Meningothelioma as the predominant histological subtype of midline skull base and spinal meningioma

Review of meningioma diagnosis and management

Meningiomas are the most common intracranial tumors in adult patients. Although the majority of meningiomas are diagnosed as benign, approximately 20% of cases are high-grade tumors that require significant clinical treatment. The gold standard for grading central nervous system tumors comes from the World Health Organization Classification of Tumors of the central nervous system. Treatment options also depend on the location, imaging, and histopathological features of the tumor. This review will cover diagnostic strategies for meningiomas, including 2021 updates to the World Health Organization's grading of meningiomas. Meningioma treatment plans are variable and highly dependent on tumor grading. This review will also update the reader on developments in the treatment of meningiomas, including surgery, radiation therapy and monoclonal antibody treatment.

Symptom burden and surgical outcome in non-skull base meningiomas

Purpose

Non-skull base meningiomas (NSBM) are a distinct entity and frequently present with focal neurological deficits. This study was designed to analyze functional and oncological outcome following microsurgical tumor resection in patients with NSBM.

Patients and methods

An analysis of 300 patients that underwent NSBM resection between 2003 and 2013 was performed. Assessment measures for functional outcome were Karnofsky Performance Scale (KPS), Medical Research Council - Neurological Performance Scale (MRC-NPS), and improvement rates of focal deficits and seizures. The extent of resection; recurrence-free survival (RFS) and tumor-specific survival (TSS) were also determined.

Results

Impaired KPS and MRC-NPS were present in 73.3% and 45.7%, respectively. Focal neurological deficits were recorded in 123 patients (41.0%), with hemiparesis (21.7%) and aphasia (9.3%) the most prevalent form of impairment. Most meningiomas were localized at the convexity (64.0%), followed by falcine tumors (20.3%). Both KPI and MRC-NPS scores were significantly improved by surgical resection. Postoperative improvement rates of 96.6%, 89.3%, 72.3%, 57.9%, and 27.3% were observed for aphasia, epilepsy, hemiparesis, cranial nerve, and visual field deficits, respectively. Long-term improvement was achieved in 83.2%, 89.3%, 80.0%, 68.4% and 54.6% of patients, respectively. Gross total resection (GTR) over subtotal resection (STR) significantly improved preoperative seizures and visual field deficits and correlated with reduced risk of new postoperative hemiparesis. Poor Simpson grade was the only significant prognostic factor in multivariate analysis for long-term functional deficit, which occurred in 7.3%. Median RFS was 45.9 months (6.0 - 151.5 months), while median TSS was 53.7 months (3.1 – 153.2 months). Both WHO grade (p= 0.001) and Simpson classification (p= 0.014 and p= 0.031) were independent significant prognostic factors for decreased RFS and TSS by multivariate analysis, respectively. Furthermore, tumor diameter > 50 mm (p= 0.039) significantly correlated with decreased TSS in multivariate analysis.

Conclusion

Surgical resection significantly and stably improves neurological deficits in patients with NSBM.

Clinical Significance of Molecular Alterations and Systemic Therapy for Meningiomas: Where Do We Stand?

Simple Summary

Meningiomas are the most frequent intracranial tumors and comprise a heterogeneous spectrum of diseases, ranging from small, asymptomatic tumors that do not need treatment to large, symptomatic ones causing seizures or neurological deficits that require surgery and/or radiotherapy. Systemic therapy is reserved for progressive or recurrent meningiomas when surgery and/or radiotherapy options have been exhausted, with only modest activity in terms of disease control and survival. Novel molecular alterations are correlated with grading, location, and prognosis of meningiomas. Moreover, some of these driver alterations regulate meningioma growth and progression and may be targeted by specific drugs that are under investigation in clinical trials. Lastly, the microenvironment surrounding meningiomas may also contribute to regulating tumor growth: in particular, PD-L1 and/or M2 macrophage expression may represent a target for immunotherapy.

Abstract

Meningiomas are common intracranial tumors that can be treated successfully in most cases with surgical resection and/or adjuvant radiotherapy. However, approximately 20% of patients show an aggressive clinical course with tumor recurrence or progressive disease, resulting in significant morbidity and increased mortality. Despite several studies that have investigated different cytotoxic agents in aggressive meningiomas in the past several years, limited evidence of efficacy and clinical benefit has been reported thus far. Novel molecular alterations have been linked to a particular clinicopathological phenotype and have been correlated with grading, location, and prognosis of meningiomas. In this regard, SMO, AKT, and PIK3CA mutations are typical of anterior skull base meningiomas, whereas KLF4 mutations are specific for secretory histology, and BAP1 alterations are common in progressive rhabdoid meningiomas. Alterations in TERT, DMD, and BAP1 correlate with poor outcomes. Moreover, some actionable mutations, including SMO, AKT1, and PIK3CA, regulate meningioma growth and are under investigation in clinical trials. PD-L1 and/or M2 macrophage expression in the microenvironment provides evidence for the investigation of immunotherapy in progressive meningiomas.

Diagnostic, therapeutic, and prognostic implications of the 2021 World Health Organization classification of tumors of the central nervous system

The 2016 revised fourth edition of the World Health Organization (WHO) classification of central nervous system (CNS) tumors incorporated molecular features with histologic grading, revolutionizing how oncologists conceptualize primary brain and spinal cord tumors as well as providing new insights into their management and prognosis. The 2021 revised fifth edition of the WHO classification further integrates molecular alterations for CNS tumor categorization, updating current understanding of the pathophysiology of many of these disease entities. Here, the authors review changes in the new classification for the most common primary adult tumors-gliomas (including astrocytomas, oligodendrogliomas, and ependymomas) and meningiomas-highlighting the key genomic alterations for each group classification to help clinicians interpret them as they consider therapeutic options-including clinical trials and targeted therapies-and discuss the prognosis of these tumors with their patients. The revised, updated 2021 WHO classification also further integrates molecular alterations in the classification of pediatric CNS tumors, but those are not covered in the current review.

