 recurrent laryngeal nerve injury). Complications were more common in cervical (36%) and lumbosacral (38%) tumors than in thoracic (18%) lesions (p = 0.021). Intradural and dumbbell lesions were associated with higher rates of CSF leakage, pseudomeningocele, and wound infection. Complications were present in 18 neurofibromas (34%), 50 schwannomas (31%), and 2 MPNSTs (40%); the differences in frequency were not significant (p = 0.834). Higher complication rates were observed in patients with NF than in patients without (38% vs 30%, p = 0.189), although rates were higher in NF Type 2 than in Type 1 (64% vs 31%). There was no difference in the use of intraoperative neuromonitoring when comparing cases with surgical complications and those without (67% vs 69%, p = 0.797). However, the use of neuromonitoring was associated with a significantly higher rate of gross-total resection (79% vs 66%, p = 0.022). CONCLUSIONS Resection is a safe and effective treatment for spinal nerve sheath tumors. Approximately 30% of patients developed a postoperative complication, most commonly new or worsening sensory deficits. This rate probably represents an inevitable complication of nerve sheath tumor surgery given the intimacy of these lesions with functional neural elements.

An association of peripheral nerve sheath tumors and lipomas.

BACKGROUND: We noticed the coexistence of peripheral nerve sheath tumors (PNST) with lipomas within a subgroup of our patients. Given the prevalence of lipomas in the general population, we sought to investigate the extent of coexistence of the two entities aiming at uncovering any plausible association between both. METHODS: A retrospective review of all peripheral nerve sheath tumors (sporadic and syndromic forms) treated by a single surgeon between January 2009 and August 2015 was done. We recorded demographics (i.e., gender, age at diagnosis, imaging information, time to diagnosis) in addition to the method of diagnosis, subtype, number and location of lipomas, if present. RESULTS: Over 6 years, 309 patients with PNST were operated/evaluated. These included 141 sporadic (schwannomas, neurofibromas) and 168 syndromic (neurofibromatosis type 1 and 2 and schwannomatosis). We found 32 patients [10.3%, 95% confidence interval (CI) = 7.43%-14.3%] with coexistent lipomas, some of whom also had a family member with lipoma (n = 3). Of these 26 had schwannomas, 3 had neurofibromas and 3 lacked definitive PNST histopathological diagnosis. Fourteen percent of patients with schwannomas and 2.9% of patients with neurofibromas had coexisting lipomas. CONCLUSION: We believe there is an increased association of peripheral nerve tumors and lipomas overall.

Orbital peripheral nerve sheath tumors.

Peripheral nerve sheath tumors of the orbit and ocular adnexa are a rare group of neoplasms hallmarked by nonspecific clinical presentations, variable tumor locations, challenging therapeutic efforts, and occasional diagnostic dilemmas. We review these tumor types and provide an updated summary on their clinical, histopathologic, radiological, and emerging molecular features.

Statistical Report of Central Nervous System Tumors Histologically Diagnosed in the Sichuan Province of China from 2008 to 2013: A West China Glioma Center Report.

BACKGROUND: Sichuan is a province in the west of China with a population of 81.4 million. This is the first statistical report of central nervous system (CNS) tumors surgically treated and histologically diagnosed in a large Chinese population. METHODS: All the patient data were obtained from 86 medical facilities, which covered the Sichuan province population. Data from patients who underwent surgery between 2008 and 2013 and corresponding histology samples were re-reviewed in the major pathology centers. All the CNS tumors were categorized according to International Classification of Diseases (ICD)-10 and ICD-O-3 classifications and reviewed manually. The tumor distribution was analyzed and stratified by gender, age, race, and tumor sites. Tumors in some ethnic minorities, such as the Tibetan people, also were analyzed. RESULTS: The final analytic dataset included 35,496 records. The top four histologic tumors were meningioma (28.51 %), pituitary adenoma (15.00 %), nerve sheath (13.77 %), and glioblastoma (11.82 %). There was a dramatically high incidence of malignant tumor in males. The median age at diagnosis ranged from 13 years (pineal region tumors) to 56 years (metastatic brain tumors). Most of the tumors in the insular lobe or cerebellum were low grade, whereas those in the thalamus or basal ganglia were likely to be high grade. The incidence of malignant tumors or high-grade gliomas in the Tibetans was significantly lower than in the Chinese Han population. CONCLUSION: This report is a preliminary statistical analysis of brain and spinal tumors in a large Chinese population and may serve as a useful resource for clinicians, researchers, and patients' families.

