Clinical and radiological features related to the growth potential of meningioma

Calcified Meningiomas Demonstrate Equivocal Grade, Proliferation, and Immediate Surgical Outcomes

BACKGROUND/OBJECTIVE

Meningioma calcification is thought to predict reduced growth potential and aggression. However, historical studies have primarily focused on correlating calcification in small meningiomas (diameter less than 2.5 cm) rather than analyzing characteristics of calcified meningiomas across all sizes. In this study, we investigate the pathologic and clinical implications of meningioma calcification.

METHODS

We utilized a historical database of 342 consecutive newly diagnosed intracranial meningiomas with preoperative computed tomography and magnetic resonance imaging scans treated at a single institution from 2005 to 2019. We correlated the presence of calcification with patient demographics, grade, Mindbomb Homolog-1 index, location, volume, Simpson grade, and recurrence using both univariate and multivariate generalized linear models.

RESULTS

On univariate analysis, no single variable correlated with tumor calcification. Notably, neither tumor 2021 World Health Organization grade (P = 0.91) nor Mindbomb Homolog-1 index (P = 0.62) predicted calcification. After accounting for demographic characteristics and tumor volume and location, there was no significant association between 2021 World Health Organization grade (P = 0.52) and Mindbomb Homolog-1 index (P = 0.54) and calcification. Calcification had no influence on resection grade (P = 0.59) or recurrence (P = 0.80).

CONCLUSIONS

In this series, calcified meningiomas exhibited similar 2021 World Health Organization tumor grading distribution, proliferation indexes, and immediate surgical outcomes compared to their noncalcified counterparts. These findings question the historical role of using meningioma calcification as an independent guide to their management.

Meningioma grading via diagnostic imaging: A systematic review and meta-analysis

PURPOSE

Meningioma is the most common intracranial tumor, graded on pathology using WHO criteria to predict tumor course and treatment. However, pathological grading via biopsy may not be possible in cases with poor surgical access due to tumor location. Therefore, our systematic review aims to evaluate whether diagnostic imaging features can differentiate high grade (HG) from low grade (LG) meningiomas as an alternative to pathological grading.

METHODS

Three databases were searched for primary studies that either use routine magnetic resonance imaging (MRI) or computed tomography (CT) to assess pathologically WHO-graded meningiomas. Two investigators independently screened and extracted data from included studies.

RESULTS

24 studies met our inclusion criteria with 12 significant (p < 0.05) CT and MRI features identified for differentiating HG from LG meningiomas. Cystic changes in the tumor had the highest specificity (93.4%) and irregular tumor-brain interface had the highest positive predictive value (65.0%). Mass effect had the highest sensitivity (81.0%) and negative predictive value (90.7%) of all imaging features. Imaging feature with the highest accuracy for identifying HG disease was irregular tumor-brain interface (79.7%). Irregular tumor-brain interface and heterogenous tumor enhancement had the highest AUC values of 0.788 and 0.703, respectively.

CONCLUSION

Our systematic review highlight imaging features that can help differentiate HG from LG meningiomas.

Challenging Resection of Bilateral Parasagittal and Falcine Meningioma Involving Both Anterior Third and Middle Third of the Superior Sagittal Sinus: A Case Report and Literature Review

Meningiomas typically manifest as benign, slow-growing, and well-defined tumors on a macroscopic level and are usually asymptomatic. However, the mass effect caused by large meningiomas may lead to various neurological symptoms, commonly headaches and visual problems. Radiological imaging can establish the diagnosis, and a biopsy can provide a definitive diagnosis. Our case report describes the surgical intervention for bilateral parasagittal-falcine meningioma in a 57-year-old male who presented to the emergency department with a tonic-clonic seizure. On examination, he had a bifrontal longitudinal mass. Magnetic resonance imaging (MRI) revealed a large anterior superior falcine extra-axial mass, measuring about 5.7 x 5.3 x 3.1 cm, with surrounding vasogenic edema and superior sagittal sinus invasion. He underwent surgery for tumor resection involving the anterior third and middle third of the superior sagittal sinus without radiotherapy. He did not develop any intraoperative complications, and during the post-operative evaluation, he was symptom-free. A follow-up MRI with contrast performed three months later showed no neurological complications or recurrent tumor. To achieve better outcomes, surgical intervention for parasagittal and falcine meningiomas involving the superior sagittal sinus should aim to eliminate clinical signs, control tumor growth, and prevent neurological deterioration post-operatively.

Incidental Meningiomas: Potential Predictors of Growth and Current State of Management

The rise in availability of neuroimaging has led to an increase in incidentally discovered meningiomas. These tumors are typically asymptomatic and tend to display slow growth. Treatment options include observation with serial monitoring, radiation, and surgery. Although optimal management is unclear, clinicians recommend a conservative approach, which preserves quality of life and limits unnecessary intervention. Several risk factors have been investigated for their potential utility in the development of prognostic models for risk assessment. Herein, the authors review the current literature on incidental meningiomas, focusing their discussion on potential predictive factors for tumor growth and appropriate management practices.

Impact of Shape Irregularity in Medial Sphenoid Wing Meningiomas on Postoperative Cranial Nerve Functioning, Proliferation, and Progression-Free Survival

Medial sphenoid wing meningiomas (MSWM) are surgically challenging skull base tumors. Irregular tumor shapes are thought to be linked to histopathology. The present study aims to investigate the impact of tumor shape on postoperative functioning, progression-free survival, and neuropathology. This monocentric study included 74 patients who underwent surgery for primary sporadic MSWM (WHO grades 1 and 2) between 2010 and 2021. Furthermore, a systematic review of the literature regarding meningioma shape and the MIB-1 index was performed. Irregular MSWM shapes were identified in 31 patients (41.9%). Multivariable analysis revealed that irregular shape was associated with postoperative cranial nerve deficits (OR: 5.75, 95% CI: 1.15-28.63, p = 0.033). In multivariable Cox regression analysis, irregular MSWM shape was independently associated with tumor progression (HR:8.0, 95% CI: 1.04-62.10, p = 0.046). Multivariable regression analysis showed that irregular shape is independently associated with an increased MIB-1 index (OR: 7.59, 95% CI: 2.04-28.25, p = 0.003). A systematic review of the literature and pooled data analysis, including the present study, showed that irregularly shaped meningiomas had an increase of 1.98 (95% CI: 1.38-2.59, p < 0.001) in the MIB-1 index. Irregular MSWM shape is independently associated with an increased risk of postoperative cranial nerve deficits and a shortened time to tumor progression. Irregular MSWM shapes might be caused by highly proliferative tumors.