Clinical features and long-term outcomes of pediatric meningiomas

OBJECTIVE

Pediatric meningiomas are relatively rare and have atypical clinical features compared to adults. The purpose of this work is to report our 15-year experience in the management of pediatric meningiomas and assess their clinical characteristics, pathological features, and prognostic factors.

METHODS

A total of 40 children (age ≤ 15 years) who were diagnosed as pediatric meningiomas were enrolled in this study. Patient information including clinical presentation, gender, age at time of diagnosis, histopathological features, tumor location, tumor volume, treatment methods, and follow-up data were extracted and analyzed.

RESULTS

The mean age at diagnosis was 10.78 ± 3.50 years (range 2-15 years) in 40 patients with a male to female ratio of 1:1.11. Headache, epilepsy, visual disturbance, and limb weakness are common clinical manifestations. Two patients had multiple intracranial meningiomas. Fourteen (33.3%) of pediatric meningiomas were high grade meningiomas. Seven patients (17.5%) were treated with STR, while GTR was achieved in 33 patients (82.5%). The mean follow-up period was 82.1 months (range 9-173 months). Recurrence occurred in 9 patients (22.5%), and 5 patients (12.5%) passed away.

CONCLUSION

The incidence of pediatric meningiomas increases with advancing age. In pediatric patients, the percentage of high-grade tumors is higher than adults. Younger children were more likely to have high-grade meningiomas, while patients with tumors located in skull base or parasagittal/falx tend to have low-grade meningiomas. The WHO grade III meningiomas were significantly correlated with poor prognosis. Adjuvant radiotherapy after surgery can improve prognosis and may be a potential treatment strategy in children with malignant meningiomas.

Meningiomas from a developmental perspective: exploring the crossroads between meningeal embryology and tumorigenesis

Meningiomas are tumors arising from the meninges and represent the most frequent central nervous system tumors in adults. Recent large-scale genetic studies and preclinical meningioma mouse modelling led to a better comprehension of meningioma development and suggested evidences of close relationships between meningeal embryology and tumorigenesis. In this non-systematic review, we summarize the current knowledge on meningeal embryology and developmental biology, and illustrate how meningioma tumorigenesis is deeply related to meningeal embryology, concerning the potential cell of origin, the role of reactivation of embryonic stem cells, the influence of the embryonic tissue of origin, and the parallelism between topography-dependant molecular pathways involved in normal meninges and in meningioma development. Our study emphasizes why future studies on meningeal embryology are mandatory to affine our comprehension of mechanisms underlying meningioma initiation and development.

Clinical features of newly developed NF2 intracranial meningiomas through comparative analysis of pediatric and adult patients

OBJECTIVE

NF2 patients can develop new meningiomas throughout their lifetime. Little is known about the clinical features of newly developed NF2 meningiomas. In this study, we analyzed newly developed NF2 meningiomas in a large patient population.

PATIENTS AND METHODS

Among 452 NF2 patients, the location patterns of 81 pediatric and 939 adult NF2 meningiomas were compared to find the predominant locations of newly developed meningiomas in adulthood. The clinical features of 39 newly developed meningiomas in 24 NF2 patients were summarized. Clinical risk factors of NF2 meningioma growth rates were analyzed.

RESULTS

Pediatric patients had significantly more intracranial meningiomas than adult patients at the skull base (except for the petrosal region) (p < 0.0063). Adult patients had significantly more cranial meningiomas than pediatric patients at the parasagittal, parafalcine (middle & posterior), and frontal/parietal/cerebellar convex surfaces (p < 0.0063). Newly developed NF2 meningiomas in adults tended to occur at different locations than the locations of NF2 meningiomas in pediatric patients. New meningiomas could develop at various ages. Ninety-five NF2 patients were imaged and followed up for at least one year. Twenty-four patients (25.3 %) developed 39 new meningiomas during the follow-up period. They usually had initial meningiomas when new meningiomas occurred. The number of newly developed meningiomas per patient and the petrosal location were significantly associated with both the absolute and relative annual growth rates (p < 0.05).

CONCLUSIONS

The number of newly developed NF2 meningiomas seems to be a clinical marker of NF2 disease severity. In adults, new NF2 meningiomas tend to occur in patients with initial meningiomas. The predominant locations of newly developed NF2 meningiomas seem to be the parasagittal, parafalcine (middle/posterior), and frontal/parietal/cerebellar convex surfaces.

Comprehensive analysis of meningioma in the first two decades of life: A systematic review

PURPOSE

To evaluate the relationship between meningioma histological subtype and tumor site in under-20 year-olds.

METHODS

A review of the literature on meningioma during the first 2 decades of life was carried out through a Medline search up to February 2019. To evaluate the adult population, a cross-sectional study was conducted on patients operated on between 2000 and 2014 in a single institution. Exclusion criteria comprised: series reports and papers that lacked detailed description of clinical findings, neuroimaging confirmation of tumor location, and/or at least 5 years' follow-up.

RESULTS

One hundred and seven manuscripts were included, for 365 under-20 year-old patients: 200 male, and 164 female. Histopathology found 197 cases (53.9%) of WHO grade I meningioma, with predominance of meningothelial (41.1%) and transitional (30.9%) subtypes; 123 (33.7%) grade II, and 45 (12.3%) grade III. For 65 (18.25%) of the 356 cases, recurrence was documented, with only 24 deaths (6.7%).