Results of Spinal Fusion After Spinal Nerve Sheath Tumor Resection.

INTRODUCTION: Intradural extramedullary spine tumors, approximately one-half of which are peripheral nerve sheath tumors (PNSTs), comprise two-thirds of primary spinal neoplasms. Given the rarity of PNSTs and the restricted indications for adding fusion to laminectomy for tumor resection, analyses of spinal fusion outcomes are limited. METHODS: Demographics, clinical presentation, tumor characteristics, extent of resection, spinal fusion, complications, and clinical follow-up were recorded retrospectively. RESULTS: A total of 221 tumors in 199 patients were identified (53 neurofibromas, 163 schwannomas, 5 malignant PNSTs); 78 patients underwent fusion (70 instrumented; 8 noninstrumented). Fusion rates were higher for extradural versus intradural lesions (60% vs. 29%; P = 0.001) and for tumors involving the cervicothoracic junction (88% vs. 31%, P < 0.001). There was no difference in fusion rates based on pathology. Rates of new or worsening sensory (19% in fusion vs. 13% in nonfused) or motor deficits (8% in fused vs. 4% in nonfused), wound infection (3% in fused vs. 6% in nonfused) and cerebrospinal fluid (CSF) leak or pseudomeningocele (6% in fused vs. 4% in nonfused) were not statistically different. There were 10 fusion-related complications: 6 adjacent segment disease, 3 implant failures, and 1 pseudoarthrosis. Mean time from surgery to last follow-up was 32 months. CONCLUSIONS: In this cohort, PNSTs in the cervical spine, spanning the cervicothoracic junction, and extradural tumors were associated with higher rates of spinal fusion. Fusion was not associated with new or worsening motor/sensory deficits, CSF leak, pseudomeningocele, wound infection, or spinal deformity. Overall, spinal fusions were well tolerated and did not increase the risk of postoperative complications.

Malignant peripheral nerve sheath tumors of the eighth cranial nerve arising without prior irradiation.

OBJECTIVE Malignant peripheral nerve sheath tumors (MPNSTs) of the eighth cranial nerve (CN) are exceedingly rare. To date the literature has focused on MPNSTs occurring after radiation therapy for presumed benign vestibular schwannomas (VSs), while MPNSTs arising without prior irradiation have received little attention. The objectives of the current study are to characterize the epidemiology, clinical presentation, disease course, and outcome using a large national cancer registry database and a systematic review of the English literature. Additionally, a previously unreported case is presented. METHODS The authors conducted an analysis of the Surveillance, Epidemiology, and End Results (SEER) database, a systematic review of the literature, and present a case report. Data from all patients identified in the SEER database with a diagnosis of MPNST involving the eighth CN, without a history of prior radiation, were analyzed. Additionally, all cases reported in the English literature between January 1980 and March 2015 were reviewed. Finally, 1 previously unreported case is presented. RESULTS The SEER registries identified 30 cases between 1992 and 2012. The average incidence was 0.017 per 1 million persons per year (range 0.000-0.0687 per year). The median age at diagnosis was 55 years, and 16 (53%) were women. Thirteen cases were diagnosed upon autopsy. Of the 17 cases diagnosed while alive, the median follow-up was 118 days, with 3 deaths (18%) observed. When compared with the incidence of benign VS, 1041 VSs present for every 1 MPNST arising from the eighth CN. Including a previously unreported case from the authors' center, a systematic review of the English literature yielded 24 reports. The median age at diagnosis was 44 years, 50% were women, and the median tumor size at diagnosis was 3 cm. Eleven patients (46%) reported isolated audiovestibular complaints typical for VS while 13 (54%) exhibited facial paresis or other signs of a more aggressive process. Treatment included microsurgery alone, microsurgery with adjuvant radiation, or microsurgery with chemoradiation. Sixty-one percent of patients receiving treatment experienced recurrence, 22% of which were diagnosed with drop metastases to the spine. Ultimately, 13 patients (54%) died of progressive disease at a median of 3 months following diagnosis. The ability to achieve gross-total resection was the only feature that was associated with improved disease-specific survival. CONCLUSIONS MPNSTs of the eighth CN are extremely rare and portend a poor prognosis. Nearly half of patients initially present with findings consistent with a benign VS, often making an early diagnosis challenging. In light of these data, early radiological and clinical follow-up should be considered in those who elect nonoperative treatment, particularly in patients with a short duration of symptoms or atypical presentation. These data also provide a baseline rate of malignancy that should be considered when estimating the risk of malignant transformation following stereotactic radiosurgery for VS.