Factors associated with radiation toxicity and long-term tumor control more than 10 years after Gamma Knife surgery for non-skull base, nonperioptic benign supratentorial meningiomas

OBJECTIVE

Gamma Knife surgery (GKS) is a well-established treatment for benign intracranial meningiomas; however, the dosimetric factors associated with long-term GKS efficacy and safety remain to be elucidated. Using data obtained with at least 10 years of follow-up, the authors aimed 1) to analyze GKS efficacy and safety for the treatment of benign meningiomas confined to non-skull base, nonperioptic supratentorial locations and 2) to determine the radiation dose window that allows for long-term efficacy and safety, namely the minimum dose to achieve long-term local control (LC) and the maximum safe dose to avoid adverse radiation effects (AREs).

METHODS

A retrospective analysis was performed on patients who underwent GKS for benign meningiomas in the abovementioned location at the authors' institution between 1998 and 2010 and who received follow-up for more than 10 years. The authors meticulously extracted the values of various dosimetric factors by using a dose-volume histogram. Cox proportional hazard regression analyses were performed to investigate the dosimetric factors associated with LC and ARE.

RESULTS

Fifty-five patients (male/female ratio 1:4.2) with 68 tumors were enrolled. The median (range) gross target volume and marginal dose were 4.2 (0.2-31.7) cm3 and 14.3 (9-20) Gy, respectively. In total, 23.5% of tumors progressed at an average of 72 months, with 10- and 15-year progression-free survival rates of 80.9% and 73.5%, respectively. In univariate analysis, higher marginal dose, coverage (%), Dmin, D98%, Dmean, D2%, Dmax, and Paddick conformity index were significantly associated with LC. In multivariate analysis, D98% was the significant factor, with a cutoff value of 11 Gy (HR 0.754, p < 0.001). Symptomatic AREs occurred in 7 patients at an average of 7 months after GKS. AREs were significantly associated with the volume of normal tissue irradiated with more than 14 Gy (nV14Gy), with a cutoff value of 0.66 cm3 (HR 2.459, p = 0.002).

CONCLUSIONS

D98% was a barometer of the minimum required dose associated with long-term LC, and nV14Gy was related to symptomatic AREs. The authors recommend a marginal dose ranging from 11 to 14 Gy to achieve long-term efficacy and safety in patients with non-skull base, nonperioptic benign supratentorial meningiomas, with the assumption of thorough tumor coverage.

Imaging score for differentiation of meningioma grade

PURPOSE

We sought to establish a comprehensive imaging score indicating the likelihood of higher WHO grade meningiomas pre-operatively.

METHODS

All surgical intracranial meningioma patients at our institution between 2014 and 2018 underwent retrospective chart review. Preoperative MRI sequences were reviewed, and imaging features were included in the score based on statistical and clinical significance. Point values for each significant feature were assigned based on the beta coefficients obtained from multivariate analysis. The imaging score was calculated by adding up the points, for a total score of 0 to 5. The predictive ability of the score to identify higher-grade meningiomas was evaluated.

RESULTS

Ninety patients, 50% of whom had a postoperative diagnosis of WHO grade II meningioma, were included. The mean age for the population was 59.9 years and 70% were female. Tumor volume ≥ 36.0 cc was assigned 2 points, presence of irregular tumor borders was assigned 2 points, and presence of peritumoral edema was assigned 1 point. The probability of having a WHO grade II meningioma was 0% with a score of 0, 25.0% with a score of 1, 38.5% with a score of 2, 65.4% with a score of 3, and 83.3% with a score of 4 or greater. A threshold of ≥ 3 points achieved a recall of 0.80, precision of 0.73, F1-score of 0.77, accuracy of 0.76, and AUC of 0.82.

CONCLUSION

The proposed imaging scoring system had good predictive capability for WHO grade II meningiomas with good discrimination and calibration. External validation is needed.

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.

Surgical complications and recurrence factors for asymptomatic meningiomas: a single-center retrospective study

PURPOSE

Observation is the first management option in asymptomatic meningiomas, but when an enlargement or mass effect is observed, surgery is indicated. This study is aimed at exploring risk factors for complications and recurrence after surgery for asymptomatic meningioma. We also examined the impact of preoperative tumor embolization, which is considered controversial.

METHODS

We retrospectively reviewed 109 patients with primary asymptomatic meningiomas surgically treated at our institute between April 2007 and March 2021. Patients who only had headaches as a nonspecific complaint were included in the asymptomatic group. Complications, time to recurrence, and Glasgow Outcome Scale (GOS) score were the endpoints of the study. Risk factors for complications and recurrence were explored. Moreover, the effect of the resection on nonspecific headaches was also explored.

RESULTS

The permanent postoperative complication rate related to the surgical procedure was 1.8%. Of the total, 107 patients (98.2%) with asymptomatic meningiomas who were surgically treated achieved a GOS score of 5 1 year after the operation. Preoperative headache was present in 31 patients and improved postoperatively in 21 patients. Multivariate analysis using the Cox proportional hazard model showed that preoperative tumor embolization with > 80% resolution of tumor staining (p < 0.001) was negatively related to recurrence, whereas age (p = 0.046) and Simpson grade IV resection (p = 0.041) were positively related to recurrence.

CONCLUSION

Although surgery for asymptomatic meningiomas can, in many cases, be safe, it is not free of complications Thus, surgical intervention for asymptomatic meningiomas should be considered cautiously. However, more than half the patients with headaches showed improvement. Simpson grade IV resection cases should be assessed for recurrence, and preoperative tumor embolization might be effective in controlling recurrence.

Clinical features, radiological findings, and prognostic factors for primary intracranial chordoid meningioma

OBJECTIVES

Chordoid meningioma (CM) is an infrequent histologic subtype of meningiomas. Owing to its low occurrence, this subtype has been rarely described. Our subject was to explore the clinical features, radiological characteristics, and prognostic factors of primary intracranial chordoid meningioma.

METHODS

We reviewed the medical records and collected follow-up information of 34 cases who had been surgically treated and histologically diagnosed with CM at the Department of Neurosurgery, West-China Hospital of Sichuan University, from January 2009 to December 2021.

RESULTS

Among all 7,950 meningioma cases, the proportion of primary intracranial CM was 0.43% (34/7,950). The median diagnosis age was 47 (ranging from 12 to 74) and the gender ratio (male to female) was 2.1:1. For radiological features, heterogeneous enhancement, skull base, and ventricular localization, cystic degeneration and dural tail sign were common in CM cases. In treatment, gross total resection (GTR) was achieved in 22/34 cases (64.7%) and subtotal resection (STR) was achieved in 12/34 cases (35.3%). Further, 11/34 patients (32.4%) had received postoperative adjuvant radiotherapy (RT). The follow-up duration ranged from 4 to 157 months after operation. The progression rate was 20.7% (6/29) and the median of PFS was 38 months. By survival analysis, accepting adjuvant radiotherapy and achieving GTR were correlated with longer progression-free survival for prognosis.