CONCLUSION

Meningioma in this population presented 2 differences compared to the adult population: male predominance, and high incidence of atypical meningioma. Surgery was the primary treatment. Adjuvant radiotherapy is controversial in the literature.

WHO grade, proliferation index, and progesterone receptor expression are different according to the location of meningioma

BACKGROUND

Meningiomas may show a different WHO grade and variable biological and clinical behaviors. The aim of the present study is to assess whether WHO grade, proliferation index, progesterone receptor (PR) expression, histological subtype, neuroradiological features, and the recurrence rate differ depending on the tumor location.

METHODS

Three hundred meningiomas operated on from 2006 to 2016 were reviewed. The WHO grade (2007 classification), Ki67-MIB1, progesterone receptor expression, and histological subtype were reexamined and correlated to the meningioma location, classified as medial skull base, lateral skull base, non-skull base, and spinal.

RESULTS

Non-skull base and lateral skull base meningiomas showed significantly higher rates of atypical WHO II forms (34% and 25.5% respectively) than medial skull base (12.5%) and spinal ones (7%) (p = 0.0003) and also higher rates of tumors with Ki67-Li > 4% (42% and 38% vs 22% and 14%) (p = 0.0031). The rate of meningiomas with PR expression ≤ 50% was significantly lower in medial skull base (25%) than in non-skull base (48%) (p = 0.009). Meningothelial and transitional meningiomas were more frequent at the skull base (68.5% and 54.5%, respectively), the fibroblastic subtype at the non-skull base (48.5%), and the psammomatous at the spinal canal (50%) (p < 0.00001). Medial skull base and spinal meningiomas showed significantly lower size (p < 0.00001), lower rates of cases with lost arachnoid interface (p = 0.0022), and significantly lower recurrence rates (p = 0.0035) than lateral skull base and non-skull base meningiomas.

CONCLUSION

Medial skull base meningiomas show lower size, lower rate of atypical forms, lower Ki67-Li values, and significantly higher PR expression than those at the lateral skull base and non-skull base. This corresponds to lesser aggressiveness and lower recurrence rates.

Histomolecular characterization of intracranial meningiomas developed in patients exposed to high-dose cyproterone acetate: an antiandrogen treatment

Background

Meningiomas are the most common primary intracranial tumors in adults. The relationship between meningiomas and exogenous sex hormones such as cyproterone acetate (CPA) is well documented, yet the underlying mechanisms remain unknown. Defining the histomolecular status of meningiomas developed on CPA would help us to better understand the oncogenesis of these tumors.

Methods

We identified 30 patients operated for a meningioma after long-term high-dose CPA therapy and with a history of CPA discontinuation before establishing the indication for surgical intervention. We used array-comparative genomic hybridization (to characterize copy number changes in those 30 meningiomas and subsequently performed next-generation sequencing with the National Institute of Cancer (INCa) solid tumor panel, which is a targeted panel of clinically actionable genes. We also examined grade, type, and clinical features.

Results

We identified AKT1 mutations or PIK3CA mutations in 33.3% of CPA meningiomas. AKT1 and PIK3CA mutations were mutually exclusive. Enrichment in oncogenic PIK3CA mutations in the CPA cohort was detected. CPA meningiomas showed chromosomal stability and were located mainly in the skull base. Ninety percent of CPA meningiomas were low-grade meningiomas and 63.4% were meningotheliomas. Half of our CPA cohort had microcystic components.

Conclusion

Our study shows that low-grade meningothelial meningiomas of the skull base are predominant in CPA meningiomas. We identified PIK3CA/AKT1 pathway as a hypothetical actor in onco-pharmacological interaction between meningiomas and CPA. This signaling pathway could be an interesting target for precision medicine trials in meningioma patients who have been subjected to CPA. Our results could invite the scientific community to review the current classification of meningiomas and to evolve toward more specific histomolecular classification.

Natural history of intraventricular meningiomas: systematic review

Review the data published on the subject to create a more comprehensive natural history of intraventricular meningiomas (IVMs). A Medline search up to March 2018 using "intraventricular meningioma" returned 98 papers. As a first selection step, we adopted the following inclusion criteria: series and case reports about IVMs, as well as papers written in other languages, but abstracts written in English were evaluated. Six hundred eighty-one tumors were evaluated from 98 papers. The majority of the tumors were located in the lateral ventricles (602-88.4%), fourth ventricle (59-8.7%), and third ventricle (20-2.9%). These tumors accounted for a mortality rate of 4.0% (25 deaths) and a recurrence rate of 5.3% (26 recurrences). The majority of the tumors were grade I (89.8%) and consisted of the following subtypes: fibrous, 39.7% (n = 171); transitional, 22.0% (n = 95); meningothelial, 18.6% (n = 80); angiomatosus, 3.2% (n = 14); psammomatous, 2.6% (n = 11); and others, 13.9% (n = 60). Forty-five patients (7.4%) presented with grade II (GII) tumors, and 17 patients (2.8%) presented with grade III (GIII) tumors. These tumors follow the histopathological distribution of meningiomas in general, with the exception of the higher prevalence of the fibrous subtype, possibly due to its embryonic origin. Recurrence and mortality were lower than in other localizations likely due to a complete surgical resection rate than in the convexity and skull base, which suggests that GTR is the gold standard for the management of IVMs.

