Malignant potential of skull base versus non-skull base meningiomas: clinical series of 1,663 cases

Management Approaches in WHO Grade III Meningioma: A National Oncology Trainees' Collaborative for Healthcare Research (NOTCH) UK Multi-Centre Retrospective Study

AIMS

WHO Grade 3 (G3) meningiomas are rare tumours with limited data to guide management. This retrospective study documents UK management approaches across 14 centres over 11 years.

MATERIALS AND METHODS

Patients with WHO G3 meningioma between 01/01/2008 and 31/12/2018 were identified. Data were collected on demographics, management strategy, adjuvant radiotherapy, approach in recurrence setting and survival.

RESULTS

84 patients were identified. 21.4% transformed from lower-grade disease. 96.4% underwent primary surgical resection, with 20.8% having evidence of residual disease on their post-op MRI. 59.3% of patients underwent adjuvant radiotherapy (RT) following surgical resection. Overall median PFS and OS were 12.6 months and 28.2 months, respectively. Median OS in the group who underwent complete surgical resection was 34.9 months, compared to 27.5 months for those who had incomplete resection (HR 0.58, 95% CI 0.27-1.23, p = 0.15). Median OS was 33.1 months for those who underwent adjuvant RT and 14.0 months for those who did not (HR 0.48, 95% CI 0.27-0.84, p = 0.004). Median adjuvant RT dose delivered was 60Gy (range 12Gy-60Gy), 45.8% of adjuvant RT was delivered using IMRT. At disease relapse, 31% underwent salvage surgery and 29.3% underwent salvage RT. Of those treated with salvage RT, 64.7% were re-treats and all were treated with hypofractionated RT.

CONCLUSION

Surgery continues to be the preferred primary management strategy. Post-operative MRI within 48 hours is indicated to assess presence of residual disease and guide further surgical options. Adjuvant radiotherapy plays an important part of the management paradigm in these patients with the data supporting an attached survival advantage. Further surgery and re-irradiation is an option in the disease recurrence setting with radiosurgery frequently utilised in this context.

Anaplastic Transformation of Sphenoid Wing Meningioma With Orbital and Cavernous Sinus Invasion: Unveiling the Aggressive Nature

Primary tumors in the central nervous system, known as meningiomas, are frequently found and constitute a substantial proportion of tumor cases. Although generally benign, there are occasional cases where they might exhibit malignant characteristics. Anaplastic meningioma is a rare subtype of malignant meningiomas, representing only a small proportion of cases. We present the case of a 70-year-old female patient who presented to the Neurosurgery Clinic of University Hospital "Saint George" with clinical manifestations of monocular vision and blurry vision in the right eye for three months. On physical examination, unilateral ptosis and mydriasis were noted in the left eye. MRI revealed an extra-axial mass located supratentorial in the left temporopolar region affecting the wing of the left sphenoidal bone, invading the cavernous sinus, suppressing the left and right optic nerves, and involving the left orbit. Operative treatment was performed through a left pterional craniotomy and resection of the tumor mass by microsurgical technique. The subdural, epidural, and intraorbital mass were resected. Total removal of the tumor was not achievable and subtotal resection was performed. Pathology results showed that the tumor mass was anaplastic meningioma. Surgery-related complications were not observed. Postoperatively, the patient was mobilized on the day after intervention and the control CT scan showed no ischemic or hemorrhagic events. The patient experienced relief in her symptoms and was discharged on the fifth day. The patient underwent radiation therapy, resulting in the complete removal of the left tumor in the cavernous sinus. After six months, no tumor recurrence was found, and a long-term follow-up is planned to monitor for possible recurrence.

The Endoscopic Lateral Transorbital Approach for the Removal of Select Sphenoid Wing and Middle Fossa Meningiomas. Surgical Technique and Short-Term Outcomes

BACKGROUND AND OBJECTIVE

The endoscopic lateral transorbital approach (eLTOA) is a relatively new approach to the skull base that has only recently been applied in vivo in the management of complex skull base pathology. Most meningiomas removed with this approach have been in the spheno-orbital location. We present a series of select purely sphenoid wing and middle fossa meningiomas removed through eLTOA. The objective here was to describe the selection criteria and results of eLTOA for a subset of sphenoid wing and middle fossa meningiomas.

METHODS

This is a retrospective study based on a prospectively maintained database of consecutive cases of eLTOA operated on at our institution by the lead author. The cohort's clinical and radiographic characteristics and outcome are presented.

RESULTS

Five patients underwent eLTOA to remove 3 sphenoid wing and 2 middle fossa meningiomas. The mean tumor volume was 11.9 cm 3 . Gross total resection was achieved in all cases. There were no intraoperative complications. Postoperatively, there was one case of subretinal hemorrhage, which was corrected by open vitrectomy repair, and one case of cerebrospinal fluid leak, which resolved with lumbar drainage. Three patients presented with visual impairment, 1 improved, 1 remained stable, and 1 worsened, but returned to stable after vitrectomy repair. All patients have been free of disease at a median follow-up of 8.9 months.

CONCLUSION

eLTOA provides a direct minimal access corridor to certain well-selected sphenoid wing and middle fossa meningiomas. eLTOA minimizes brain retraction and provides a high rate of gross total resection. Meningiomas appropriately selected based on size, type, and location of dural attachment, and the eLTOA is a safe, rapid, and highly effective procedure with acceptable morbidity.

A novel BRAF::PTPRN2 fusion in meningioma: a case report

Gene fusion events have been linked to oncogenesis in many cancers. However, gene fusions in meningioma are understudied compared to somatic mutations, chromosomal gains/losses, and epigenetic changes. Fusions involving B-raf proto-oncogene, serine/threonine kinase (BRAF) are subtypes of oncogenic BRAF genetic abnormalities that have been reported in certain cases of brain tumors, such as pilocytic astrocytomas. However, BRAF fusions have not been recognized in meningioma. We present the case of an adult female presenting with episodic partial seizures characterized by déjà vu, confusion, and cognitive changes. Brain imaging revealed a cavernous sinus and sphenoid wing mass and she underwent resection. Histopathology revealed a World Health Organization (WHO) grade 1 meningioma. Genetic profiling with next generation sequencing and microarray analysis revealed an in-frame BRAF::PTPRN2 fusion affecting the BRAF kinase domain as well as chromothripsis of chromosome 7q resulting in multiple segmental gains and losses including amplifications of cyclin dependent kinase 6 (CDK6), tyrosine protein-kinase Met (MET), and smoothened (SMO). Elevated pERK staining in tumor cells provided evidence of activated mitogen-activated protein kinase (MAPK) signaling. This report raises the possibility that gene fusion events may be involved in meningioma pathogenesis and warrant further investigation.

Metastatic meningioma: a case series and systematic review

BACKGROUND

Meningiomas are the most common primary intracranial tumor. While the majority of meningiomas are benign, rarely they can metastasize extracranially. There is a need for a more comprehensive review of these patients to improve our understanding of this rare phenomenon and its prevalence globally. Here we describe our institution's experience of patients presenting with metastatic meningiomas. We further perform a systematic review of the existing literature to explore common features of this rare manifestation of meningioma and review the efficacy of current treatments.

METHODS

We performed a retrospective clinical review of all adult patients with metastatic meningioma managed at our institution over the past 20 years, identifying 6 patients. We then performed a systematic review of cases of metastatic meningioma in the literature ranging from the years 1886 to 2022. A descriptive analysis was then conducted on the available data from 1979 onward, focusing on the grade and location of the primary tumor as well as the latency period to, and location of, the metastasis.

RESULTS

In total, we analyzed 155 cases. Fifty-four percent of patients initially presented with a primary meningioma located in the convexity. The most common site of metastasis was the lung. Risk factors associated with a shorter time to metastasis were male sex and a high initial grade of the tumor. Regarding treatment, the addition of chemotherapy was the most common adjunct to the standard management of surgery and radiotherapy. Despite an exhaustive review we were unable to identify effective treatments. The majority of published cases came from centers situated in high-income countries (84%) while only 16% came from lower- and middle-income countries.

CONCLUSIONS

Metastatic meningiomas pose a pertinent, and likely underestimated, clinical challenge within modern neurosurgery. To optimize management, timely identification of these patients is important. More research is needed to explore the mechanisms underlying these tumors to better guide the development of effective screening and management protocols. However, screening of each meningioma patient is not feasible, and at the heart of this challenge is the inability to control the primary disease. Ultimately, a consensus is needed as to how to correctly screen for and manage these patients; genomic and epigenomic approaches could hold the answer to finding druggable targets.