CONCLUSION

CM is a rare subtype of meningiomas. In our series, it mainly involved adults and did not show a predilection for women compared with meningiomas in general. For a better prognosis, gross total resection and postoperative adjuvant radiotherapy are recommended. Nevertheless, due to the restriction of the series sample, patients lost for follow-up and inherent biases of a retrospective study, more cases and a shorter follow-up duration are needed for better management of chordoid meningioma.

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.

A radiomics nomogram for predicting the meningioma grade based on enhanced T1WI images

OBJECTIVES

The objective of this study was to develop a radiomics nomogram for predicting the meningioma grade based on enhanced T1 weighted imaging (T1WI) images.

METHODS

188 patients with meningioma were analyzed retrospectively. There were 94 high-grade meningioma to form high-grade group and 94 low-grade meningioma were selected randomly to form low-grade group. Clinical data and MRI features were analyzed and compared. The clinical model was built by using the significant variables. The least absolute shrinkage and selection operator regression was used to select the most valuable radiomics feature. The radiomics signature was built and the Rad-score was calculated. The radiomics nomogram was developed by the significant variables of the clinical factors and Rad-score. The calibration curve and the Hosmer-Lemeshow test were used to evaluate the radiomics nomogram. Different models were compared by Delong test and decision curve analysis curve.

RESULTS

The sex, size and surrounding invasion were used to build clinical model. The area under the receiver operator characteristic curve (AUC) of clinical model was 0.870 (95% CI: 0.782-0.959). Nine features were used to construct the radiomics signature. The AUC of the radiomics signature was 0.885 (95% CI: 0.802-0.968). The AUC of radiomics nomogram was 0.952 (95% CI: 0.904-1). The AUC of radiomics nomogram was higher than that of clinical model and radiomics signature with a significant difference (p＜0.05). The decision curve analysis curve showed that the radiomics nomogram had a larger net benefit than the clinical model and radiomics signature.

CONCLUSION

The radiomics nomogram based on enhanced T1 weighted imaging images for predicting the meningioma grade showed high predictive value and might contribute to the diagnosis and treatment of meningioma.

ADVANCES IN KNOWLEDGE

1. We first constructed a radiomic nomogram to predict the meningioma grade.2. We compared the results of the clinical model, radiomics signature and radiomics nomogram.

Low-Dose Acetylsalicylic Acid Treatment in Non-Skull-Base Meningiomas: Impact on Tumor Proliferation and Seizure Burden

MIB-1 index is an important predictor of meningioma progression and was found to be correlated with COX-2 expression. However, the impact of low-dose acetylsalicylic acid (ASA) on MIB-1 index and clinical symptoms is unclear. Between 2009 and 2022, 710 patients with clinical data, tumor-imaging data, inflammatory laboratory (plasma fibrinogen, serum C-reactive protein) data, and neuropathological reports underwent surgery for primary cranial WHO grade 1 and 2 meningioma. ASA intake was found to be significantly associated with a low MIB-1 labeling index in female patients ≥ 60 years. Multivariable analysis demonstrated that female patients ≥ 60 years with a non-skull-base meningioma taking ASA had a significantly lower MIB-1 index (OR: 2.6, 95%: 1.0–6.6, p = 0.04). Furthermore, the intake of ASA was independently associated with a reduced burden of symptomatic epilepsy at presentation in non-skull-base meningiomas in both genders (OR: 3.8, 95%CI: 1.3–10.6, p = 0.03). ASA intake might have an anti-proliferative effect in the subgroup of elderly female patients with non-skull-base meningiomas. Furthermore, anti-inflammatory therapy seems to reduce the burden of symptomatic epilepsy in non-skull-base meningiomas. Further research is needed to investigate the role of anti-inflammatory therapy in non-skull-base meningiomas.

MAC-spinal meningioma score: A proposal for a quick-to-use scoring sheet of the MIB-1 index in sporadic spinal meningiomas

Objective

MIB-1 index is an important predictor of meningioma progression. However, MIB-1 index is not available in the preoperative tailored medical decision-making process. A preoperative scoring sheet independently estimating MIB-1 indices in spinal meningioma (SM) patients has not been investigated so far.

Methods

Between 2000 and 2020, 128 patients with clinical data, tumor imaging data, inflammatory laboratory (plasma fibrinogen, serum C-reactive protein) data, and neuropathological reports (MIB-1, mitotic count, CD68 staining) underwent surgery for spinal WHO grade 1 and 2 meningioma.

Results

An optimal MIB-1 index cut-off value (≥5/<5) predicting recurrence was calculated by ROC curve analysis (AUC: 0.83; 95%CI: 0.71-0.96). An increased MIB-1 index (≥5%) was observed in 55 patients (43.0%) and multivariable analysis revealed significant associations with baseline Modified McCormick Scale ≥2, age ≥65, and absence of calcification. A four-point scoring sheet (MAC-Spinal Meningioma) based on Modified McCormick, Age, and Calcification facilitates prediction of the MIB-1 index (sensitivity 71.1%, specificity 60.0%). Among those patients with a preoperative MAC-Meningioma Score ≥3, the probability of a MIB-1 index ≥5% was 81.3%.

Conclusion

This novel score (MAC-Spinal Meningioma) supports the preoperative estimation of an increased MIB-1 index, which might support preoperative patient-surgeon consultation, surgical decision making and enable a tailored follow-up schedule or an individual watch-and-wait strategy.

Natural history and volumetric analysis of meningiomas in neurofibromatosis type 2

OBJECTIVE

The objective of this paper was to describe the volumetric natural history of meningiomas in patients with neurofibromatosis type 2 (NF2).

METHODS

The authors performed a retrospective descriptive study by reviewing NF2 patients with meningiomas at their institution between 2000 and 2019. Demographic data were collected from the electronic medical records. Tumor volume was collected using volumetric segmentation software. Imaging characteristics including peritumoral brain edema (PTBE) and tumor calcification were collected for each patient from their first to most recent MRI at the authors’ institution. An increase of 15% or more per year from original tumor size was used as the cutoff to define growth.

RESULTS

A total of 137 meningiomas from 48 patients were included in the analysis. The average number of tumors per person was 2.9. Ninety-nine (72.3%) tumors were in female patients. The median length of follow-up from first imaging to last imaging was 32 months (IQR 10.9, 68.3 months). Most tumors were located in the cerebral convexity (24.8%), followed by the falcine region (18.2%) and spine (10.2%). The median tumor growth was 0.12 cm3/yr (IQR 0.03, 0.52 cm3/yr). At the time of first imaging, 21.9% of tumors had calcifications, while 13.9% of meningiomas had PTBE. Of 137 tumors, 52 showed growth. Characteristics associated with tumor growth included PTBE (OR 9.12, 95% CI 1.48–56.4), tumor volume (per cm3) at first imaging (OR 0.91, 95% CI 0.83–0.99), and 10-year increased age at first imaging (OR 0.57, 95% CI 0.43–0.74). PTBE had the shortest median time to growth at 9.2 months.