Safety and efficacy of single-fraction gamma knife radiosurgery for benign confined cavernous sinus tumors: our experience and literature review

Gamma knife radiosurgery (GKRS) has emerged as a suitable primary treatment option for confined cavernous sinus tumors (CSTs) and residual/recurrent benign tumors extending from the surrounding neighborhood. The aim of this review was to further investigate the safety and efficacy of single-fraction GKRS for primary confined CSTs (hemangioma, meningioma, and schwannoma). This was a retrospective analysis of 16 patients of CSTs, primarily treated with GKRS between 2009 and 2017. The patients underwent follow-up clinical and radiological evaluation at a regular interval. Data on clinical and imaging parameters were analyzed. The published literature on GKRS for CSTs was reviewed. There were total 16 patients (eight meningiomas, seven hemangiomas, and one schwannoma). Patients presented with a headache (56.3%), ptosis (50%), and/or restricted extraocular movements (50%). There was 46.6% tumor volume (TV) reduction after single-fraction GKRS. Hemangiomas showed best TV reduction (64% reduction at > 3-year follow-up) followed by schwannoma (41.5%) and meningioma (25.4%). 56.3% of patients developed transient hypoesthesia in trigeminal nerve distribution. 44.4% of patients became completely pain-free. Among cranial nerves, the superior division of the oculomotor nerve showed best outcome (ptosis 62.5%) followed by an improved range of EOM. There was no adverse event in the form of new-onset deficit, vascular complication, or malignant transformation except for one out of the field failures. Among available treatment options, GKRS is the most suitable option by virtue of its minimally invasive nature, optimal long-term tumor control, improvement in cranial neuropathies, cost-effectiveness, favorable risk-benefit ratio, and minimal long-term complications.

Advances in meningioma genetics: novel therapeutic opportunities

Meningiomas currently are among the most frequent intracranial tumours. Although the majority of meningiomas can be cured by surgical resection, ∼20% of patients have an aggressive clinical course with tumour recurrence or progressive disease, resulting in substantial morbidity and increased mortality of affected patients. During the past 3 years, exciting new data have been published that provide insights into the molecular background of meningiomas and link sites of tumour development with characteristic histopathological and molecular features, opening a new road to novel and promising treatment options for aggressive meningiomas. A growing number of the newly discovered recurrent mutations have been linked to a particular clinicopathological phenotype. Moreover, the updated WHO classification of brain tumours published in 2016 has incorporated some of these molecular findings, setting the stage for the improvement of future therapeutic efforts through the integration of essential molecular findings. Finally, an additional potential classification of meningiomas based on methylation profiling has been launched, which provides clues in the assessment of individual risk of meningioma recurrence. All of these developments are creating new prospects for effective molecularly driven diagnosis and therapy of meningiomas.

A comparison of clinicopathological features and surgical outcomes between pediatric skull base and non-skull base meningiomas

OBJECT

The purpose of this study is to analyze and compare the clinicopathological characteristics and surgical outcomes between skull base and non-skull base meningiomas in pediatric population.

METHODS

We retrospectively analyzed a total of 140 cases of pediatric meningiomas surgically treated in our department from January 2005 to July 2015 and compared the clinicopathological characteristics and surgical outcomes between skull base and non-skull base meningiomas.

RESULTS

Of all the pediatric meningiomas, 50 (35.8 %) were located at the skull base and 90 (64.2 %) were located at the non-skull base. Skull base and non-skull base meningiomas had a similar sex distribution (male/female = 1:1 in skull base meningiomas and male/female = 1.5:1 in non-skull base meningiomas) (P = 0.288) and high-grade meningioma occurrence rate (P = 0.569). In addition, the mean age of non-skull base meningiomas was 12.5 years which was younger than that of skull base meningiomas (14.2 years) (P = 0.019), and the preoperative tumor size was smaller in skull base (mean size = 4.7 cm in skull base meningiomas and mean size = 5.7 cm in non-skull base meningiomas) (P = 0.020). Gross total resection was achieved in 64 non-skull base patients (73.9 %) and 26 skull base patients (52 %) (P = 0.046). Patients with gross total resection had better progression free survival (PFS) than those with subtotal resection.

CONCLUSION

Pediatric skull base and non-skull base meningiomas are similar in sex distribution and high-grade meningioma occurrence rate. In comparison with non-skull base ones, pediatric skull base meningiomas occur at elder age and are smaller in size and they are more likely to be incompletely resected. Gross total resection and early treatment are recommended to prolong PFS of pediatric patients.

Somatic AKT1 mutations cause meningiomas colocalizing with a characteristic pattern of cranial hyperostosis

Somatic genetic mutations in meningiomas are associated with histologic subtypes, anatomical location, and grade. Concomitant hyperostosis occurs with some meningiomas and the pathogenesis is not well understood. Cranial hyperostosis and meningiomas are common in patients with Proteus syndrome, which is caused by a somatic activating mutation in AKT1 c.49G>A. This same mutation has also been found in 6-9% of sporadic non-syndromic meningiomas. Sixty-one patients with Proteus syndrome meeting clinical diagnostic criteria were evaluated at the NIH from 1997 to 2014. Of these 61, 52 had a somatic activating mutation (c.49G>A, p.Glu17Lys) in AKT1 confirmed from affected tissue samples. Photographs, physical examination and/or autopsy, X-rays, CT, and/or MRI scan of the head were reviewed in 29/52 patients. Of the 29 patients, the most common intracranial tumor was meningioma, all co-localizing with cranial hyperostosis, and diagnosed at younger ages than typical for isolated, non-syndromic meningiomas. These patients had progressive cranial overgrowth that consisted primarily of diploic space expansion, and was characterized by unilateral, parasagittal, and frontal bone involvement. We hypothesize that sporadic meningothelial and transitional subtype meningiomas are a forme fruste or microform of Proteus syndrome, and activation of the AKT/PI3K pathway drives hyperostosis in both non-syndromic, and Proteus-related meningiomas. © 2016 The Authors. American Journal of Medical Genetics Part A Published by Wiley Periodicals, Inc.

