Multimodal Brain Tumor Classification Using Convolutional Tumnet Architecture.

The most common and aggressive tumor is brain malignancy, which has a short life span in the fourth grade of the disease. As a result, the medical plan may be a crucial step toward improving the well-being of a patient. Both diagnosis and therapy are part of the medical plan. Brain tumors are commonly imaged with magnetic resonance imaging (MRI), positron emission tomography (PET), and computed tomography (CT). In this paper, multimodal fused imaging with classification and segmentation for brain tumors was proposed using the deep learning method. The MRI and CT brain tumor images of the same slices (308 slices of meningioma and sarcoma) are combined using three different types of pixel-level fusion methods. The presence/absence of a tumor is classified using the proposed Tumnet technique, and the tumor area is found accordingly. In the other case, Tumnet is also applied for single-modal MRI/CT (561 image slices) for classification. The proposed Tumnet was modeled with 5 convolutional layers, 3 pooling layers with ReLU activation function, and 3 fully connected layers. The first-order statistical fusion metrics for an average method of MRI-CT images are obtained as SSIM tissue at 83%, SSIM bone at 84%, accuracy at 90%, sensitivity at 96%, and specificity at 95%, and the second-order statistical fusion metrics are obtained as the standard deviation of fused images at 79% and entropy at 0.99. The entropy value confirms the presence of additional features in the fused image. The proposed Tumnet yields a sensitivity of 96%, an accuracy of 98%, a specificity of 99%, normalized values of the mean of 0.75, a standard deviation of 0.4, a variance of 0.16, and an entropy of 0.90.

Clinical implications of DNA methylation-based integrated classification of histologically defined grade 2 meningiomas.

The combination of DNA methylation analysis with histopathological and genetic features allows for a more accurate risk stratification and classification of meningiomas. Nevertheless, the implications of this classification for patients with grade 2 meningiomas, a particularly heterogeneous tumor entity, are only partially understood. We correlate the outcomes of histopathologically confirmed grade 2 meningioma with an integrated molecular-morphologic risk stratification and determine its clinical implications. Grade 2 meningioma patients treated at our institution were re-classified using an integrated risk stratification involving DNA methylation array-based data, copy number assessment and TERT promoter mutation analyses. Grade 2 meningioma cases according to the WHO 2021 criteria treated between 2007 and 2021 (n = 100) were retrospectively analyzed. The median clinical and radiographic follow-up periods were 59.8 and 54.4 months. A total of 38 recurrences and 17 deaths were observed. The local control rates of the entire cohort after 2-, 4-, and 6-years were 84.3%, 68.5%, and 50.8%, with a median local control time of 77.2 months. The distribution of the integrated risk groups were as follows: 31 low, 54 intermediate, and 15 high risk cases. In the multivariable Cox regression analysis, integrated risk groups were significantly associated with the risk of local recurrence (hazard ratio (HR) intermediate: 9.91, HR high-risk: 7.29, p < 0.01). Gross total resections decreased the risk of local tumor progression (HR gross total resection: 0.19, p < 0.01). The comparison of 1p status and integrated risk groups (low vs. intermediate/high) revealed nearly identical local control rates within their respective subgroups. In summary, only around 50% of WHO 2021 grade 2 meningiomas have an intermediate risk profile. Integrated molecular risk stratification is crucial to guide the management of patients with grade 2 tumors and should be routinely applied to avoid over- and undertreatment, especially concerning the use of adjuvant radiotherapy.

Leveraging single-cell sequencing to classify and characterize tumor subgroups in bulk RNA-sequencing data.