CONCLUSIONS

Although the majority of NF2-associated meningiomas do not grow in the short term, a wide range of growth patterns can be seen. Younger age at first imaging and presence of PTBE are associated with growth. Patients with these characteristics likely benefit from closer follow-up.

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.

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.

Lateral Ventricular Meningiomas: Clinical Features, Radiological Findings and Long-Term Outcomes

Purpose

Lateral ventricle meningioma (LVM) is a rare type of intracranial meningioma, which has been rarely studied. It has different clinical features, imaging features, and long-term results from other locations. This study investigated the epidemiology, clinical characteristics and prognosis of LVM and comprehensively describes its characteristics.

Methods

This article analyzes the LVMs that were diagnosed pathologically in West China hospital between January 1, 2009 and July 1 2020. Demographic information, imaging characteristics and prognostic factors are discussed. Data analysis was performed using SPSS 23.0 and R version 3.5.3.

Results

We collected 7202 meningiomas and 195 LVMs (136 females; median age, 46 years; range, 5–81 years) were included in this study. Gross total resection was completed in 189 patients. The OS rate was 93.8%, and the recurrence rate was 5.2%. Multivariate regression analysis showed that sex (P = 0.01) and tumor size (P = 0.018) were related to WHO grade. Postoperative KPS (P = 0.003) was associated with OS. WHO grade (P = 0.025), extent of tumor resection (P < 0.001), and hospital day (P=0.028) were associated with recurrence.

Conclusion

LVMs require long-term follow-up, individualized treatment, and follow-up strategies to be formulated according to the relevant risk factors.

FORGE: A Novel Scoring System to Predict the MIB-1 Labeling Index in Intracranial Meningiomas

Simple Summary

Meningiomas are predominantly benign intracranial tumors, and surgical therapy represents the treatment of choice. However, the risk of recurrence and scheduling of follow-up intervals are significantly influenced by immunohistochemical items such as the MIB-1 labeling index. To date, it is not possible to integrate this essential information into the pre- or intraoperative surgical decision making. In the present study, we therefore analyzed baseline variables associated with the MIB-1 labeling index. We found four easily identifiable and routinely recorded risk factors for an increased MIB-1 index and developed a simple and quick-to-use score that allows us to estimate the risk of an elevated MIB-1 index prior to the surgical resection. Furthermore, this score seems to predict the progression-free survival in intracranial meningiomas. We believe that this score might us to more reliably guide patients in preoperative surgical strategy planning and postoperative follow-up scheduling.

Abstract

The MIB-1 index is an essential predictor of progression-free-survival (PFS) in meningioma. To date, the MIB-1 index is not available in preoperative treatment planning. A preoperative score estimating the MIB-1 index in patients with intracranial meningiomas has not been investigated so far. Between 2013 and 2019, 208 patients with tumor morphology data, MIB-1 index data, and plasma fibrinogen and serum C-reactive protein (CRP) data underwent surgery for intracranial WHO grade I and II meningioma. An optimal MIB-1 index cut-off value (≥6/<6) in the prediction of recurrence was determined by ROC curve analysis (AUC: 0.71; 95% CI: 0.55–0.87). A high MIB-1 index (≥6%) was present in 50 cases (24.0%) and was significantly associated with male sex, peritumoral edema, low baseline CRP, and low fibrinogen level in the multivariate analysis. A scoring system (“FORGE”) based on sex, peritumoral edema, preoperative CRP value, and plasma fibrinogen level supports prediction of the MIB-1 index (sensitivity 62%, specificity 79%). The MIB-1 labeling index and the FORGE score are significantly associated with an increased risk of poor PFS time. We suggest a novel score (“FORGE”) to preoperatively estimate the risk of an increased MIB-1 index (≥6%), which might help in surgical decision making and follow-up interval determination and inform future trials investigating inflammatory burden and proliferative activity.

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.

Outcomes from treatment of asymptomatic skull base meningioma with stereotactic radiosurgery

BACKGROUND

Optimal management of asymptomatic skull base meningiomas is controversial. We evaluated the safety and efficiency of Gamma Knife radiosurgery (GKRS) for the management of asymptomatic skull base meningiomas.

METHODS

This retrospective study involved patients managed with GKRS for asymptomatic, skull base meningiomas from 1997 to 2019. Patient clinico-radiologic data, tumor characteristics, and procedural details were analyzed. Favorable outcome was defined as lack of procedure-related mortality or permanent neurologic morbidity and radiologic evidence of tumor control. Tumor progression and regression were defined as an increase or decrease of > 20% in volume from baseline to the last neuroimaging study respectively. Tumor volumes within ± 20% of baseline volume were considered stable.

RESULTS

Thirty-seven patients (30 women), median age 68 years old (range 42-83 months) were managed with a single-session GKRS for 40 asymptomatic, skull base meningiomas. At a median clinical follow-up of 58.5 months (range 14-150 months), no mortality associated with the procedure or the treated tumor was noted. Permanent neurologic morbidity was 2.75%. There was a statistically significant decrease in mean tumor volume (p < 0.001) from 4.04 cc (SD 3.09 cc) prior to radiosurgery to 2.73 cc (SD 2.24 cc) at last follow-up. Higher margin dose was associated with tumor regression at last follow-up (HR = 1.351; 95%CI [1.094-1.669]; p = 0.05).

CONCLUSION

As compared to natural history studies, GKRS affords long-standing tumor control and neurologic preservation in the vast majority of patients treated for asymptomatic, skull base meningiomas. Further study is necessary to identify the optimal management of asymptomatic skull base meningiomas.

MRI predictors for brain invasion in meningiomas

BACKGROUND AND PURPOSE

In the 2016 revision of the World Health Organization classification of central nervous system tumours, brain invasion was added as an independent histological criterion for the diagnosis of a World Health Organization grade II atypical meningioma. The aim of this study was to assess whether magnetic resonance imaging characteristics can predict brain invasion for meningiomas.

MATERIALS AND METHODS

We conducted a retrospective review of all meningiomas resected at our institution between 2005 and 2016 which had preoperative magnetic resonance imaging and included brain tissue within the pathology specimen. One hundred meningiomas were included in the study, 60 of which had histopathological brain invasion, 40 of which did not. Magnetic resonance imaging characteristics of tumours were evaluated for potential predictors of brain invasion. Tumour location, size, perilesional oedema, contour, cerebrospinal fluid cleft, peritumoral cyst, dural venous sinus invasion, bone invasion, hyperostosis and the presence of enlarged pial arteries and veins were evaluated. Data were analysed using conventional chi-square, Fisher's exact test and logistic regression.

RESULTS

The volume of peritumoral oedema was significantly higher in the brain-invasive meningioma group compared to the non-brain-invasive group. The presence of a complete cleft was a rare finding that was only found in non-brain-invasive meningiomas. The presence of enlarged pial feeding arteries was a rare finding that was only found in brain-invasive meningiomas.