Biology and clinical management challenges in meningioma

Meningiomas are the most frequently occurring intracranial tumors. They are characterized by a broad spectrum of histopathologic appearance. Molecular alterations driving meningioma development, which affect the NF2 gene, are found in roughly 50% of patients. Rare genetic events in benign meningiomas are mutations in TRAF7, KLF4, AKT1, and SMO; all of these mutations are exclusive of NF2 alterations. Progression to a clinically aggressive meningioma is linked to inactivation of CDKN2A/B genes, and a plethora of signaling molecules have been described as activated in meningiomas, which supports the concept of successful clinical use of specific inhibitors. Established treatments include surgical resection with or without radiotherapy delivered in a single fraction, a few large fractions (radiosurgery), or multiple fractions (fractionated radiotherapy). For recurrent and aggressive tumors, inhibitors of the vascular endothelial growth factor (VEGF) pathway, such as vatalinib, bevacizumab, and sunitinib, showed signs of activity in small, uncontrolled studies, and prospective clinical studies will test the efficacy of the tetrahydroisoquinoline trabectedin and of SMO and AKT1 inhibitors.

Surgical management of ventrally based lower cervical (subaxial) meningiomas through the lateral approach: Report on 16 cases

OBJECTIVES

Spinal meningiomas are benign and relatively rare tumors. These tumors present about only 25% of primary spinal tumors. Although spinal meningiomas are considered as slowly growing benign tumors, yet they may cause devastating neurological deficits rendering patients crippled. This study describes performing a posterolateral approach to surgically treat anterior based cervical meningioma. We hereby report on 16 cases operated upon using this approach, and we present our results and display some of our cases with special emphasis on achieving total resection, rate of recurrence and the neurological outcome.

PATIENTS AND METHODS

The study reports on 16 patients who underwent surgery for anterior based cervical meningioma. Data regarding age, sex, duration and type of symptoms, levels, topographical locations, surgical results, and histological features are presented.

RESULTS

The age ranged between 19 and 78 years old with a mean age of 48.3 years. The initial symptom among most patients (13 patients) was neck pain, numbness and radicular pain were found in 9, and clumsiness of the upper extremity in 7 patients. Total excision with dural coagulation was done in 11 cases, and spilt dura technique was feasible in 4 cases where the tumor together with the inner dura layer was resected. We encountered one case of atypical meningioma with Pia and arachnoid invasion which rendered total excision too risky and only subtotal resection was achieved. There were no major surgical or permanent neurological complications. Lateral mass fixation was used in 2 patients with a strictly midline anterior tumor in which a total facetectomy was done. All patients were followed up for an average of 3.6 years. Tumor recurrence was seen in 3 patients.

CONCLUSIONS

The lateral approach allows for safe and total removal of ventral cervical meningioma. This approach gives a direct avenue to the tumor without risk of destabilizing the vertebral column. The rate of recurrence is the same when using the anterior approach but is less invasive with less blood loss.

Primary Extracranial Meningioma: The Royal Pearl Experience

The extracranial occurrence of meningioma, which is a tumour of the central nervous system, is rare. Two cases of primary extracranial meningioma of the psammomatous variant are reported here. Both cases were managed successfully by endoscopic endonasal approach. Literature has been reviewed and their clinicopathological features are described.

Molecular genetics of meningiomas: Building the roadmap towards personalized therapy

New advances have recently been made in the field of molecular genetics and mouse modeling of meningiomas, opening new perspectives for future treatments. Recent genome-wide genotyping and exome sequencing studies have confirmed the pivotal role of NF2 in meningioma tumorigenesis, concerning roughly half of the tumors, and unraveled new mutations in non-NF2 meningiomas concerning AKT1, SMO, KLF4 and TRAF7. The molecular mechanisms underlying tumorigenesis of high histological grades have been progressively deciphered with the recent discovery of TERT promoter mutations in progressing tumors. A better understanding of the genetics and clinical behavior of high-grade meningiomas is mandatory in order to better design future clinical trials. New genetically engineered mouse models of benign and histologically aggressive meningioma represent a substantial resource for the establishment of relevant pre-clinical trials. By studying the mechanisms underlying these new tumorigenesis pathways and the corresponding mouse models, we should be able to offer personalized chemotherapy to patients with surgery- and radiation-refractory meningiomas in the near future.

Histological-subtypes and anatomical location correlated in meningeal brain tumors (meningiomas)

Context:

Not enough literature is available to suggest a link between the histological subtypes of intracranial meningeal brain tumors, called ‘meningiomas’ and their location of origin.

Aim:

The evidence of correlation between the anatomical location of the intracranial meningiomas and the histopathological grades will facilitate specific diagnosis and accurate treatment.

Materials and Methods:

The retrospective study was conducted in a single high-patient-inflow Neurosurgical Center, under a standard and uniform medical protocol, over a period of 30 years from December 1982 to December 2012. The records of all the operated 729 meningiomas were analyzed from the patient files in the Medical Records Department. The biodata, x-rays, angiography, computed tomography (CT) scans, imaging, histopathological reports, and mortality were evaluated and results drawn.