Different clinical and cytogenetic features of primary skull base meningiomas and non-skull base meningiomas

PURPOSE

To investigate the different clinical and cytogenetic features of skull base meningiomas (SBMs) and non-SBMs (NSBMs).

METHODS

We conducted a retrospective study on a series of 316 patients with primary intracranial meningiomas. The t-test and the Chi-square test were used to analyze the differences between 194 SBMs and 122 NSBMs. The Cox analysis was used to determine prognostic factors for tumor recurrence.

RESULTS

Compared with NSBMs, on average, the age of patients with SBMs was about 2.88 years younger (p = 0.024); the duration of operation of SBMs was 2.73 h longer (p < 0.001); the duration of hospital stays of patients with SBMs was about 6.76 days longer (p < 0.001); the tumor volume was 7.69 cm³ smaller (p = 0.025); the intraoperative blood loss was 147.61ml more (p = 0.039); the total cost of SBMs was 1.39 times more (p < 0.001); the preoperative KPS, postoperative KPS, and follow-up KPS of patients with SBMs were all respectively lower (p < 0.001); Gross total resection was less achieved (p < 0.001). SBMs (average of 20.80 per sample) had a smaller total number of copy number variations (CNVs) than NSBMs (29.98 per sample) (p = 0.009). Extremely large CNVs (> 5 Mb) were more likely to present in NSBMs (p < 0.001). Cox analysis showed that subtotal resection (p = 0.002) and the total number of CNVs (p = 0.015) were independent risk factors for tumor recurrence.

CONCLUSIONS

The clinical and cytogenetic features of SBMs were different from NSBMs. Moreover, the degree of resection and the total number of whole-genome CNVs were independent prognostic factors for tumor recurrence.

Intracranial Meningiomas in Patients Aged ≥80 Years: Pathological Features and Surgical Problems

BACKGROUND

Patients aged >80 years frequently have intracranial meningiomas. In the present study, we have discussed the pathological features, comorbidities, and surgical complications for this age group from a surgical series and literature review.

METHODS

In the present study, we reviewed a surgical series of 354 intracranial meningiomas and compared the oldest age group (age, ≥80 years) of 17 patients with 73 patients aged 70-79 years and 264 patients aged <70 years. From a literature review, we selected 10 studies of meningiomas in patients aged ≥80 years. The analyzed factors included sex, meningioma location, World Health Organization grade, Ki-67 MIB1, progesterone receptor expression, comorbidities, American Society of Anesthesiologists class, Karnofsky performance scale score, postoperative complications, and death.

RESULTS

Patients aged ≥80 years had had higher rates of World Health Organization grade II meningioma, higher rates of Ki-67 expression of >4% and <20%, and progesterone receptor expression <15%. Of the postoperative complications, only neurological deficits and acute bronchopneumonia were significantly more frequent in patients aged ≥80 years. The incidence of intracerebral hematoma, lung embolism, acute heart ischemia, and death were not significantly different between the patients aged ≥80 years and those aged 70-79 years and <70 years.

CONCLUSIONS

Patients aged ≥80 years must be considered a true elderly group with higher rates of comorbidities. The very old age is not a limitation to surgery; however, careful patient selection is necessary. In addition, for the oldest age group, the surgical decision should not be delayed because of advancing age.

Systematic Review of Meningiomas Revealed by Spontaneous Intracranial Hemorrhage: Clinicopathological Features, Outcomes, and Rebleeding Rate

BACKGROUND

Meningiomas are rarely revealed by an intracranial hemorrhage (ICH). Rebleeding occurrence rate and time of onset are unknown. Here, we performed a systematic review of the literature of meningiomas revealed by ICH.

METHODS

We retrospectively collected all meningiomas revealed by spontaneous ICH published between January 1980 and December 2021. We reported clinicopathological features of meningiomas revealed by ICH. We also estimated rebleeding rate and time to onset.

RESULTS

Ninety-two studies met all inclusion criteria, led to a total of 120 cases. The mean age was 56.3 years, with 66 (55%) female. Seventy-nine (66%) cases were conscious before surgery, 20 (17%) were in coma, and 17 (14%) were unconscious after deterioration. The most frequent bleeding type was subdural hemorrhage (N = 49, 41%) followed by intraparenchymal hemorrhage (IPH) (N = 44, 37%), subarachnoid hemorrhage (SAH) (N = 22, 18%), and intraventricular hemorrhage (IVH) (N = 5, 4%). IPH and hindbrain/ventricular locations are associated with poor outcomes (P = 0.031 and < 0.001, respectively). Among the 19 patients who did not undergo surgical resection of the meningioma, 14 (74%) experienced rebleeding with a median occurrence of 120 days (interquartile, [90; -]). Rebleeding occurs earlier if the type of bleeding is SAH or IVH and for hindbrain location (both P < 0.01).

CONCLUSIONS

ICH is a rare presentation of meningiomas. Hindbrain and ventricular tumor location and IPH are associated with poor outcomes. Rebleeding rate is high and premature. It occurs earlier if the first bleeding was SAH or IVH and for hindbrain location.

De Novo Skull Base Atypical Meningioma: Incidence and Outcome

Objective  Atypical meningiomas are uncommon in skull base practice and present a management challenge. We aimed to review all de novo atypical skull base meningioma cases within a single unit to analyze presentation and outcome. Methods  A retrospective review of all patients undergoing surgery for intracranial meningioma identified consecutive cases of de novo atypical skull base meningioma. Electronic case records were analyzed for patient demographics, tumor location and size, extent of resection, and outcome. Tumor grading is based on the 2016 WHO criteria. Results  Eighteen patients with de novo atypical skull base meningiomas were identified. The most common tumor location was the sphenoid wing in 10 patients (56%). Gross total resection (GTR) was achieved in 13 patients (72%) and subtotal resection (STR) in 5 patients (28%). There was no tumor recurrence recorded in patients who had undergone GTR. Patients with tumors >6 cm were more likely to undergo a STR as opposed to a GTR ( p  < 0.01). Patients who had undergone a STR were more likely to have postoperative tumor progression and be referred for radiotherapy ( p  = 0.02 and <0.01, respectively). On multiple regression analysis, tumor size is the only significant factor correlating with overall survival ( p  = 0.048). Conclusion  The incidence of de novo atypical skull base meningioma is higher in our series than currently published data. Tumor size was a significant indicator for patient outcome and extent of resection. Those undergoing a STR were more likely to have tumor recurrence. Multicenter studies of skull base meningiomas with associated molecular genetics are needed to guide management.

Clinical Management of Supratentorial Non-Skull Base Meningiomas

Supratentorial non-skull base meningiomas are the most common primary central nervous system tumor subtype. An understanding of their pathophysiology, imaging characteristics, and clinical management options will prove of substantial value to the multi-disciplinary team which may be involved in their care. Extensive review of the broad literature on the topic is conducted. Narrowing the scope to meningiomas located in the supratentorial non-skull base anatomic location highlights nuances specific to this tumor subtype. Advances in our understanding of the natural history of the disease and how findings from both molecular pathology and neuroimaging have impacted our understanding are discussed. Clinical management and the rationale underlying specific approaches including observation, surgery, radiation, and investigational systemic therapies is covered in detail. Future directions for probable advances in the near and intermediate term are reviewed.

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.

Matched Paired Primary and Recurrent Meningiomas Points to Cell-Death Program Contributions to Genomic and Epigenomic Instability along Tumor Progression

Meningioma (MN) is an important cause of disability, and predictive tools for estimating the risk of recurrence are still scarce. The need for objective and cost-effective techniques addressed to this purpose is well known. In this study, we present methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) as a friendly method for deepening the understanding of the mechanisms underlying meningioma progression. A large follow-up allowed us to obtain 50 samples, which included the primary tumor of 20 patients in which half of them are suffering one recurrence and the other half are suffering more than one. We histologically characterized the samples and performed MS-MLPA assays validated by FISH to assess their copy number alterations (CNA) and epigenetic status. Interestingly, we determined the increase in tumor instability with higher values of CNA during the progression accompanied by an increase in epigenetic damage. We also found a loss of HIC1 and the hypermethylation of CDKN2B and PTEN as independent prognostic markers. Comparison between grade 1 and higher primary MN's self-evolution pointed to a central role of GSTP1 in the first stages of the disease. Finally, a high rate of alterations in genes that are related to apoptosis and autophagy, such as DAPK1, PARK2, BCL2, FHIT, or VHL, underlines an important influence on cell-death programs through different pathways.