CONCLUSIONS

An increased volume of perilesional oedema is associated with the likelihood of brain invasion for meningiomas.

A Novel Scoring System Based on Preoperative Routine Blood Test in Predicting Prognosis of Atypical Meningioma

Purpose

The aim of this study was to explore the correlation and clinical significance of preoperative fibrinogen and neutrophil-lymphocyte ratio (F-NLR) scoring system with 3-year progression-free survival (PFS) of patients with atypical meningioma.

Materials and Methods

Clinical, pathological, radiological, and laboratory variables were collected to analyze their correlation with 3-year PFS in the training set with 163 patients. Patients were classified by different F-NLR scores (0, 1, or 2). External validation for the predictive value of F-NLR scoring system was performed in the validation set with 105 patients.

Results

Overall, 37.3% (100 of 268) of the enrolled patients were male. The scoring system showed good performance in predicting 3-year PFS (AUC = 0.872, 95%CI = 0.811–0.919, sensitivity = 66.1%, specificity = 93.3%, and Youden index = 0.594). DeLong’s test indicated that the AUC of F-NLR scoring system was significantly greater than that of fibrinogen level and NLR (Z = 2.929, P = 0.003; Z = 3.376, P < 0.001). Multivariate Cox analysis revealed that tumor size (HR = 1.39, 95%CI = 1.10–1.76, P = 0.007), tumor location (HR = 3.11, 95%CI = 1.60–6.95, P = 0.001), and F-NLR score (score of 1: HR = 12.78, 95%CI = 3.78–43.08, P < 0.001; score of 2: HR = 44.58, 95%CI = 13.02–152.65, P < 0.001) remained significantly associated with 3-year PFS. The good predictive performance of F-NLR scoring system was also demonstrated in the validation set (AUC = 0.824, 95%CI = 0.738–0.891, sensitivity = 62.5%, specificity = 87.9%, and Youden index = 0.504).

Conclusion

Our study confirmed the correlation and clinical significance of preoperative F-NLR scoring system with 3-year PFS of patients with atypical meningioma. A prospective and large-scale study is required to validate our findings.

Imaging and diagnostic advances for intracranial meningiomas

The archetypal imaging characteristics of meningiomas are among the most stereotypic of all central nervous system (CNS) tumors. In the era of plain film and ventriculography, imaging was only performed if a mass was suspected, and their results were more suggestive than definitive. Following more than a century of technological development, we can now rely on imaging to non-invasively diagnose meningioma with great confidence and precisely delineate the locations of these tumors relative to their surrounding structures to inform treatment planning. Asymptomatic meningiomas may be identified and their growth monitored over time; moreover, imaging routinely serves as an essential tool to survey tumor burden at various stages during the course of treatment, thereby providing guidance on their effectiveness or the need for further intervention. Modern radiological techniques are expanding the power of imaging from tumor detection and monitoring to include extraction of biologic information from advanced analysis of radiological parameters. These contemporary approaches have led to promising attempts to predict tumor grade and, in turn, contribute prognostic data. In this supplement article, we review important current and future aspects of imaging in the diagnosis and management of meningioma, including conventional and advanced imaging techniques using CT, MRI, and nuclear medicine.

Predicting the risk of postoperative recurrence and high-grade histology in patients with intracranial meningiomas using routine preoperative MRI

Risk factors for prediction of prognosis in meningiomas derivable from routine preoperative magnetic resonance imaging (pMRI) remain elusive. Correlations of tumor and edema volume, disruption of the arachnoid layer, heterogeneity of contrast enhancement, enhancement of the capsule, T2-intensity, tumor shape, and calcifications on pMRI with tumor recurrence and high-grade (WHO grade II/III) histology were analyzed in 565 patients who underwent surgery for WHO grade I (N = 516, 91%) or II/III (high-grade histology, N = 49, 9%) meningioma between 1991 and 2018. Edema volume (OR, 1.00; p = 0.003), heterogeneous contrast enhancement (OR, 3.10; p < 0.001), and an irregular shape (OR, 2.16; p = 0.015) were associated with high-grade histology. Multivariate analyses confirmed edema volume (OR, 1.00; p = 0.037) and heterogeneous contrast enhancement (OR, 2.51; p = 0.014) as risk factors for high-grade histology. Tumor volume (HR, 1.01; p = 0.045), disruption of the arachnoid layer (HR, 2.50; p = 0.003), heterogeneous contrast enhancement (HR, 2.05; p = 0.007), and an irregular tumor shape (HR, 2.57; p = 0.001) were correlated with recurrence. Multivariate analyses confirmed tumor volume (HR, 1.01; p = 0.032) and disruption of the arachnoid layer (HR, 2.44; p = 0.013) as risk factors for recurrence, independent of histology. Subgroup analyses revealed disruption of the arachnoid layer (HR, 9.41; p < 0.001) as a stronger risk factor for recurrence than high-grade histology (HR, 5.15; p = 0.001). Routine pMRI contains relevant information about the risk of recurrence or high-grade histology of meningioma patients. Loss of integrity of the arachnoid layer on MRI had a higher prognostic value than the WHO grading, and underlying histological or molecular alterations remain to be determined.

A practical predictor of the growth potential of benign meningiomas: Hypointensity of surface layer in T2-weighted magnetic resonance imaging

BACKGROUND

Accurate evaluation of proliferative potential is particularly important in the clinical management of individual patients with meningiomas. We introduce a new feature in the parenchyma of meningioma, namely, hypointensity of the surface layer (HSL), on T2-weighted MR images and compare it with a cellular proliferation index and growth speed.

MATERIALS AND METHODS

We retrospectively analyzed the records of consecutive patients with WHO grade I meningiomas in two institutes: an operated group with 124 meningiomas resected in one institute, and an observed group with 89 meningiomas monitored without surgery in the other. Proliferative potential was evaluated using the MIB-1 labeling index (MIB-1 LI) for the operated group and using the relative growth rate on serial MR images for the observed group.

RESULTS

In the operated group, 60 (48.4%) meningiomas exhibited HSL. HSL-positive meningiomas were significantly smaller in size and more often calcified than HSL-negative ones. Univariate analysis showed that HSL negativity, large size, no calcification, and surrounding brain edema were significantly associated with high MIB-1 LI (p < 0.05). Multivariate analysis demonstrated that only HSL was significantly related to MIB-1 LI (p = 0.001). HSL did not correlate with tumor recurrence after resection. In the observed group, 43 (48.3%) meningiomas exhibited HSL and they presented a significantly slow relative growth rate.

CONCLUSIONS

HSL is a simple and new radiological feature indicative of low proliferative potential and a low risk of enlargement of meningiomas. The presence or absence of HSL may serve as a key parameter for the selection of aggressive treatment or active observation.