PURPOSE: Accurate classification of cancer subgroups is essential for precision medicine, tailoring treatments to individual patients based on their cancer subtypes. In recent years, advances in high-throughput sequencing technologies have enabled the generation of large-scale transcriptomic data from cancer samples. These data have provided opportunities for developing computational methods that can improve cancer subtyping and enable better personalized treatment strategies. METHODS: Here in this study, we evaluated different feature selection schemes in the context of meningioma classification. To integrate interpretable features from the bulk (n = 77 samples) and single-cell profiling (∼ 10 K cells), we developed an algorithm named CLIPPR which combines the top-performing single-cell models, RNA-inferred copy number variation (CNV) signals, and the initial bulk model to create a meta-model. RESULTS: While the scheme relying solely on bulk transcriptomic data showed good classification accuracy, it exhibited confusion between malignant and benign molecular classes in approximately ∼ 8% of meningioma samples. In contrast, models trained on features learned from meningioma single-cell data accurately resolved the sub-groups confused by bulk-transcriptomic data but showed limited overall accuracy. CLIPPR showed superior overall accuracy and resolved benign-malignant confusion as validated on n = 789 bulk meningioma samples gathered from multiple institutions. Finally, we showed the generalizability of our algorithm using our in-house single-cell (∼ 200 K cells) and bulk TCGA glioma data (n = 711 samples). CONCLUSION: Overall, our algorithm CLIPPR synergizes the resolution of single-cell data with the depth of bulk sequencing and enables improved cancer sub-group diagnoses and insights into their biology.

Role of adjuvant radiotherapy in atypical (WHO grade II) and anaplastic (WHO grade III) meningiomas: a systematic review

The systematic adoption of the histopathologic criteria provided by the 2016 update of the WHO classification of brain tumors has markedly increased the relative proportion of atypical and anaplastic meningiomas. These tumors exhibit a much greater recurrence rate compared to benign meningiomas, which negatively impacts survival. In recent years, the publication of numerous retrospective case series, yet no randomized controlled trials, on the impact of radiation therapy in non-benign meningioma, has yielded conflicting evidence. At present, maximum safe resection, including the dural attachment, is the preferred primary treatment modality for all types of meningiomas. Adjuvant radiotherapy is currently recommended for subtotally resected grade II and for all grade III meningiomas. However, in grade II meningiomas achieving complete resection, close radiologic and clinical observation is a feasible option. Despite the great amount of non-benign meningiomas available and eligible for trials, there is a striking lack of prospective studies testing adjuvant therapies against observation for this subset of patients. An updated and systematic literature review is provided on the effectiveness and indications of radiotherapy on grade II and III meningiomas (AU)

Novel histopathological classification of meningiomas based on dural invasion.

AIMS: Histological invasion into the adjacent brain parenchyma is frequently investigated in meningioma because it is an important morphological criterion for grade II meningioma according to the 2016 WHO classification. However, few studies have focused on dural invasion of meningiomas. Herein, we propose a novel histopathological classification based on dural invasion of meningiomas. METHODS: Forty-nine cases with WHO grade I meningiomas who underwent Simpson grade I removal were collected. After the meningeal layer (ML) and periosteal layer (PL) of dura mater were visualised by Masson's trichrome stain, we evaluated the depth (to the ML and PL) and the patterns (1, expanding; 2, infiltrating) of dural invasion of meningiomas using serial paraffin sections. Invasion-associated markers, including Ki-67, matrix metalloproteinase (MMP)-1, MMP-9 and MMP-13, aquaporin 1 and Na-K-2Cl cotransporter, were quantitatively analysed by immunohistochemistry. RESULTS: Thirty-five cases (71.4%) showed the dural invasion. In 27 of these 35 cases (77.1%), dural invasion was localised in ML. Type 1 (expanding type) and type 2 (infiltrating type) invasions were observed in 23 and 12 cases, respectively. The recurrence rate in cases with type 2 invasion was significantly higher than that in cases with type 1 invasion. The percentage of MMP-1-positive tumour cells was also significantly higher in cases with dural invasion than those without, suggesting involvement of MMP-1 in dural invasion. CONCLUSIONS: We quantitatively evaluated the depth and patterns of dural invasion in meningiomas. The patterns of dural invasion were associated with meningioma recurrence.

WHO classification of meningiomas-A single institutional experience.