Transcriptomic Profiling Revealed Lnc-GOLGA6A-1 as a Novel Prognostic Biomarker of Meningioma Recurrence

BACKGROUND

Meningioma is the most common primary central nervous system neoplasm, accounting for about a third of all brain tumors. Because their growth rates and prognosis cannot be accurately estimated, biomarkers that enable prediction of their biological behavior would be clinically beneficial.

OBJECTIVE

To identify coding and noncoding RNAs crucial in meningioma prognostication and pathogenesis.

METHODS

Total RNA was purified from formalin-fixed and paraffin-embedded tumor samples of 64 patients with meningioma with distinct clinical characteristics (16 recurrent, 30 nonrecurrent with follow-up of >5 years, and 18 with follow-up of <5 years without recurrence). Transcriptomic sequencing was performed using the HiSeq 2500 platform (Illumina), and biological and functional differences between meningiomas of different types were evaluated by analyzing differentially expression of messenger RNA (mRNA) and long noncoding RNA (IncRNA). The prognostic value of 11 differentially expressed RNAs was then validated in an independent cohort of 90 patients using reverse transcription quantitative (real-time) polymerase chain reaction.

RESULTS

In total, 69 mRNAs and 108 lncRNAs exhibited significant differential expression between recurrent and nonrecurrent meningiomas. Differential expression was also observed with respect to sex (12 mRNAs and 59 lncRNAs), World Health Organization grade (58 mRNAs and 98 lncRNAs), and tumor histogenesis (79 mRNAs and 76 lncRNAs). Lnc-GOLGA6A-1, ISLR2, and AMH showed high prognostic power for predicting meningioma recurrence, while lnc-GOLGA6A-1 was the most significant factor for recurrence risk estimation (1/hazard ratio = 1.31; P = .002).

CONCLUSION

Transcriptomic sequencing revealed specific gene expression signatures of various clinical subtypes of meningioma. Expression of the lnc-GOLGA61-1 transcript was found to be the most reliable predictor of meningioma recurrence.

The Long and Winding Road: An Overview of the Immunological Landscape of Intracranial Meningiomas

Simple Summary

The tumor microenvironment represents the essential basis for characterizing oncological cells and supporting their growth. Along with genomic sequencing, the study of the tumor microenvironment represents a big step forward in oncological research and in the customization of treatments. Compared to gliomas, for which research has discovered greater results, the correlation between the microenvironment and tumor phenotype, and consequent prognostic implications, are still incompletely understood for intracranial meningioma. Recently, studies about the immunogenetic landscape of meningiomas have been promoted, and it is now clear that understanding the multifactorial pathogenesis of meningioma and its correlation with other specific signs (i.e., PTBE) could lead to the development of new targeted therapies, and significantly affect meningioma patients’ prognosis.

Abstract

The role of immunotherapy is gaining ever-increasing interest in the neuro-oncological field, and this is also expanding to the management of intracranial meningioma. Meningiomas are still the most common primary adult tumor of the CNS, and even though surgery and/or radiotherapy still represent cornerstones of their treatment, recent findings strongly support the potential role of specific immune infiltrate cells, their features and genomics, for the application of personalized treatments and prognostic implications. According to the PRISMA guidelines, systematic research in the most updated platform was performed in order to provide a descriptive and complete overview about the characteristics, role and potential implications of immunology in meningioma tumors. Seventy articles were included and analyzed in the present paper. The meningioma microenvironment reveals complex immune tumor-immune cells interactions that may definitely influence tumor progression, as well as offering unexpected opportunities for treatment.

Clinical and pathological impact of an optimal assessment of brain invasion for grade 2 meningioma diagnosis: lessons from a series of 291 cases

Brain invasion has not been recognized as a standalone criterion for atypical meningioma by the WHO classification until 2016. Since the 2007 edition suggested that meningiomas harboring brain invasion could be classified as grade 2, brain invasion study was progressively strengthened in our center, based on a strong collaboration between neurosurgeons and neuropathologists regarding sample orientation and examination. Practice changes were considered homogeneous enough in 2011. The aim of the present study was to evaluate the impact of gross practice change on the clinical and pathological characteristics of intracranial meningiomas classified as grade 2.The characteristics of consecutive patients with a grade 2 meningioma surgically managed before (1998-2005, n = 125, group A) and after (2011-2014, n = 166, group B) practices changed were retrospectively reviewed.Sociodemographical and clinical parameters were comparable in groups A and B, and the median age was 62 years in both groups (p = 0.18). The 5-year recurrence rates (23.2% vs 29.5%, p = 0.23) were similar. In group A, brain invasion was present in 48/125 (38.4%) cases and was more frequent than in group B (14/166, 8.4%, p < 0.001). In group A, 33 (26.4%) meningiomas were classified as grade 2 solely based on brain invasion (group A_SBI), and 92 harbored other grade 2 criteria (group A_OCA). Group A_SBI meningiomas had a similar median progression-free survival compared to groups A_OCA (68 vs 80 months, p = 0.24) and to A_OCA and B pooled together (n = 258, 68 vs 90 months, p = 0.42).An accurate assessment of brain invasion is mandatory as brain invasion is a strong predictor of meningioma progression.

Inflammatory Tumor Microenvironment in Cranial Meningiomas: Clinical Implications and Intraindividual Reproducibility

The MIB-1 index was demonstrated to be significantly correlated to meningioma recurrence. However, to date, the relationship of the intraindividual course of the MIB-1 index and the growth fraction, respectively, to clinical tumor recurrence has not been demonstrated in cranial WHO grade 1 and 2 meningiomas. In the present paper, we compare the MIB-1 indices of 16 solely surgically treated primary meningiomas and their recurrent tumors regarding the course of the MIB-1 indices, time to recurrence, reproducibility and factors influencing the intraindividual MIB-1 indices. Regression analyses revealed (1) a strong intra-lab reproducibility (r = 0.88) of the MIB-1 index at the second versus the first operation, corresponding to a constant intrinsic growth activity of an individual meningioma, (2) a significant inverse correlation of both primary (r = −0.51) and secondary (r = −0.70) MIB-1 indices to time to recurrence, and (3) male sex, low plasma fibrinogen and diffuse CD68⁺ macrophage infiltrates contribute to an increase in the MIB-1 index. A strong intraindividual reproducibility of the MIB-1 index and a direct relationship of the MIB-1 index to the time to recurrence were observed. Individual MIB-1 indices might be used for tailored follow-up imaging intervals. Further research on the role of macrophages and inflammatory burden in the regrowth potential of meningiomas are needed.

Proliferative Potential, and Inflammatory Tumor Microenvironment in Meningioma Correlate with Neurological Function at Presentation and Anatomical Location-From Convexity to Skull Base and Spine

Simple Summary

The World Health Organization (WHO) classification grades meningiomas exclusively due to their histopathological features. Meningiomas are predominantly benign intracranial entities, and surgical resection represents the therapy of choice. However, risk of progression and tailored scheduling of follow-up appointments are significantly influenced by various items, such as immunohistochemistry (e.g., MIB-1 index). Emerging evidence focuses attention on the anatomic location of meningiomas, especially regarding the differentiation between skull base and non-skull base meningiomas. In the present study, we therefore investigated demographic, histopathological, and laboratory variables regarding their association with the anatomic location. We found that spinal meningiomas have a significantly lower proliferative activity, less density of macrophage infiltrates, and a longer time to tumor progression. Moreover, increased MIB-1 indices are significantly associated with location-specific baseline symptoms (e.g., convexity: seizure burden, medial skull base: decreased vision, spinal: ambulatory ability). Therefore, anatomic location might be considered as a future subclassification in the grading of the prognosis of meningiomas.