Natural history of intracranial meningiomas

We know that the extent of resection is the greatest predictor of long-term survival. However, the potential tradeoff for gross total resection in difficult locations is diminished quality of life. Benign subtotally resected or small incidentally discovered meningiomas may be followed clinically especially in the elderly. In addition, radiosurgery plays a role in the treatment of meningiomas as a primary treatment modality, or as a salvage therapy. Decisions regarding management should be made with an understanding of the natural history and rate of growth. In this chapter we review the known meningioma epidemiology as well as the growth patterns of meningiomas based upon location.

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.

Metastatic meningioma: Case report of a WHO grade I meningioma with liver metastases and review of the literature

Meningioma represents the most frequently diagnosed primary brain tumor, accounting for over one-third of central nervous system neoplasms. The majority of tumors are categorized as benign. However, albeit rarely, meningiomas may metastasize to distant sites. We describe a 78-year-old man with a history of recurrent World Health Organization grade I meningioma managed who presented for evaluation of weakness and urinary retention. A computed tomography scan obtained in the emergency department revealed multiple scattered low-density liver lesions. Subsequent magnetic resonance imaging showed a 5.5-centimeter heterogeneous enhancing mass with 2 smaller enhancing lesions suspicious for a primary or secondary malignant neoplasm. Microscopic examination of a tissue sample obtained via liver biopsy demonstrated a metastatic spindle cell neoplasm with histologic features compatible with a diagnosis of World Health Organization grade I transitional meningioma. The patient was referred to hematology/oncology for systemic therapy.

Growth prediction in asymptomatic meningiomas: the utility of the AIMSS score

BACKGROUND

Management of asymptomatic meningiomas represents a challenge due to the absence of a solid consensus on which is the best management strategy. There are various known factors predicting meningiomas growth risk. However, the Asian Intracranial Meningioma Scoring System (AIMSS) is the only described score to quantify such risk thus emerging as a potential tool for management decisions. This study aims to validate this score on our series of asymptomatic meningiomas.

METHOD

We performed a retrospective review of asymptomatic meningiomas diagnosed at our institution between January 2008 and October 2016 and followed by an annual cerebral Magnetic Resonance Imaging (MRI). For each lesion, the AIMSS score was calculated thus classifying them in low (0-2), intermediate (3-6) or high risk (7-11) of rapid growth (>2cm³/year). We investigated the correlation between the expected Average Growth Rate (AGR) according to the score and the one obtained in our study. The mean growth velocity over the different risk groups was also compared.

RESULTS

Overall, 69 asymptomatic meningiomas found incidentally in 46 patients were included in the study; 31 were assigned to the low-risk group, 34 to the intermediate-risk group and 4 to the high-risk group. Attending to the AGR, 0% showed rapid growth in the low-risk group, 12% in the intermediate-risk group, and 25% in the high-risk group. The mean growth velocity showed a significant difference over the different risk groups (p < 0,001).

CONCLUSIONS

According to our finding, the AIMSS score is a valid tool to estimate the risk of rapid growth of asymptomatic meningiomas. It is especially useful distinguishing between low- and intermediate-risk meningiomas. This feature would allow physicians to adjust the periodicity of radiological and clinical controls. Adding more known risk factors of rapid growth to the score might improve its predictive capabilities with the high-risk group.

Comparison of ABC/2 estimation and a volumetric computerized method for measurement of meningiomas using magnetic resonance imaging

INTRODUCTION

Measurement of tumor growth rates over time for patients with meningiomas has important prognostic and therapeutic implications. Our objective was to compare two methods of measuring meningioma volume: (1) the simplified ellipsoid (ABC/2) method; and (2) perimetric volume measurements using imaging software modules.

METHODS

Patients with conservatively managed meningiomas for at least 1.5 years were retrospectively identified from the VCU Brain and Spine Tumor Registry over a 10-year period (2005-2015). Tumor volumes were independently measured using the simplified ellipsoid and computerized perimetric methods. Intra class correlations (CC) and Bland-Altman analyses were performed.

RESULTS

A total of 26 patients representing 29 tumors were identified. Across 146 images, there were 24 (16%) images that were non-measurable using standard application commands with the computerized perimetric method. The mean volume obtained using the ABC/2 and computerized perimetric methods were 3.2 ± 3.4 cm³ and 3.4 ± 3.5 cm³, respectively. The mean volume difference was 0.2 cm³ (SE = 0.12; p = 0.10) across measurement methods. The concordance correlation coefficient (CCC) between methods was 0.95 (95% CI 0.91, 0.98).

CONCLUSIONS

There is excellent correlation between the simplified ellipsoid and computerized perimetric methods of volumetric analysis for conservatively managed meningiomas. The simplified ellipsoid method remains an excellent method for meningioma volume assessment and had an advantage over the perimetric method which failed to allow measurement of roughly one in six tumors on imaging.

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.

Intraoperative quantification of meningioma cell proliferation potential using rapid flow cytometry reveals intratumoral heterogeneity

Background

Standard sampling methods to evaluate the proliferative ability of meningioma have not been established.

Methods

This prospective study was conducted to evaluate the effectiveness of intraoperative rapid flow cytometry (iFC) using raw samples for the quantitative assessment of proliferative ability in meningioma cells and to investigate intratumoral heterogeneity. Proliferation index (PI) was defined as the ratio of aneuploid cells with an abnormal number of chromosomes to the total cells.

Results

From 50 patients, 118 specimens were analyzed. There was a statistically significant correlation between the postoperative MIB‐1 labeling index (LI) and PI (R = 0.59, P < 0.0001). A higher PI was correlated with a higher annual growth rate (AGR, cm³/y) (R = 0.50, P = 0.0002, 26 patients). AGR showed a correlation with the intratumoral distribution of PI. PI was the highest at the center or the peripheral section of the tumor in tumors with high AGR, whereas it was highest at the dural attachment in tumors with low AGR (P = 0.039, n = 20). Pial feeders were more frequently observed when PI was high in the center or in the peripheral section (P = 0.006, n = 37).

Conclusions

Rapid iFC may thus become a substitute for MIB‐1 LI. Intratumoral heterogeneity of cellular proliferative potential exists in meningiomas and is related to tumor biological characteristics such as AGR and development of pial feeders. This observation underscores the importance of standardization in the sampling method to accurately estimate the risk of meningioma recurrence.