Results:

The uncommon histopathological types of meningiomas (16.88%) had common locations of origin in the sphenoid ridge, posterior parafalcine, jugular foramen, peritorcular and intraventricular regions, cerebellopontine angle, and tentorial and petroclival areas. The histopathological World Health Organization (WHO) Grade I (Benign Type) meningiomas were noted in 89.30%, WHO Grade II (Atypical Type) in 5.90%, and WHO Grade III (Malignant Type) in 4.80% of all meningiomas. Meningiomas of 64.60% were found in females, 47.32% were in the age group of 41-50 years, and 3.43% meningiomas were found in children. An overall mortality of 6.04% was noted. WHO Grade III (malignant meningiomas) carried a high mortality (25.71%) and the most common sites of meningiomas with high mortality were: The cerebellopontine angles, intraventricular region, sphenoid ridge, tuberculum sellae, and the posterior parafalcine areas.

Conclusion:

The correlation between the histological subtypes and the anatomical location of intracranial meningeal brain tumors, called meningiomas, is evident, but further research is required to establish the link.

Single-fraction radiosurgery of benign cavernous sinus meningiomas

OBJECT

Stereotactic radiosurgery (SRS) is an important treatment option for patients with cavernous sinus meningiomas (CSM). To analyze factors associated with local tumor control and complications after single-fraction SRS, the authors reviewed cases involving patients treated with Gamma Knife SRS between 1990 and 2008.

METHODS

Excluded were patients with WHO Grade II or III tumors, radiation-induced tumors, multiple meningiomas, neurofibromatosis Type 2, and prior or concurrent radiotherapy. Five patients were lost to follow-up and 3 patients refused research authorization. The remaining 115 patients (29 men, 86 women) had either histologically confirmed WHO Grade I (n = 46, 40%) or presumed (n = 69, 60%) CSM. The median treatment volume was 9.3 cm(3) (range 1.3-42.2 cm(3)). The median margin dose was 16 Gy (range 12-20 Gy). The median follow-up after SRS was 89 months (range 12-251 months). Thirty-nine patients (34%) had 10 or more years of follow-up after SRS.

RESULTS

Six patients (5%) had tumor progression (in field, n = 3; marginal, n = 3) at a median of 74 months (range 42-145 months) after SRS. The local tumor control rate was 99% at 5 years and 93% at 10 years after SRS. No analyzed factor was associated with local control after SRS. Fourteen patients (12%) had permanent complications at a median onset of 23 months (range 2-146 months) including trigeminal dysfunction (n = 9), diplopia (n = 2), ischemic stroke (n = 2), and hypopituitarism (n = 1). The 2-year, 5-year, and 10-year rates of complications were 7%, 10%, and 15%, respectively. Multivariate analysis found larger treatment volume (HR 1.1, 95% CI 1.02-1.2, p = 0.01) to be associated with complications after SRS. The complication rate for patients with a treatment volume of 9.3 cm(3) or less was 3% (2 of 58 cases) compared with 21% (12 of 57 cases) for patients with a treatment volume greater than 9.4 cm(3).

CONCLUSIONS

Single-fraction SRS at the radiation doses used in this series provided durable tumor control for patients with benign CSM. Larger tumor volume remains the primary factor associated with complications after single-fraction SRS of benign CSM despite advancements in SRS technique.

Long-term follow-up of 287 meningiomas in neurofibromatosis type 2 patients: clinical, radiological, and molecular features

Decision-making criteria for optimal management of meningiomas in neurofibromatosis type 2 (NF2) patients is hampered by lack of robust data, particularly long-term natural history. Seventy-four NF2 patients harboring 287 cranial meningiomas followed up for a mean period of 110.2 months were studied retrospectively. The median number of meningiomas per patient was 3. The mean maximum diameter of meningiomas at diagnosis was 14.3 mm, with a mean annual growth rate of 1.5 mm. Sixty-six percent of tumors showed no or minimal growth. In a subgroup of patients with 3D MRI, 7.3% of meningiomas (28% of patients) had a volumetric growth rate 20% or more per year. Twenty-five de novo meningiomas appeared during the follow-up (8.7%) and demonstrated a higher growth rate than other meningiomas (6.6 mm/year). Fifty-six meningiomas (23%) in 34 NF2 patients (45.9%) were operated on during the follow-up period. Among symptomatic resected meningiomas, grades II and III tumors were found in 29% and 6% of cases, respectively, with a remarkable intratumor histological heterogeneity. Single nucleotide polymorphism array analysis of 22 meningioma samples in 14 NF2 patients showed increasing chromosome instability with increasing grade, the most frequent losses being on 22q, 1p, 18q, and 6p. This study provides clues to improve tailored treatment of meningiomas: de novo and brain edema-associated meningiomas require active treatment. Future clinical trials in NF2 need to focus specifically on meningiomas as the primary endpoint and should include patients with meningiomas growing 20% or more per year in order to assess new treatments.

Single-Fraction Radiosurgery of Benign Intracranial Meningiomas

BACKGROUND:

Stereotactic radiosurgery (SRS) of benign intracranial meningiomas is an accepted management option for well-selected patients.

OBJECTIVE:

To analyze patients who had single-fraction SRS for benign intracranial meningiomas to determine factors associated with tumor control and neurologic complications.

METHODS:

Retrospective review was performed of 416 patients (304 women/112 men) who had single-fraction SRS for imaging defined (n = 252) or confirmed World Health Organization grade I (n = 164) meningiomas from 1990 to 2008. Excluded were patients with radiation-induced tumors, multiple meningiomas, neurofibromatosis type 2, and previous or concurrent radiotherapy. The majority of tumors (n = 337; 81%) involved the cranial base or tentorium. The median tumor volume was 7.3 cm3; the median tumor margin dose was 16 Gy. The median follow-up was 60 months.