Abstract

Emerging evidence emphasizes the prognostic importance of meningioma location. The present investigation evaluates whether progression-free survival (PFS), proliferative potential, World Health Organization (WHO) grades, and inflammatory burden differ between anatomical locations (skull base, non-skull base, and spinal) meningiomas. Five-hundred-forty-one patients underwent Simpson grade I or II resection for WHO grade 1 or 2 meningiomas. Univariable analysis revealed that spinal meningioma patients are significantly older, had a worse baseline Karnofsky Performance Status (KPS), higher acute-phase protein levels, lower incidence of WHO grade 2, lower mitotic counts, lower MIB-1 index, and less CD68⁺ macrophage infiltrates. Multivariable analysis identified WHO grade 2 (OR: 2.1, 95% CI: 1.1–3.7, p = 0.02) and cranial location (OR: 3.0, 95% CI: 1.8–4.9, p = 0.001) as independent predictors of diffuse CD68⁺ macrophage infiltrates. The mean PFS in cranial meningiomas was 115.9 months (95% CI: 107.5–124.3), compared to 162.2 months (95% CI: 150.5–174.0; log-rank test: p = 0.02) in spinal meningiomas. Multivariable Cox regression analysis revealed cranial location as an independent predictor (HR: 4.7, 95% CI: 1.0–21.3, p = 0.04) of shortened PFS. Increased MIB-1 indices ≥5% were significantly associated with location-specific deficits at presentation, such as decreased vision and seizure burden. Spinal meningiomas have a significantly longer PFS time and differ from the cranial meningiomas regarding MIB-1 index and density of tumor-associated macrophages.

Skull Base Meningiomas: Is Surgical Resection Enough? Outcome Evaluation and Prognostic Factors Analysis in a Single-Center Cohort

BACKGROUND

 Surgical resection represents the mainstay of treatment in skull base meningiomas (SBMs). Considering the high recurrence rate reported, an adjuvant radiation therapy (RT) treatment should be considered. The aim of this study was to evaluate the progression-free survival (PFS), overall survival (OS), and prognostic factors conditioning outcome.

METHODS

 Patients receiving surgical resection for grade I SBMs were included. The extent of resection (EOR) was dichotomized as gross total resection (GTR) and subtotal resection (STR). RT was administered only in patients receiving STR. Clinical outcome was evaluated by brain magnetic resonance imaging (MRI) performed every 6 months for the first year and yearly thereafter.

RESULTS

 From January 2000 to December 2015, 123 patients were treated. The majority were females (70.7%), with a Karnofsky Performance Score (KPS) ≥80 (95%), and symptoms at diagnosis (91%). GTR was performed in 30% of cases and STR in 70%. RT was performed in 18 (20.9%) patients at diagnosis and in 29 (33.7%) patients at progression. Improvement or stability of neurologic status was obtained in 78.9% of patients. The median follow-up time was 91 months (range: 40-230 months). Local recurrence occurred in 34 (27.6%) patients at a median time of 45 months (range: 6-214 months). The median, 2-, 5-, and 10-year PFS were 193 months, 89.3, 81.8, and 72.5%, respectively. On univariate and multivariate analyses, factors impacting on PFS were EOR, tumor location, neurologic postoperative status, and adjuvant RT in STR.

CONCLUSIONS

 A safe surgical resection followed by RT adjuvant treatment could represent the better choice to obtain local control maintaining neurologic integrity. Our data underlined the value of adjuvant RT in incompletely resected meningiomas.

AKT1E17K -mutated meningioma cell lines respond to treatment with the AKT inhibitor AZD5363

AIMS

Meningiomas are the most frequent primary brain tumours. Recently, knowledge about the molecular drivers underlying aggressive meningiomas has been expanded. A hotspot mutation in the AKT1 gene (AKT1^E17K ), which is found in meningiomas at the convexity and especially at the skull base, has been associated with earlier tumour recurrence.

METHODS

Here, we analysed the effects of the AKT1^E17K mutation and treatment response to the Akt inhibitor AZD5363 in transgenic meningioma cell clones and mouse xenografts modelling convexity or skull base meningiomas.

RESULTS

We show that the AKT^E17K mutation significantly enhances meningioma cell proliferation and colony size in vitro, resulting in significantly shortened survival times of mice carrying convexity or skull base AKT1^E17K xenografts. Treatment of mutant cells or xenografts (150 mg/kg/d) with AZD5363 revealed a significant decrease in cell proliferation and colony size and a prolongation of mouse survival. Western blots revealed activation of AKT1 kinase (phosphorylation at Ser273 and Thr308) by the E17K mutation in human meningioma samples and in our in vitro and in vivo models.

CONCLUSIONS

Our data suggest that AKT1^E17K mutated meningiomas are a promising selective target for AZD5363.

A Clinical Semantic and Radiomics Nomogram for Predicting Brain Invasion in WHO Grade II Meningioma Based on Tumor and Tumor-to-Brain Interface Features

Background

Brain invasion in meningioma has independent associations with increased risks of tumor progression, lesion recurrence, and poor prognosis. Therefore, this study aimed to construct a model for predicting brain invasion in WHO grade II meningioma by using preoperative MRI.

Methods

One hundred seventy-three patients with brain invasion and 111 patients without brain invasion were included. Three mainstream features, namely, traditional semantic features and radiomics features from tumor and tumor-to-brain interface regions, were acquired. Predictive models correspondingly constructed on each feature set or joint feature set were constructed.

Results

Traditional semantic findings, e.g., peritumoral edema and other four features, had comparable performance in predicting brain invasion with each radiomics feature set. By taking advantage of semantic features and radiomics features from tumoral and tumor-to-brain interface regions, an integrated nomogram that quantifies the risk factor of each selected feature was constructed and had the best performance in predicting brain invasion (area under the curve values were 0.905 in the training set and 0.895 in the test set).

Conclusions

This study provided a clinically available and promising approach to predict brain invasion in WHO grade II meningiomas by using preoperative MRI.

Diagnostic nomogram model for predicting preoperative pathological grade of meningioma

Background

Meningioma is the most common primary tumor of the central nervous system. Preoperative diagnosis of high-grade meningioma is helpful for the selection of treatment options. The aim of our study is to establish a diagnostic nomogram model for preoperative prediction of the pathological grade of meningioma.

Methods

The predictive model was established from a cohort of 215 clinicopathologically confirmed meningioma between January 2012 and December 2017. Radiomic features were collected from preoperative magnetic resonance imaging (MRI) and computed tomography of patients with meningioma. The least absolute shrinkage and selection operator (LASSO) regression model was used for data dimension reduction and feature selection. Multivariate logistic regression was used to build a predictive model and presented as a nomogram. The performance of the nomogram was assessed with respect to its calibration, discrimination, and clinical usefulness. Internal validation was evaluated using bootstrapping validation.

Results

High-grade meningioma was observed in 47 patients (22%). The predictors included in the nomogram were tumor-brain interface, bone invasion, and tumor location. The final diagnostic model exhibited good calibration and discrimination with a C-index of 0.874 (95% confidence interval: 0.818–0.929) and a higher C-index of 0.868 in internal validation. Decision curve analysis (DCA) indicated that the nomogram is very useful in clinical practice.

Conclusions

This study provides a nomogram model with tumor-brain interface, bone invasion, and tumor location that can effectively predict the preoperative pathological grading of patients with meningioma and thus help clinicians provide more reasonable treatment strategies for meningioma patients.

Treatment and follow-up results of WHO grade II meningiomas

Meningiomas are the most common primary intracranial tumors. They have three pathologic grades. Surgical resection aiming Simpson I resection is the standard treatment for meningiomas. Radiotherapy and Gamma Knife radiosurgery are the main adjuvant and salvage treatments. Chemotherapy has limited use. Grade II, and III meningiomas have a higher recurrence rate, and adjuvant radiotherapy is usually the standard treatment for grade III meningiomas but there is not a consensus regarding grade II meningiomas. In this paper, we analyzed our meningioma series of 1401 patients and presented the treatment and follow-up results of 170 grade II meningioma cases. The median follow-up of grade II meningiomas was 61 (range = 1-231) months. The mean age of patients was 52.5 ± 15.0 years, 102 of them were female and 68 were male (female/male ratio = 1.5). The median progression-free survival (PFS) of them was 109 months, and the cumulative overall survival (OS) rate was 85% at 10 years. Meningiomas with gross total resection, non-skull base meningiomas, and primary grade II meningiomas had longer PFS with statistical significance, while non-skull base meningiomas, younger group of patients, and primary grade II meningiomas had longer OS with a statistical significance.