CORRELATION OF PERITUMORAL BRAIN EDEMA WITH MORPHOLOGICAL CHARACTERISTICS AND KI67 PROLIFERATIVE INDEX IN RESECTED INTRACRANIAL MENINGIOMAS

The aim of the study was to analyze correlation between morphological characteristics of intracranial meningiomas and Ki67 labeling index (Ki67 LI), and their influence on peritumoral brain edema (PTBE). There were 41 consecutive patients with intracranial meningiomas surgically treated at the Department of Neurosurgery, Zenica Cantonal Hospital, Zenica, Bosnia and Herzegovina, during the period from January 2010 to December 2015. We reviewed clinical data including patient age, gender, magnetic resonance imaging (MRI) characteristics of the tumor and peritumoral edema, tumor margins, intraoperative characteristics, histopathologic grade and Ki67 LI. In all cases, follow up MRI was obtained at about three months after resection and PTBE was analyzed. Our research showed the tumor volume, tumor margins, and intraoperative signs of arachnoidal and pial invasion to be associated with PTBE in intracranial meningiomas. Ki67 LI expression correlated with PTBE. This study showed the resolution of PTBE to depend on invasive behavior of meningioma and KI67 LI. PTBE, pial/cortical and arachnoidal invasion significantly influence the extent of surgical resection.

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.

Skull base versus non-skull base meningioma surgery in the elderly

To compare outcomes after surgery for skull base meningiomas (SBMs) with non-skull base meningiomas (NSBMs) in the elderly. Overall, 128 consecutive patients ≥ 70 years of age with intracranial SBMs operated between 1990 and 2010 were compared to 193 consecutive patients ≥ 70 years of age with NSBMs operated within the same time period. Median age at surgery was 75.0 years (mean 75.7, range 70.0-92.4). Follow-up was complete with median 4.7 years (mean 5.5, range 0-19). The female-to-male ratio was 2.8 for SBMs and 1.3 for NSBMs (p < 0.005). The groups had similar preoperative KPS (median 80, range 20-100), but SBMs presented significantly more frequently with raised ICP (RR = 2.2, p < 0.005) and less frequently with seizures (RR = 0.6, p < 0.05). WHO I was significantly more frequent in SBMs (p < 0.005). Gross-total resection (GTR) was less frequent in SBMs (63 vs 82%) (RR = 2.1, p < 0.0001). SBMs were similar to NSBMs with respect to neurological outcome at 6-12 months, reoperations for hematomas, postoperative infections, and 30-day mortality. Retreatment rates and time to retreatments were also similar. There were no differences between the two groups with respect to risk of retreatment and overall survival (OS) at 5, 10, 15, and 20 years. In elderly patients with SBMs selected to surgical treatment, the risks of surgery, risk of retreatment, and OS were similar to NBSMs. Therefore, surgery for SBMs may be considered as safe as NSBMs in the elderly population.

Fractal Analysis May Improve the Preoperative Identification of Atypical Meningiomas

Background

There is no objective and readily accessible method for the preoperative determination of atypical characteristics of a meningioma grade.

Objective

To evaluate the feasibility of using fractal analysis as an adjunctive tool to conventional radiological techniques in visualizing histopathological features of meningiomas.

Methods

A group of 27 patients diagnosed with atypical (WHO grade II) meningioma and a second group of 27 patients with benign (WHO grade I) meningioma were enrolled in the study. Preoperative brain magnetic resonance (MR) studies (T1-wieghted, post-gadolinium) were processed and analyzed to determine the average fractal dimension (FDa) and maximum fractal dimension (FDm) of the contrast-enhancing region of the tumor using box-count method. FDa and FDm as well as particular radiological features were included in the logistic regression model as possible predictors of malignancy.

Results

The cohort consisted of 34 women and 20 men, mean age of 62 ± 15 yr. Fractal analysis showed good interobserver reproducibility (Kappa >0.70). Both FDa and FDm were significantly higher in the atypical compared to the benign meningioma group (P < .0001). Multivariate logistic regression model reached statistical significance with P = .0001 and AUC = 0.87. The FDm, which was greater than 1.31 (odds ratio [OR], 12.30; P = .039), and nonskull base localization (OR, .052; P = .015) were confirmed to be statistically significant predictors of the atypical phenotype.

Conclusion

Fractal analysis of preoperative MR images appears to be a feasible adjunctive diagnostic tool in identifying meningiomas with potentially aggressive clinical behavior.

Meningiomas: skull base versus non-skull base

To identify differences between skull base meningiomas (SBM) and non-skull base meningiomas (NSBM). All adult patients (18.0-69.9 years) operated for intracranial meningiomas between 1990 and 2010 at our institution were investigated. Al-Mefty's definition was used to dichotomize tumors into SBM and NSBM. Overall, 1148 consecutive patients were identified. Median age at surgery was 54.2 years [18.1-69.9]. Median follow-up was 7.4 years [0.0-20.9]. There were 562 patients (49%) with SBM and 586 (51%) with NSBM. The two groups were similar with respect to patient age, follow-up time, and number of patients. Overall female-to-male ratio was 2.6:1, but 3.2:1 in SBM and 2.2:1 in NSBM (p < 0.005). With respect to presenting symptoms, SBMs had more often neurological deficits (risk ratio (RR) 1.4; p < 0.0001) and less often seizures (RR 0.4; p < 0.0001). Gross total resections were less frequent in SBM than NSBM (62 vs 84%) (RR 1.3; p < 0.0001). SBMs had a lower risk of WHO grades II and III histology (4.5 vs 9.5%) (RR 0.5; p < 0.001). Worsening of neurological function was more frequent in SBM (21 vs 121%) (RR 1.8; p < 0.001). Retreatment-free survival at 5, 10, and 15 years, respectively, was 80, 70, and 62% for SBM versus 90, 82, and 74% for NSBM (p < 0.0001). Overall survival at 5, 10, and 15 years, respectively, was 93, 85, and 78% for SBM and 96, 91, and 79% for NSBM (p = 0.14). Patients with SBMs had more new-onset neurological deficits and significantly shorter retreatment-free survivals, but this did not adversely affect the overall survival.

Meningioma Consistency: Correlation Between Magnetic Resonance Imaging Characteristics, Operative Findings, and Histopathological Features

INTRODUCTION

Intracranial meningiomas account for 30% of all primary intracranial tumors. Surgical resection remains the mainstay of the treatment for meningiomas. The magnetic resonance of intracranial meningiomas has been largely discussed in many reports of the radiological and neurosurgical literature. To date, a few studies have been attempted to differentiate the tumor characteristics of meningiomas based on magnetic resonance imaging (MRI) studies.

OBJECTIVE

The objective of the study is to evaluate the relationship between MRI signal characteristics of intracranial meningiomas and consistency of tumor using objective measures.

MATERIALS AND METHODS

A prospective study included all the patients who were admitted for surgery with an MRI finding suggestive of meningioma. All patients were subjected to routine radiological investigations. Surgical resection was performed for patients eligible for surgery using cavitron ultrasonic aspirator (CUSA). The relationship and correlation between the radiological, intraoperative measurements and the histopathological diagnosis were studied. The tumor consistency was measured using mean CUSA level. Intensity on T2, fluid-attenuated inversion recovery (FLAIR), and diffusion-weighted imaging (DWI) was measured using circular regions of interest (ROI) on the MRI. Multiple ROIs were placed initially on the lesions avoiding the obvious blood vessels, if any, then on the brain cortex to avoid the vasogenic edema. The mean ROI (mROI) results from the lesion were subtracted from the mean ROI from the brain cortex for each lesion to achieve normalized ratio. The results of lesion mROI-cortex mROI were compared to the operative and histopathology results using Pearson's correlation test and linear regression test.