RESULTS:

The disease-specific survival rate was 97% at 5 years and 94% at 10 years. The 5- and 10-year local tumor control rate was 96% and 89%, respectively. Male sex (hazard ratio [HR]: 2.5, P = .03), previous surgery (HR: 6.9, P = .002) and patients with tumors located in the parasagittal/falx/convexity regions (HR: 2.8, P = .02) were negative risk factors for local tumor control. In 45 patients (11%) permanent radiation-related complications developed at a median of 9 months after SRS. The 1- and 5-year radiation-related complication rate was 6% and 11%, respectively. Risk factors for permanent radiation-related complication rate were increasing tumor volume (HR: 1.05, P = .008) and patients with tumors of the parasagittal/falx/convexity regions (HR: 3.0, P = .005).

CONCLUSION:

Single-fraction SRS at the studied dose range provided a high rate of tumor control for patients with benign intracranial meningiomas. Patients with small volume, nonoperated cranial base or tentorial meningiomas had the best outcomes after single-fraction SRS.

Evolution and future of skull base surgery: the paradigm of skull base meningiomas

BACKGROUND

Skull base meningiomas represent the paradigm for the evolution of skull base surgery within the past 50 years into a distinct neurosurgical subspecialty.

METHODS

From 2005 to 2011, 117 patients with cranial base meningiomas underwent surgical resection. Extent of resection, histologic grade, complications, functional status, and recurrence-free and overall survival data are presented.

RESULTS

The summary rate of gross total resection was 53.0%. The surgical complication and mortality rates were 17.9% and 0.9%, respectively. Five-year recurrence-free survival was 88.0% for grade I meningiomas. A total of 90.3% of patients had a Karnofsky performance score ≥ 80 at last follow-up.

CONCLUSIONS

A large contemporary series of skull base meningiomas is presented. In addition, the evolution of surgical approaches to skull base meningiomas is reviewed, together with the current issues regarding radiation therapy, management of cavernous sinus tumor, oncologic management of atypical and malignant subtypes, molecular genetics, and future therapeutic options.

Intracranial hemangiopericytoma: clinical experience and treatment considerations in a modern series of 40 adult patients

INTRODUCTION

Intracranial hemangiopericytoma (HPC) is a malignant meningothelial tumor. Because of its rarity, few guidelines exist for optimal management.

METHODS

University of California at San Francisco patients managed for intracranial HPC were compiled into a single database based on a retrospective review of patient records. Univariate and multivariate regression was performed to determine factors that independently predicted treatment outcomes.

RESULTS

A total of 40 patients with intracranial HPC were treated from 1989 to 2010. Treatment and follow-up information was available for analysis on 35 patients. The median survival for all patients was 16.2 years after date of diagnosis, with 1-year, 5-year, and 10-year survival rates of 100%, 92%, and 68%, respectively. Nineteen patients (54%) had HPC recurrence. The median time until recurrence was 5 years, with 1-year, 5-year, and 10-year progression-free survival rates of 96%, 49%, and 28%, respectively. Seven patients (20%) developed extracranial metastasis. Tumor characteristics associated with earlier recurrence included size ≥6 cm (log-rank, P < .05) and nonskull base location (log-rank, P < .05). Strategies combining adjuvant radiation with tumor resection appeared to hinder tumor progression, but had no effect on overall survival or the development of metastasis. Greater extent of resection was associated with increased overall survival (log-rank, P < .05).

CONCLUSIONS

Adjuvant radiation may show promise in preventing tumor progression, but recurrence remains a common treatment outcome regardless of initial strategy. When safe and feasible, gross total resection should be pursued as an initial surgical strategy to maximize overall survival. The propensity of these tumors to metastasize makes detailed staging imaging necessary.

Anatomic location is a risk factor for atypical and malignant meningiomas

BACKGROUND

Grade II and III meningiomas have higher rates of tumor recurrence than grade I meningiomas after surgery and/or external irradiation. As the utility of noninvasive treatments for brain tumors increases, it is becoming increasingly important to assess the likelihood that a tumor is not benign before treatment initiation. Hence, the authors have reviewed a large series of their patients to determine risk factors for higher-grade pathology, with particular interest paid to tumor location.

METHODS

The authors reviewed 378 patients presenting at their institution from 2000 to 2007 with histologically confirmed meningioma, central pathology grading according to the World Health Organization 2000 guidelines, and tumor location confirmed with preoperative imaging. They performed univariate and multivariate logistic regression on potential risk factors for high-grade pathology.

RESULTS

Risk factors for grade II/III pathology included nonskull base location (2-fold) and male sex (2-fold). Patients with prior surgery had a 3-fold increased incidence of higher-grade meningiomas at presentation at the authors' center. The authors controlled for this referral bias by performing a multivariate regression, and analysis without patients receiving prior treatment. Ninety-seven percent of operations were performed for tumor size and clinical symptoms, whereas <3% were performed for interval growth or features concerning higher-grade pathology.

CONCLUSIONS

Nonskull-base meningiomas, male sex, and prior surgery impart increased risk for grade II or III pathology. This increased risk translates to probable poorer prognosis and increased likelihood of recurrence after treatment. Thus, it is prudent to take these specific variables into consideration in conjunction with the complete clinical presentation when advising patients regarding their prognosis.