Neurosurgical follow-up and treatment of a series of 26 WHO grade III meningiomas

Meningiomas are the most common primary intracranial tumors. They have three pathologic grades. Surgical resection aiming Simpson I resection is the standard treatment for meningiomas. Radiotherapy and Gamma Knife radiosurgery are the main adjuvant and salvage treatments. Chemotherapy has limited use. Grade II, and III meningiomas have a higher recurrence rate, and adjuvant radiotherapy is usually the standard treatment for grade III meningiomas. In this paper, we analyzed our meningioma series of 1401 patients and presented the treatment and follow-up results of 26 grade III meningioma cases. Median follow-up of grade III meningiomas was 40.5 (range, 1-154) months. The mean age of patients was 51.7 ± 15.7 years; 12 of them were female and 14 were male (female/male ratio = 0.9). The median progression-free survival (PFS) of them was 22 months, and overall survival (OS) was 62 months. Meningiomas with gross total resection (GTR), non-skull base meningiomas, and primary grade III meningiomas had longer PFS, while meningiomas with GTR, non-skull base meningiomas, and primary meningiomas had longer OS with a statistical significance.

Risk Factors for High-Grade Meningioma in Brain and Spine: Systematic Review and Meta-analysis

BACKGROUND

Histologic grade has important implications for the management in meningioma. It is important to understand the risk of high-grade meningioma (grades II and III). In this article, we systematically reviewed the histologic grade of meningioma depending on the location and sex and its relationship with recurrence.

METHODS

The PubMed and Embase databases were systematically searched until February 4, 2020. We included studies that were not restricted to specific anatomic locations, histologic grade, or the sizes of the tumors. The proportion of high-grade meningiomas depending on the location and sex and the odds ratio (OR) of recurrence were pooled using a random-effects model.

RESULTS

Outcome data were analyzed for 20,336 tumors from 34 studies. We found different proportions of high-grade meningiomas in the brain (12.8%) (95% confidence interval [CI], 10.5%-15.1%) versus the spine (2.4%) (95% CI, 1.0%-3.7%) (P < 0.01). Skull base meningiomas (8.7%) (95% CI, 5.8%-11.6%) had a lower proportion of high-grade meningiomas than non-skull base meningiomas (16.5%) (95% CI, 11.9%-21.1%) (P < 0.01). In addition, high-grade meningiomas were more likely to occur in male patients (18.0%) (95% CI, 10.1%-25.9%) than female patients (7.0%) (95% CI, 3.5%-10.6%) (P = 0.01). Higher rates of recurrence (OR = 13.83) were confirmed for high-grade meningiomas than grade I meningiomas (95% CI, 4.10-46.65) (P < 0.01).

CONCLUSIONS

This meta-analysis found that intracranial, nonskull base, and male sex are risk factors for high-grade meningioma, and high-grade meningioma had a much higher recurrence rate as compared with grade I meningioma.

Associations of pathological diagnosis and genetic abnormalities in meningiomas with the embryological origins of the meninges

Certain driver mutations and pathological diagnoses are associated with the anatomical site of meningioma, based on which the meninges have different embryological origins. We hypothesized that mutations and pathological diagnoses of meningiomas are associated with different embryological origins. We comprehensively evaluated associations among tumor location, pathological diagnosis (histological type), and genetic alterations including AKT1, KLF4, SMO, POLR2A, and NF2 mutations and 22q deletion in 269 meningioma cases. Based on the embryological origin of meninges, the tumor locations were as follows: neural crest, paraxial mesodermal, and dorsal mesodermal origins. Tumors originating from the dura of certain embryologic origin displayed a significantly different pathological diagnoses and genetic abnormality ratio. For instance, driver genetic mutations with AKT1, KLF4, SMO, and POLR2A, were significantly associated with the paraxial mesodermal origin (p = 1.7 × 10⁻¹⁰). However, meningiomas with NF2-associated mutations were significantly associated with neural crest origin (p = 3.9 × 10^–12). On analysis of recurrence, no difference was observed in embryological origin. However, POLR2A mutation was a risk factor for the tumor recurrence (p = 1.7 × 10⁻², Hazard Ratio 4.08, 95% Confidence Interval 1.28–13.0). Assessment of the embryological origin of the meninges may provide novel insights into the pathomechanism of meningiomas.

World Health Organization Grade III Meningiomas: A Retrospective Study at an Academic Medical Center

BACKGROUND

Meningiomas are the most common primary brain tumors and are generally considered benign. However, a rare subgroup of meningiomas, classified as World Health Organization (WHO) grade III meningiomas, can show extremely aggressive behavior and high rates of recurrence. Despite ongoing research, data on the clinical outcome of this subgroup of meningiomas are still limited.

METHODS

Medical records of patients with WHO grade III meningiomas diagnosed between 2000 and 2018 at the Coimbra University Hospital Center were retrospectively reviewed and several variables of interest and their relation to patients' survival were analyzed.

RESULTS

Of the 26 patients included in the final analysis, 23 had anaplastic meningiomas, 2 had papillary meningiomas, and 1 had a rhabdoid meningioma. Median overall survival and median progression-free survival were 2.45 and 1.22 years, respectively. Overall survival at 1, 2 and 5 years was 73%, 57%, and 35%, respectively. Adjuvant radiotherapy correlated with improved survival for subtotally resected meningiomas but not for gross totally resected meningiomas. There was a trend toward improved overall survival with gross total resection versus subtotal resection, but this difference failed to reach statistical significance.

CONCLUSIONS

This study provides insight into the clinical outcomes of WHO grade III meningiomas and suggests that adjuvant radiotherapy may not be beneficial for patients who underwent gross total resection. This rare subset of meningiomas still portends a devastating prognosis and the impact of extent of resection and adjuvant therapies in these patients needs further clarification.

Malignant meningioma with jugular vein invasion and carotid artery extension: A case report and review of the literature

BACKGROUND

Grade II and III meningiomas [World Health Organization (WHO) classification] rarely have extracranial metastases via the blood circulation; however, we experienced a case with a metaplastic atypical meningioma and local de-differentiation that metastasized to the jugular vein, carotid artery and subclavian artery at the cervicothoracic junction. Such cases have seldom been reported before.

CASE SUMMARY

The patient was a 30-year-old man who developed right neck masses with dysphagia, labored breathing, dizziness, and occasional earaches. Eight months earlier the patient was diagnosed with a right parietal lobe neoplasm and hemorrhage at a local hospital due to the sudden onset of headaches and left limb weakness, and the post-operative pathology was a metaplastic atypical meningioma (WHO grade II) with local de-differentiation (WHO III). Magnetic resonance imaging revealed a calcified mass at the root of the neck on the right and a large cystic mass in the right parapharyngeal space. Head and neck angiography showed that the right common carotid artery was compressed and completely occluded, and the jugular vein was enveloped by the tumor and occluded. A balloon occlusion test showed no perfusion in the right common carotid artery. Tumor resection, carotid artery ligation, and subclavian artery reconstruction were performed. The tumor was a malignant meningioma. Post-operatively, the patient had Horner's syndrome and hoarseness.

CONCLUSION

This case highlights the importance of the link between a large cervical mass and a primary intracranial tumor. Malignant meningioma should not be considered merely as an intracranial metastasis spread through cerebrospinal fluid, it can also be transferred through the circulation to the parapharyngeal space and the cervical great vessels.

Malignant transformation of WHO grade I meningiomas after surgery or radiosurgery: systematic review and meta-analysis of observational studies

Background

The incidence and clinical features of the malignant transformation of benign meningiomas are poorly understood. This study examined the risk of the malignant transformation of benign meningiomas after surgery or stereotactic radiosurgery.

Methods

We systematically reviewed studies published between 1979 and 2019 using PubMed, Scopus, and other sources. We analyzed pooled data according to the PRISMA guideline to clarify the incidence rate of malignant transformation (IMT) and factors affecting malignant transformation in surgically or radiosurgically treated benign meningiomas.

Results

IMT was 2.98/1000 patient-years (95% confidence interval [CI] = 1.9–4.3) in 13 studies in a single-arm meta-analysis. Although the evidence level of the included studies was low, the heterogeneity of the incidence was mostly explained by the tumor location. In meta-regression analysis, skull base tumors had a significantly lower IMT than non-skull base tumors, but no gender association was observed. IMT after radiosurgery in 9 studies was 0.50/1000 person-years (95% CI = 0.02–1.38). However, a higher proportion of skull base tumors, lower proportion of males, and lower salvage surgery rate were observed in the radiosurgery group than in the surgery group. The median time to malignant change was 5 years (interquartile range = 2.5–8.2), and the median survival after malignant transformation was 4.7 years (95% CI = 3.7–8) in individual case data.

Conclusion

IMT of benign meningioma was significantly affected by the tumor location. Radiosurgery did not appear to increase IMT, but exact comparisons were difficult because of differences in study populations.