INTRODUCTION: Meningiomas are among the most common intracranial neoplasms worldwide. The World Health Organization (WHO) has classified the neoplasm into three grades with each grade having several histological variants. Several studies done in blacks have shown differences with Caucasian populations regarding the occurrence of histological variants. Our study sought to examine the histological variants of meningioma seen in a predominantly black population using the WHO grading system. METHODS: We conducted a retrospective study of all meningiomas seen in our hospital facility for over twenty years. An analysis of data from all the patients diagnosed with meningioma, who also had surgical biopsies taken, was done. The meningiomas were graded using the WHO grading system and also classified into different histological variants within each grade as described by the WHO study group. RESULTS: The study included a total number of 163 biopsies. There were more females diagnosed with meningiomas with a female to male ratio of 1.4. Most of the tumors were grade one, however, there were more males with malignant meningiomas. Transitional meningiomas were the most commonly seen variants among the grade one tumors while atypical and anaplastic were most common in grades two and three, respectively. CONCLUSION: A larger population-based study is needed to provide epidemiological data on the occurrence of meningiomas in blacks.

Role of adjuvant radiotherapy in atypical (WHO grade II) and anaplastic (WHO grade III) meningiomas: a systematic review.

The systematic adoption of the histopathologic criteria provided by the 2016 update of the WHO classification of brain tumors has markedly increased the relative proportion of atypical and anaplastic meningiomas. These tumors exhibit a much greater recurrence rate compared to benign meningiomas, which negatively impacts survival. In recent years, the publication of numerous retrospective case series, yet no randomized controlled trials, on the impact of radiation therapy in non-benign meningioma, has yielded conflicting evidence. At present, maximum safe resection, including the dural attachment, is the preferred primary treatment modality for all types of meningiomas. Adjuvant radiotherapy is currently recommended for subtotally resected grade II and for all grade III meningiomas. However, in grade II meningiomas achieving complete resection, close radiologic and clinical observation is a feasible option. Despite the great amount of non-benign meningiomas available and eligible for trials, there is a striking lack of prospective studies testing adjuvant therapies against observation for this subset of patients. An updated and systematic literature review is provided on the effectiveness and indications of radiotherapy on grade II and III meningiomas.

Distinct genomic subclasses of high-grade/progressive meningiomas: NF2-associated, NF2-exclusive, and NF2-agnostic.

BACKGROUND: Genomic studies of high-grade/progressive meningiomas have reported a heterogeneous mutation spectrum, identifying few recurrently mutated genes. Most studies have been underpowered to detect genomic subclasses of aggressive meningiomas due to relatively small number of available samples. Here, we present a genomic survey of one of the largest multi-institutional cohorts of high-grade/progressive meningiomas to date. METHODS: 850 high-grade/progressive meningiomas, including 441 WHO grade 2 and 176 WHO grade 3 meningiomas and 220 progressive WHO grade 1 meningiomas, were tested as part of a clinical testing program by hybridization capture of 406 cancer-related genes to detect base substitutions, indels, amplifications, deletions, and rearrangements. Information from pathology reports, histopathology review, and patient clinical data was assessed. RESULTS: Genomic analyses converged to identify at least three distinct patterns of biologically-aggressive meningiomas. The first and most common contained NF2-mutant tumors (n = 426, 50%), was associated with male sex (64.4% %, p = 0.0001) and often harbored additional mutations in CDKN2A/B (24%), and the chromatin regulators ARID1A (9%), and KDM6A (6%). A second group (NF2-agnostic) featured TERT promoter (TERTp; n = 56) or TP53 mutations (n = 25) and were either NF2-mutant or wild-type, and displayed no association with either sex (p = 0.39). The remaining group generally lacked NF2 mutations, and accounted for 40% of the cases-with three subgroups. One consistent primarily of grade 3 lesions harboring alterations in chromatin regulators BAP1 (n = 22) or PBRM1 (n = 16). A second subgroup contained AKT1 (n = 26), PIK3CA (n = 14) and SMO (n = 7) mutant skull-based meningiomas, and a third mixed subgroup included 237 meningiomas with a heterogeneous spectrum of low frequency and non-recurrent alterations. CONCLUSIONS: Our findings indicate that the patterns of genomic alterations in high-grade/progressive meningiomas commonly group into three different categories. The most common NF2-associated canonical group frequently harbored CDKN2A/B alterations, which is potentially amenable to targeted therapies. An NF2-agnostic group harbored frequent TERTp and TP53 mutations. The final subclass, distinct from the canonical NF2 mutant associated pathway, was partly characterized by BAP1/PBRM1 alterations (rhabdoid/papillary histology) or skull-base disease. Overall, these data increase our understanding of the pathobiology of high-grade/progressive meningiomas and can guide the design of clinical trials. IRB APPROVAL STATUS: Reviewed and approved by Western IRB; Protocol No. 20152817.