Proteomic profiles differ between bone invasive and noninvasive benign meningiomas of fibrous and meningothelial subtype

Meningiomas of WHO grade I can usually be cured by surgical resection. However, some tumors may, despite their benign appearance, display invasive growth behavior. These tumors constitute a difficult clinical problem to handle. By histology alone, bone invasive meningiomas may be indistinguishable from their noninvasive counterparts. In this study we have examined the protein spectra in a series of meningiomas in search of protein expression patterns that may distinguish between bone invasive and noninvasive meningiomas. Tumor tissue from 13 patients with fibrous (6 invasive and 7 noninvasive) and 29 with meningothelial (10 invasive and 19 noninvasive) grade I meningiomas were analyzed by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI). Multivariate statistical methods were applied for data analyses. Comparing the protein spectra from invasive and noninvasive fibrous meningioma we found 22 peaks whose intensities were significantly different between the two groups (P < 0.001). Based on the expression pattern of these peaks we were able to perfectly separate the two entities (area under ROC curve = 1.0). In meningothelial meningioma the same comparison yielded six significantly differentially expressed peaks (P < 0.001), which to a large degree separated the invasive from noninvasive tissue (area under ROC curve = 0.873). By analyzing the protein spectra in benign meningiomas we could differentiate between invasive and noninvasive growth behavior in both fibrous and meningothelial meningiomas of grade I. A possibility for early identification of invasive grade I meningiomas may have a strong influence on the follow-up policy and the issue of early or late radiotherapy.

SPINAL MENINGIOMA SURGERY IN ELDERLY PATIENTS WITH PARAPLEGIA OR SEVERE PARAPARESIS

OBJECTIVE

In a multicenter study, 102 patients aged 70 years or older with paraplegia or severe paraparesis, and who underwent operation for spinal meningiomas, are presented to correlate surgery and outcome and to determine the most influential factors that affected this outcome.

METHODS

Five French neurosurgical centers participated in this retrospective study between 1990 and 2007. Pre- and postoperative neurological status were assessed using a grading system. All patients underwent operation, and neurological evaluations were conducted 3 months and 1 year after surgery. The median follow-up period was 49.5 months (range, 12–169 months). Data were analyzed using a multiple logistic regression model.

RESULTS

Twenty-six patients were paraplegic (Grade 4). Complete tumor removal was obtained in 93 patients. There was no surgical mortality, and morbidity was 9%. Three months after surgery, 7 of the patients were unchanged, 87 patients had improved, and 8 were not evaluated. One year after surgery, 7 of the 100 surviving patients were clinically unchanged and 93 had improved. Of those who had improved, 49 patients experienced complete recovery.

CONCLUSION

Advanced age did not seem to contraindicate surgery, even in patients with severe preoperative neurological deficits and/or an American Society of Anesthesiologists class of III. Quality of life can be improved in most cases.

World Health Organization Grades II and III meningiomas are rare in the cranial base and spine

OBJECTIVE

This study was undertaken to assess a possible relationship between the tumor location and the incidence of World Health Organization (WHO) Grades II and III meningiomas.

METHODS

A retrospective review of 794 consecutive patients who underwent meningioma resection between January 1991 and March 2004 was conducted. Among these, 47 patients (5.9%) with WHO Grade II meningiomas and 16 patients (2%) with Grade III meningiomas were further analyzed. Tumor location was assessed using preoperative magnetic resonance imaging scans and/or operative reports. Histological grading was done according to the WHO 2000 Classification scheme.

RESULTS

WHO Grade II tumors were found in eight out of 289 (2.8%) cranial base meningiomas and in zero spinal meningiomas, compared with 39 out of 429 (9.1%) non-cranial base meningiomas. Grade III histology was encountered in two (0.7%) cranial base tumors and in one out of 76 (1.3%) spinal tumors, compared with 13 (3%) non-cranial base tumors. The combined incidence of Grades II and III meningiomas was significantly lower in the cranial base (3.5%) and spinal (1.3%) locations compared with non-cranial base locations (12.1%) (P < 0.001).

CONCLUSION

WHO Grades II and III meningiomas occur far less frequently in the cranial base and spinal locations. Tumors arising from these locations may have different mechanisms of tumorigenesis and/or progression compared with meningiomas arising from other (non-cranial base) regions.

Falx meningiomas: surgical results and lessons learned from 68 cases

OBJECTIVE

The purpose of this study was to review the characteristics of falcine meningioma retrospectively and to identify the parameters associated with tumor recurrence.

METHODS

The analysis included; age, sex, extent of resection, and radiologic and pathologic findings. Falcine meningiomas were classified by location as anterior, middle, or posterior as described for parasagittal meningiomas.

RESULTS

Of the 795 meningioma patients treated between 1990 and 2004 at the authors' institution, 68 patients with meningiomas arising from the falx underwent craniotomies. There were 22 male and 46 female patients (1 : 2.1). Mean age was 55 years and ranged from 14 to 77 years. Locations of falcine meningioma were; the anterior third in 33 cases, middle in 20, and posterior in 15. Mean tumor volume was 42 cc and ranged from 4 to 140 cc. In 58 of the 68 patients tumors were totally removed. Additional surgery for recurrence was performed in 6 patients over 15 years. Of these 6 patients, only two patients underwent gross total tumor resection at first operation; the other four underwent subtotal tumor resection. Based on pathologic reports, the largest tumor subtype was transitional. There were four patients with a high grade tumor-three atypical and one anaplastic meningioma. Of the 68 patients, 59 achieved a good outcome (no neurological deficit or recurrence), six had temporary complications, two suffered new permanent postoperative deficits, and the remaining one died due to severe brain swelling despite postoperative intensive care. Extent of surgical resection was found to be significantly related to tumor recurrence.

CONCLUSION

Falcine meningioma accounted for 8.5% of intracranial meningiomas and the transitional meningioma was the most common subtype of falcine meningioma. Gross total resection of tumor was the single most important predictor of an improved surgical outcome.