Histological transformation in recurrent WHO grade I meningiomas

Atypical or malignant transformation (AT/MT) has been described in WHO grade I meningiomas. Our aim was to identify predictive factors of AT/MT at recurrence. A total of N = 15 WHO grade increases were observed in N = 13 patients (0.96% of the study population, risk of transformation of 0.12% per patient-year follow-up). Patients with and without progression at recurrence were similar regarding age, gender distribution, skull-base location, bone infiltration, and Simpson grades. Recurrence-free survival was lower in patients with transformation (5 ± 4.06 years versus 7.3 ± 5.4 years; p = 0.03). Among patient age, gender, skull base location, extent of resection or post-operative RT, no predictor of AT/MT was identified, despite a follow-up of 10,524 patient-years. The annual risk of transformation of WHO grade I meningiomas was 0.12% per patient-year follow-up. Despite the important number of patients included and their extended follow-up, we did not identify any risk factor for transformation. A total of 1,352 patients with surgically managed WHO grade I meningioma from a mixed retro-and prospective database with mean follow-up of 9.2 years ± 5.7 years (0.3–20.9 years) were reviewed. Recurring tumors at the site of initial surgery were considered as recurrence.

Multi-parametric qualitative and quantitative MRI assessment as predictor of histological grading in previously treated meningiomas

PURPOSE

Meningiomas are mainly benign tumors, though a considerable proportion shows aggressive behaviors histologically consistent with atypia/anaplasia. Histopathological grading is usually assessed through invasive procedures, which is not always feasible due to the inaccessibility of the lesion or to treatment contraindications. Therefore, we propose a multi-parametric MRI assessment as a predictor of meningioma histopathological grading.

METHODS

Seventy-three patients with 74 histologically proven and previously treated meningiomas were retrospectively enrolled (42 WHO I, 24 WHO II, 8 WHO III) and studied with MRI including T2 TSE, FLAIR, Gradient Echo, DWI, and pre- and post-contrast T1 sequences. Lesion masks were segmented on post-contrast T1 sequences and rigidly registered to ADC maps to extract quantitative parameters from conventional DWI and intravoxel incoherent motion model assessing tumor perfusion. Two expert neuroradiologists assessed morphological features of meningiomas with semi-quantitative scores.

RESULTS

Univariate analysis showed different distributions (p < 0.05) of quantitative diffusion parameters (Wilcoxon rank-sum test) and morphological features (Pearson's chi-square; Fisher's exact test) among meningiomas grouped in low-grade (WHO I) and higher grade forms (WHO II/III); the only exception consisted of the tumor-brain interface. A multivariate logistic regression, combining all parameters showing statistical significance in the univariate analysis, allowed discrimination between the groups of meningiomas with high sensitivity (0.968) and specificity (0.925). Heterogeneous contrast enhancement and low ADC were the best independent predictors of atypia and anaplasia.

CONCLUSION

Our multi-parametric MRI assessment showed high sensitivity and specificity in predicting histological grading of meningiomas. Such an assessment may be clinically useful in characterizing lesions without histological diagnosis. Key points • When surgery and biopsy are not feasible, parameters obtained from both conventional and diffusion-weighted MRI can predict atypia and anaplasia in meningiomas with high sensitivity and specificity. • Low ADC values and heterogeneous contrast enhancement are the best predictors of higher grade meningioma.

Management of incidental anterior skull base large and giant meningiomas in elderly patients

INTRODUCTION

The incidence of meningiomas among the elderly is considered to be high, and are at increased risk of severe morbidity and mortality following surgery due to their aging physiology and unexpected comorbidities. This study aimed to evaluate the optimal management strategies of meningiomas in elderly patients.

METHODS

We retrospectively analyzed 150 patients with incidental large (≥ 3 cm) and giant (≥ 6 cm) anterior skull base meningiomas from 2009 to 2018. These patients were divided into elderly group (≥ 65 years, n = 70) and younger group (< 65 years, n = 80). Information of patients with regard to their medical records, operative details, relevant imaging, and follow-up data were obtained from their respective electronic medical records.

RESULTS

The elderly patients had significantly longer length of hospital stay (15.9 ± 3.5) compared to younger patients (13.6 ± 3.6, P < 0.001). Karnofsky Performance Scale (KPS) at discharge was significantly lower in elderly group when compared to younger group (P = 0.04). However, the KPS at 1-year after surgery was similar between the two groups. In addition, there was no significant difference in the incidence of surgical complications between the two groups. Multivariate regression analysis of postoperative complications revealed blood loss ≥ 800 mL (P = 0.007) and BMI (< 18.5 or ≥ 24, P < 0.001) as risk factors, rather than age.

CONCLUSIONS

Surgical resection in elderly patients with incidental anterior skull base large and giant meningiomas is considered to be a safe and effective therapeutic option owing to acceptable mortality, postoperative complications and postoperative clinical outcomes.

Multicentric and diffuse recurrences of meningiomas

Background: Meningiomas recur with a rate of 10-32% at 10 years. Several features influence the risk of recurrence.Objective: To define the pathological and surgical features at risk of multicentric-diffuse versus local-peripheral recurrence.Methods: Thirty-three patients operated on for intracranial meningiomas who experienced multicentric-diffuse recurrence were retrospectively analyzed. The data of these patients were compared to those of 50 patients who experienced local-peripheral recurrence. The analyzed factors included age and sex, tumor location and shape, brain-tumor interface, entity of resection, WHO grade, Ki67 MIB1, progesterone receptor (PR) expression, number of reoperations, progression of WHO grade, and outcome.Results: Meningiomas which recurred in multicentric-diffuse pattern showed at initial surgery a significantly higher rate of flat-shaped tumors (p = .0008) and of cases with Ki67 Li ≥ 4% (p = .037) than those which recurred in localized-peripheral pattern, whereas other factors did not significantly differ. Among patients with multicentric-diffuse recurrences, 25 underwent one to three reoperations; 17 among them (66%) are alive with local tumor control or slow progression 2-25 years after the initial surgery versus only 2 out of 8 who did not undergo surgery.Conclusions: Flat-shaped meningiomas and those with Ki67 Li ≥ 4% are at higher risk of multicentric-diffuse recurrence. Multiple reoperations over a period of several years may obtain rather long survivals in selected patients with prevalent intradural, not anaplastic tumors and not too extensive dural infiltration.

KLF4K409Q-mutated meningiomas show enhanced hypoxia signaling and respond to mTORC1 inhibitor treatment

Meningioma represents the most common primary brain tumor in adults. Recently several non-NF2 mutations in meningioma have been identified and correlated with certain pathological subtypes, locations and clinical observations. Alterations of cellular pathways due to these mutations, however, have largely remained elusive. Here we report that the Krueppel like factor 4 (KLF4)-K409Q mutation in skull base meningiomas triggers a distinct tumor phenotype. Transcriptomic analysis of 17 meningioma samples revealed that KLF4^K409Q mutated tumors harbor an upregulation of hypoxia dependent pathways. Detailed in vitro investigation further showed that the KLF4^K409Q mutation induces HIF-1α through the reduction of prolyl hydroxylase activity and causes an upregulation of downstream HIF-1α targets. Finally, we demonstrate that KLF4^K409Q mutated tumors are susceptible to mTOR inhibition by Temsirolimus. Taken together, our data link the KLF4^K409Q mediated upregulation of HIF pathways to the clinical and biological characteristics of these skull base meningiomas possibly opening new therapeutic avenues for this distinct meningioma subtype.

Sphenoid Wing Meningioma Presenting as Sudden Sensorineural Hearing Loss: A Case Report and Literature Review

Sphenoid wing meningiomas are tumors that typically present with vision deterioration and neurological changes due to their proximity to the sella, cavernous sinus, and other vital structures. Some unusual symptoms have also been described in the literature, such as cognitive dysfunction, parkinsonism, and intracerebral hemorrhage. In this report, we detail another unusual case of sphenoid wing meningioma in a 63-year-old female who presented with left sudden sensorineural hearing loss. A brief review of the literature is also included.

The Loss of 1p as a Reliable Marker of Progression in a Child with Aggressive Meningioma: A 16-Year Follow-Up Case Report

BACKGROUND

Here, we present the case of a 32-year-old female with a progressing history of meningioma for 16 years starting with an ethmoidal lesion in 2002. The initial tumor specimen of this patient showed a deletion of the short arm of chromosome 1 through a translocation between chromosomes 1 and 11 (t[1; 11]) as well as additional chromosomal aberrations, including partial or complete monosomy of chromosomes 2, 6, 7, 11, 13, and 22. These molecular characteristics were already known to be associated with an aggressive course of the disease, and the patient was, therefore, included in a strict follow-up regime. From 2003 to 2019, the patient suffered multiple relapses and consecutive tumor resections.