Advances in Molecular Classification and Therapeutic Opportunities in Meningiomas.

PURPOSE OF REVIEW: Our understanding of the genetic and epigenetic alterations in meningioma and the underlying tumor biology of meningioma has significantly changed over the past decade and resulted in revision of prognostically relevant meningioma subclasses within and beyond the WHO classification of CNS tumors. RECENT FINDINGS: The 2016 WHO classification of CNS tumors recognizes WHO grade I, II, and III based on histopathological features. Recent work has identified genetic alterations with prognostic implications, including mutations of the TERT promoter, loss of function of the DMD gene, and inactivation of the tumor suppressor BAP-1. Studies of DNA methylation patterns in meningiomas have resulted in a novel and prognostically relevant meningioma subclassification schema. There have been major advances in our understanding of prognostically relevant genetic and epigenetic changes in meningioma which will hopefully allow for improvement in clinical trial design and the development of more effective therapies for meningioma.

Cyclin E1 expression and malignancy in meningiomas.

OBJECTIVE: The aim of the present study was to analyze if the pathway Skp2-p27-cyclin E1 could also be a tumor progression marker for meningiomas. PATIENTS AND METHODS: We used quantitative real-time PCR to assess the relative expression levels of the genes coding for cyclin E1 (CCNE1), Skp2 (SKP2), and p27 (P27). The expression levels were compared in grades I to III meningiomas and among different histological subtypes of grade I meningiomas. RESULTS: Anaplastic meningiomas accounted for 4.9%, atypical meningiomas for 23.5% and grade I meningiomas for 71.6%.CCNE1 expression level was significantly higher in grade II compared to grade I meningiomas (p = 0.0027), and its expression level reliably predicts grade II meningiomas (ROC AUC = 0.731, p = 0.003). CCNE1 expression also correlated with SKP2 and P27 expression levels in grade I meningiomas (r = 0.539, p < 0.0001 and r = 0.687, p = <0.0001, respectively for CCNE1/SKP2 and CCNE1/P27, Spearman's test). Fibrous subtype among grade I meningiomas presented the highest expression levels of CCNE1, SKP2 and P27. Higher expression of cyclin E1 protein was detected in the nuclei of atypical meningiomas compared to grade I meningiomas. CONCLUSIONS: CCNE1 expression level predicts meningioma malignancy, and the fibrous subtype presents the highest gene expression levels among grade I meningiomas.

WHO grade I meningiomas: classification-tree for prognostic factors of survival.

World Health Organization (WHO) grade I meningiomas are intracranial extracerebral tumors, in which microsurgery as a stand-alone therapy provides high rates of disease control and low recurrence rates. Our aim was to identify prognostic factors of overall survival and time-to-retreat (OS; TTR) in a cohort of patients with surgically managed WHO grade I meningioma. Patients with WHO grade I meningiomas from a retrospectively (1990 to 2002) and prospectively managed (2003 to 2010) databank of Oslo University Hospital, Norway, were included. The mean follow-up was 9.2 ± 5.7 years, with a total of 11,414 patient-years. One thousand three hundred fifty-five patients were included. The mean age was 58 ± 13.2, mean Karnofsky Performance Status (KPS) 92.6 ± 26.1 and female-to-male ratio 2.5:1. The 1-year, 5-year, 10-year, 15-year, and 20-year probabilities were 0.98, 0.91, 0.87, 0.84, and 0.8 for TTR. Patient age (OR 0.92 [0.91, 0.94]), male sex (OR 0.59 [0.45, 0.76]), preoperative KPS ≥ 70 (OR 2.22 [1.59, 3.13]), skull base location (OR 0.77 [0.60, 1]), and the occurrence of a postoperative hematoma (OR 0.44 [0.26, 0.76]) were identified as independent prognostic factors of OS. Patient age (OR 1.02 [1.01, 1.03]) and skull base location (OR 0.30 [0.21, 0.45]) were independent predictors of decreased PFS. Using a recursive partitioning analysis, we suggest a classification tree for the prediction of 5-year PFS based on patient and tumor characteristics. The findings from this cohort of meningioma WHO I patients helps to identify patients at risk of recurrence and tailor the therapeutic management.