RESULTS

The total number of patients was seventy. The mean age of the patients was 51 ± 14.8, with 72% of them being females and 28% males. There was a strong statistically significant (P = 0.046) and (P = 0.003) correlation between mean CUSA and FLAIR mROI difference or T2 mROI difference, respectively. On the other hand, there was an inversely proportional relationship between mean CUSA and FLAIR mROI difference and mean CUSA and T2 mROI difference. The value of the regression test (r) shows that there was a slight linear relationship between FLAIR mROI difference or T2 mROI difference and mean CUSA values, in which the mean CUSA value = 50.1 + (-0.088) × FLAIR mROI difference (r = -0.273, P = 0.046) or mean CUSA value = 50.8 + (-0.055) × T2 mROI difference (r = 0.4, P = 0.003). There was no statistical significance in the relation between CUSA values and tumor histological subtypes, DWI values, age, or gender.

CONCLUSION

This study presents a new objective method to measure the consistency of intracranial meningiomas based on a simple algorithmic formula. Such information will aid in planning surgery and assessing the resectability of the tumor. To date, this is the first objective measurement of meningioma consistency based on MRI studies and objective intraoperative evaluation.

Prognostic factors for olfactory groove meningioma with nasal cavity extension

Objectives

Meningioma recurrence remains a significant issue. No study has described the relationship between the clinical features and prognosis of communicating meningioma that primarily originates from the olfactory groove. The aim of the study was to identify prognostic factors of communicating olfactory groove meningiomas that could be stratified according to their risk of recurrence.

Results

A Simpson grade one or two resection was achieved. Complications with cerebrospinal rhinorrhoea occurred in two patients: one required reoperation, and the other was managed successfully with external drainage of lumbar cistern. There were 5 known clinical recurrences within the median follow-up of more than 5 years. The median 5-year recurrence-free survival for patients was 88.4%. Factors such as gender, tumour size, T2 signal and the hyperostotic bone had no significant effect on recurrence-free survival. However, recurrence was activated by oedema range, hyperostosis, dural tail sign and tumor texture (p < 0.05). Interestingly, female patients with the disease were younger than males at diagnosis, and the difference was statistically significant ( p = 0.013).

Conclusions

Based on these features of communicating olfactory groove meningiomas, different strategies may be adopted for the follow-up and subsequent treatment. Due to the relatively uncommon incidence, more investigations into the clinical behaviour of this entity are crucial.

Patients and Methods

A retrospective study of 43 patients harbouring olfactory groove meningiomas invading the ethmoid or nasal cavity was conducted at three medical centers from 2000 to 2010. The records were reviewed for clinical presentations, imaging studies, surgical observation, histological features and follow-up.

Differentiating meningioma grade by imaging features on magnetic resonance imaging

Atypical meningioma has an aggressive clinical course. Distinguishing atypical from benign meningioma preoperatively could affect surgical planning and improve treatment outcomes. In this study, we examined whether pre-operative magnetic resonance imaging (MRI) features could distinguish between benign and atypical meningioma. Imaging factors analyzed included peritumoral edema, the presence of a draining vein, tumor necrosis, tumor location and tumor volume. Using univariate analysis, the most striking predictor of grade was tumor volume (p < .001). When adjusting for the degree of peritumoral edema, volume remained a positive predictor of higher histological grade meningioma (p = .042) and was the strongest single predictor of higher-grade meningioma in this study. Additional imaging features associated with increased risk for atypical pathology in univariate analysis included the presence of tumor necrosis (p = .012), peritumoral edema (p = .022) and location along the falx and convexity (p = .026). Despite statistically significant associations using univariate analysis, in multivariate analysis, we found that only presence of peritumoral edema was predictive of a higher-grade meningioma. Further multivariate analyses suggests that edema, draining vein and necrosis are all positive predictors of tumor volume (p < .0001). Overall, these data suggest that radiographic features including presence of tumor necrosis, and tumor location along the falx or convexity may be predictive of higher-grade meningioma when considered alone. However, most strikingly, our data point to tumor volume as the most robust pre-operative indicator of higher-grade meningioma.

A novel weighted scoring system for estimating the risk of rapid growth in untreated intracranial meningiomas

OBJECTIVE

Advances in neuroimaging techniques have led to the increased detection of asymptomatic intracranial meningiomas (IMs). Despite several studies on the natural history of IMs, a comprehensive evaluation method for estimating the growth potential of these tumors, based on the relative weight of each risk factor, has not been developed. The aim of this study was to develop a weighted scoring system that estimates the risk of rapid tumor growth to aid treatment decision making.

METHODS

The authors performed a retrospective analysis of 232 patients with presumed IM who had been prospectively followed up in the absence of treatment from 1997 to 2013. Tumor volume was measured by imaging at each follow-up visit, and the growth rate was determined by regression analysis. Predictors of rapid tumor growth (defined as ≥ 2 cm3/year) were identified using a logistic regression model; each factor was awarded a score based on its own coefficient value. The probability (P) of rapid tumor growth was estimated using the following formula:

RESULTS

Fifty-nine tumors (25.4%) showed rapid growth. Tumor size (OR per cm3 1.07, p = 0.000), absence of calcification (OR 3.87, p = 0.004), peritumoral edema (OR 2.74, p = 0.025), and hyperintense or isointense signal on T2-weighted MRI (OR 3.76, p = 0.049) were predictors of tumor growth rate. In the Asan Intracranial Meningioma Scoring System (AIMSS), tumor size was categorized into 3 groups of < 2.5 cm, ≥ 2.5 to < 4.0 cm, and ≥ 4.0 cm in diameter and awarded a score of 0, 3, and 6, respectively; the parameters of calcification and peritumoral edema were categorized into 2 groups based on their presence or absence and given a score of 0 or 2 and 1 or 0, respectively; and the signal on T2-weighted MRI was categorized into 2 groups of hypointense and hyperintense/isointense and given a score of 0 or 2, respectively. The risk of rapid tumor growth was estimated to be < 10% when the total score was 0–2, 10%–50% when the total score was 3–6, and ≥ 50% when the total score was 7–11 (Hosmer-Lemeshow goodness-of-fit test, p = 0.9958). The area under the receiver operating characteristic curve was 0.86.

CONCLUSIONS

The authors suggest a weighted scoring system (AIMSS) that predicts the specific probability of rapid tumor growth for patients with untreated IM. This scoring system will aid treatment decision making in clinical settings by screening out patients at high risk for rapid tumor growth.