METHODS

Tumor specimen from 2017 was examined using a genome-wide methylation analysis as well as a whole-genome sequencing.

RESULTS

These analyses confirmed the findings of 2002 and proved genetic alteration in the meningioma to be very stable over the time. Yet SMO and AKT1 mutations, which have been described to be paradigmatic in frontobasal meningioma, could not be found.

CONCLUSIONS

Genetic characteristics seem to be very stable during progression of the disease. The loss of 1p represents to be a potential marker for the poor clinical course of our child meningioma. In 2019, our patient passed away due to the progress of her meningioma disease.

Long-Term Clinical Outcome of First Recurrence Skull Base Meningiomas

Skull base meningiomas (SBMs) are considered to be less aggressive and have a slower growth rate than non-SBMs. However, SBMs often develop local recurrences after surgical resection. Gross total removal is difficult because SBMs are deep-seated tumors and involve critical neurovascular structures. The treatment strategy for recurrent SBMs remains controversial. The present study aimed to evaluate the long-term clinical course and prognostic factors associated with shorter progression-free survival (PFS) of recurrent SBMs. This retrospective study included 85 recurrent SBMs from 65 patients who underwent surgery from January 2005 to September 2018. Overall survival (OS) and PFS were evaluated, and the associations among shorter PFS and age, sex, tumor size, lesions, World Health Organization (WHO) grading, removal rate, and time since prior surgery were analyzed. The median follow-up period for PFS was 68 months. The 2-, 5-, and 10-year PFS rates were 68.0%, 52.8%, and 22.7%, respectively. WHO grade II or III, multiple lesions, and tumor size were significantly associated with shorter PFS (p < 0.0001, p = 0.030, and p = 0.173, respectively). Although, radiotherapy did not improve PFS and OS for overall patients, PFS of the patients with subtotal and partial removal for WHO grade II SBMs was significantly improved by the radiotherapy. Multivariate analysis identified WHO grade II or III and multiple lesions as independent prognostic factors for shorter PFS (p < 0.0001 and p = 0.040, respectively). It is essential to estimate the risks associated with shorter PFS for patients with recurrent SBMs to aid in the development of appropriate postoperative strategies.

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.

Multivariate risk factor analysis and literature review of postoperative deterioration in Karnofsky Performance Scale score in elderly patients with skull base meningioma

OBJECTIVE Elderly patients are particularly at risk for severe morbidity following surgery. Among the various risk factors, age and skull base location of meningioma are known to be poor prognostic factors in meningioma surgery. The authors conducted this study to analyze significant preoperative risk factors in elderly patients with skull base meningioma. METHODS A total of 265 elderly patients (≥ 65 years old) with meningioma were surgically treated at the authors' institute and affiliated hospitals between 2000 and 2016, and these cases were reviewed. Among them, 57 patients with skull base meningioma were evaluated. Among the various risk factors, the authors analyzed age, sex, Karnofsky Performance Scale (KPS) score, American Society of Anesthesiologists score, and tumor size, location, and pathology. Body mass index (BMI) and serum albumin were investigated as the frailty factors. The authors also reviewed 11 surgical studies of elderly patients ≥ 60 years old with meningioma. RESULTS The mean age was 72.4 ± 5.7 years, and 42 patients were female (73.6%). The mean size of meningioma was 36.6 ± 14.8 mm at the maximum diameter, and the mean follow-up period was 31.1 ± 31.5 months. (The continuous variables are expressed as the mean ± SD.) Histopathological investigation revealed a higher incidence (71.9%) of WHO Grade I. The rates of deterioration after surgery, at 3 months, and at 1 year were 33.3%, 37.3%, and 39.1%, respectively. Univariate analysis revealed location, preoperative KPS score, BMI level 2, and serum albumin level (p = 0.010, 0.017, 0.0012, and 0.0019, respectively) to be poor prognostic factors. Multivariate analysis revealed that location (p = 0.038) and BMI (p = 0.035) were risk factors for KPS score deterioration immediately after surgery. According to the 11 papers reviewed, the median rate (25th-75th percentile) of skull base-related location was 43.5% (39.6-47.75); for asymptomatic status the mean was 24%; and for mortality at 3 months and 1 year the medians were 6.3% (0.7-7.1) and 8% (4.8-9.4), respectively. CONCLUSION Careful preoperative assessment based on the frailty concept was essential for better outcome in elderly patients with skull base meningioma. The BMI is appropriate as a quantitative factor for measure of frailty, particularly in elderly individuals with skull base meningioma. Further prospective randomized controlled trials are necessary to validate frailty as a preoperative risk factor. Not only patient selection but also surgical timing was an important factor.

Prediction of High-Grade Histology and Recurrence in Meningiomas Using Routine Preoperative Magnetic Resonance Imaging: A Systematic Review

OBJECTIVE

Estimating the risk of recurrence after surgery remains crucial during care of patients with meningioma. Numerous studies identified correlations of characteristics on routine preoperative magnetic resonance imaging (MRI) with postoperative recurrence or high-grade histology but showed partially inconclusive results.

METHODS

A systematic review of the literature was performed about findings on preoperative MRI and their correlation with high-grade histology and recurrence. Quality of the included studies was analyzed using standardized Quality Assessment of Diagnostic Accuracy Studies criteria.

RESULTS

Among the 35 studies included, quality of the series according to the Quality Assessment of Diagnostic Accuracy Studies criteria differed widely. Remarkably, MRI variables found to be associated with high-grade histology were commonly not consistently associated with prognosis and vice versa. Correlations of the tumor size, the peritumoral edema size, and contrast-enhancement of the tumor capsule with high-grade histology were controversial. In most studies, non-skull base tumor location, cyst formation, heterogenous contrast-enhancement, an irregular tumor shape, and disruption of the tumor/brain border but not intensity of the lesion on T2-weighted images, calcifications, or bone involvement were associated with grade II/III histology. Although tumor and edema size were usually found to correlate with recurrence, heterogenous contrast enhancement, cyst formation, intensity of the tumor on T2-weighted MRI, and enhancement of the tumor capsule were mostly not related with progression.

CONCLUSIONS

Several mostly consistent but partially inconsistent variables associated with high-grade histology or prognosis were identified. Although standardized studies are needed to provide further clarification, consideration of these findings can help to improve estimation of prognosis and can therefore improve postoperative care in patients with meningioma.

Risk group-adapted adjuvant radiotherapy for WHO grade I and II skull base meningioma

PURPOSE

Salvage treatment including surgery and radiotherapy (RT) for recurrent or progressive meningioma is not an easy task, especially for the skull base location. And yet, criteria for adjuvant radiotherapy after initial surgery are not clearly defined for WHO grade I/II meningioma. We determined prognostic factors for recurrence and evaluated the benefit of risk group-adapted adjuvant RT for WHO grade I/II meningioma in the skull base.

METHODS

We reviewed 272 patients who underwent surgery and were pathologically confirmed with WHO grade I or II skull base meningioma between January 2000 and July 2017. Subgroup analyses were performed for WHO grade I (259 patients) and WHO grade II (13 patients) meningiomas to evaluate the benefit of RT in each subgroup.

RESULTS

Patients with WHO grade II meningiomas tended to present more neurologic symptoms and to receive RT more frequently. In prognostic factor analysis, tumor size (p = 0.039), surgical extent (p < 0.001), and RT (p = 0.005) were associated with recurrence-free survival (RFS). In subgroup analysis of WHO grade I, RFS was significantly better in RT group after matching other variables. The risk stratification was performed using three risk factors (petroclival location, tumor size, Simpson grade) in WHO grade I patients, and significantly different RFS was observed according to the risk group in non-RT patients.

CONCLUSIONS

Tumor size, Simpson grade, and adjuvant RT were prognostic factors. The risk group-adapted approach can facilitate the selection of patients who may benefit from adjuvant RT for WHO grade I/II skull base meningiomas.

Prediction of brain invasion in patients with meningiomas using preoperative magnetic resonance imaging

Brain invasion (BI) in meningiomas impacts WHO grading and therefore adjuvant treatment. However, BI is rare and neurosurgical sampling and neuropathological analyses are not standardised. Moreover, associations with imaging findings are sparsely known. Associations between BI and findings on preoperative MRI were investigated in 617 meningioma patients. BI was strongly correlated with other high-grade criteria (p<.001). Presence of a contrast enhancing tumour capsule, disruption of the arachnoid layer, intratumoural calcifications and T2-intensity were not related to high-grade histology or BI (p>.05, each). High-grade histology (p=.033) but not BI (p=.354) was associated with tumour location. Irregular tumour shape (OR: 3.33, 95%CI 1.33-8.30; p=.007), heterogeneous contrast enhancement (OR: 2.82, 95%CI 1.19-6.70; p=.015) and peritumoural edema (OR: 1.005 per ccm, 95%CI 1.001-1.008); p=.011) were associated with BI. Multivariable analyses identified only increasing edema volume (OR: 1.005 per ccm, 95%CI 1.002-1.009; p=.010) as a predictor for BI, independent of other histopathological high-grade criteria. We finally provide a new model to estimate the risk of BI using routine preoperative MRI. Several imaging characteristics were identified as predictors for BI. Consideration in clinical routine can increase the accuracy of the detection in neuropathological analyses.

Progesterone Receptor Is Responsible for Benign Biology of Skull Base Meningioma

OBJECTIVE

Many studies have been performed to evaluate the roles of estrogen receptor and progesterone receptor (PGR) in meningiomas, but their influence on tumor behavior remains unclear.

METHODS

We retrospectively analyzed patients with meningioma who underwent surgical resection at our institute. Patients with data for immunohistochemical staining of estrogen receptor, PGR, and Ki-67 were included.

RESULTS

The study included 161 patients comprising 61 skull base and 100 non-skull base meningiomas. Histologically, the number of patients with World Health Organization (WHO) grade I, II, and III disease were 132 (82.0%), 22 (14.7%), and 7 (4.4%), respectively. Tumor recurrence was observed in 21 (13.0%). Negative PGR, high Ki-67 index, incomplete resection, and WHO grade II or III were significantly correlated with tumor recurrence and shorter recurrence-free survival. Skull base meningiomas were difficult to remove entirely; 31 patients (50.8%) with skull base and 77 patients (77.0%) with non-skull base meningiomas had overall complete removal (P = 0.0006). Ki-67 indices, proportion of WHO grade II or III, and recurrence rate or recurrence-free survival did not differ between the tumor locations. The only difference was the proportion of patients with positive PGR, which was significantly higher for skull base meningiomas (61.5 ± 33.4% vs. 42.2 ± 35.7%, P = 0.0009).

CONCLUSIONS

Although skull base meningiomas are often incompletely resected, there were no differences in recurrence-free survival or recurrence rate between skull base and non-skull base meningiomas. As the Ki-67 index and WHO grade were not different between these locations, the high rate of positive PGR may be responsible for the benign biology of skull base meningiomas.

Surgical outcome in elderly patients with intracranial meningioma

The aim of this study was to examine the utility of surgical management of intracranial meningioma in elderly patients. A total of 138 patients with intracranial meningiomas who underwent surgery from 2008 to 2017 were divided into elderly (≥75 years old, n = 34) and younger (<75 years old, n = 104) groups. Clinical and radiological data were retrospectively analyzed. Total tumor removal was achieved in 79% of elderly patients, which was similar to that in young patients (85%, p = .81). The average preoperative Karnofsky performance scale score in elderly patients was significantly lower than that in young patients (70.6 vs. 90.4, respectively; p < .0001). However, the average change in the Karnofsky performance scale score after surgery was similar between the two groups (0.3 vs. -0.4, respectively; p = .36). Histopathological grading revealed that the incidence of malignant meningioma (World Health Organization grades II and III) was significantly higher in elderly patients than that in young patients (44% vs. 14%, respectively; p = .004). Among meningiomas showing chronological progression, World Health Organization grade II and III meningiomas accounted for 67% of tumors in elderly patients, but only 23% in younger patients (p = .01). These data suggest that surgical removal of meningiomas may be a safe and useful treatment strategy in elderly patients.

Boron Neutron Capture Therapy for High-Grade Skull-Base Meningioma

Objectives  Boron neutron capture therapy (BNCT) is a nuclear reaction-based tumor cell-selective particle irradiation that occurs when nonradioactive Boron-10 is irradiated with low-energy neutrons to produce high-energy α particles (10B [ n , α] 7Li). Possible complications associated with extended surgical resection render high-grade meningioma (HGM) a challenging pathology and skull-base meningiomas (SBMs) even more challenging. Lately, we have been trying to control HGMs using BNCT. This study aims to elucidate whether the recurrence and outcome of HGMs and SBMs differ based on their location. Design  Retrospective review. Setting  Osaka Medical College Hospital and Kyoto University Research Reactor Institute. Participants  Between 2005 and 2014, 31 patients with recurrent HGM (7 SBMs) were treated with BNCT. Main Outcome Measures  Overall survival and the subgroup analysis by the anatomical tumor location. Results  Positron emission tomography revealed that HGMs exhibited 3.8 times higher boron accumulation than the normal brain. Although tumors displayed transient increases in size in several cases, all lesions were found to decrease during observation. Furthermore, the median survival time of patients with SBMs post-BNCT and after being diagnosed as high-grade were 24.6 and 67.5 months, respectively (vs non-SBMs: 40.4 and 47.5 months). Conclusions  BNCT could be a robust and beneficial therapeutic modality for patients with high-grade SBMs.

Brain invasion in meningiomas-clinical considerations and impact of neuropathological evaluation: a systematic review

With the release of the 2016 edition of the World Health Organization (WHO) Classification of Central Nervous System Tumors, brain invasion in meningiomas has been added as a stand-alone criterion for atypia and can therefore impact grading and indirectly adjuvant therapy. Regarding this rising clinical importance, we have reviewed the current knowledge about brain invasion with emphasis on its implications on current and future clinical practice. We found various definitions of brain invasion and approaches for evaluation in surgically obtained specimens described over the past decades. This heterogeneity is reflected by weak correlation with prognosis and remains controversial. Similarly, associated clinical factors are largely unknown. Preoperative, imaging-guided detection of brain invasion is unspecific, and intraoperative assessment using standard and new high-magnification microscopic techniques remains imprecise. Despite the increasing knowledge about molecular alterations of the tumor/ brain surface, pharmacotherapeutic options targeting brain invasive meningiomas are lacking. Finally, we summarize the impact of brain invasion on histopathological grading in the WHO classifications of brain tumors since 1979.In conclusion, standardized neurosurgical sampling and neuropathological analyses could improve diagnostic reliability and reproducibility of future studies. Further research is needed to improve pre- and intraoperative visualization of brain invasion and to develop adjuvant, targeted therapies.

Frequent AKT1E17K mutations in skull base meningiomas are associated with mTOR and ERK1/2 activation and reduced time to tumor recurrence

Background

Skull base meningiomas are considered to be difficult for surgical treatment. We wondered whether genetic alterations recently identified in benign non-NF2-mutated World Health Organization (WHO) grade I meningiomas are related to clinical features of skull base meningiomas and whether druggable signaling pathways are activated.

Methods

We analyzed 93 skull base meningiomas (82 WHO grade I, 11 WHO grade II) for mutations of hot spots or the most relevant exons of AKT1, KLF4/TRAF7, SMO, PI3K, and the TERT promoter.

Results

The AKT1E17K mutation was present in 31% of patients and was related to meningothelial histology. AKT1E17K had a negative effect on the time to tumor recurrence. Analyses of activated signaling proteins revealed among AKT1E17K tumors a significantly higher rate of phospho-mammalian target of rapamycin (mTOR) and phospho-p70S6K+ tumors. AKT1E17K tumors with immunoexpression of phospho-extracellular signal-regulated kinase 1 or 2 (ERK1/2) were characterized by significantly shorter time to tumor recurrence compared with AKT1wt tumors expressing phospho-ERK1/2 (P = .046). KLF4 mutations (K409Q) were present in 11.8% of cases, with significant association to the secretory/transitional subtype (P < .001). The presence of the KLF4 K409Q mutation was associated with favorable outcome. One phosphatidylinositol-3 kinase (PI3K) mutation but no SMO or TERT promoter mutation was found.

Conclusions

AKT1E17K mutation is frequent in skull base meningiomas, results in activation of the mTOR and ERK1/2 signaling pathways, and has negative impact on tumor recurrence. Patients with skull base meningiomas with AKT1E17K mutation might benefit from additional treatment targeting the mTOR pathway. Generally, the PI3K-Akt-mTOR axis might be a potential target for kinase inhibitors in these tumors.