Intracranial Metastases from Prostate Carcinoma: Classification, Management, and Prognostication.

BACKGROUND: Prostate carcinomas rarely metastasize to the central nervous system but, when they do, dural localizations are as common as and far more aggressive than intraparenchymal ones. Those metastases can be further classified according to their extension toward the subdural or extradural space and can frequently simulate other pathologic conditions including chronic subdural hematomas, abscess, and primary bone tumors. Beside the challenges of the preoperative differential diagnostic and complexity of surgical planning and operative excision, subdural metastases seem to carry a much poorer prognosis. METHODS: A series of consecutive patients admitted during a 12-year period through our oncall pathway for subdural/extradural collections or intraparenchymal lesions found, on histologic analysis, to represent intracranial prostate cancer metastases was retrospectively reviewed. RESULTS: A total of 19 patients were included, but only 3 were diagnosed with small cell prostate carcinoma, while the majority had a primary prostate adenocarcinoma. Metastases could be classified as pure subdural space lesions, dural-based lesions, extradural/bony lesions, and pure intraparenchymal lesions. All patients with subdural metastases and 3 out of 5 patients with dural-based lesions required an emergency intervention due to rapidly deteriorating neurologic status. The mean follow-up in our series was 37 months; only subdural localizations had a remarkably unfavorable outcome. CONCLUSIONS: Supported by our experience and the review of the literature, we suggest that a low threshold for contrast-enhanced computed tomography/magnetic resonance imaging is advisable in case of suspicious subdural collection, even in an emergency setting, for patients with previous medical history of prostate cancer.

A prognostic model to personalize monitoring regimes for patients with incidental asymptomatic meningiomas.

BACKGROUND: Asymptomatic meningioma is a common incidental finding with no consensus on the optimal management strategy. We aimed to develop a prognostic model to guide personalized monitoring of incidental meningioma patients. METHODS: A prognostic model of disease progression was developed in a retrospective cohort (2007-2015), defined as: symptom development, meningioma-specific mortality, meningioma growth or loss of window of curability. Secondary endpoints included non-meningioma-specific mortality and intervention. RESULTS: Included were 441 patients (459 meningiomas). Over a median of 55 months (interquartile range, 37-80), 44 patients had meningioma progression and 57 died (non-meningioma-specific). Forty-four had intervention (at presentation, n = 6; progression, n = 20; nonprogression, n = 18). Model parameters were based on statistical and clinical considerations and included: increasing meningioma volume (hazard ratio [HR] 2.17; 95% CI: 1.53-3.09), meningioma hyperintensity (HR 10.6; 95% CI: 5.39-21.0), peritumoral signal change (HR 1.58; 95% CI: 0.65-3.85), and proximity to critical neurovascular structures (HR 1.38; 95% CI: 0.74-2.56). Patients were stratified based on these imaging parameters into low-, medium- and high-risk groups and 5-year disease progression rates were 3%, 28%, and 75%, respectively. After 5 years of follow-up, the risk of disease progression plateaued in all groups. Patients with an age-adjusted Charlson comorbidity index ≥6 (eg, an 80-year-old with chronic kidney disease) were 15 times more likely to die of other causes than to receive intervention at 5 years following diagnosis, regardless of risk group. CONCLUSIONS: The model shows that there is little benefit to rigorous monitoring in low-risk and older patients with comorbidities. Risk-stratified follow-up has the potential to reduce patient anxiety and associated health care costs.

Determination of meningioma brain tumour grades using Raman microspectroscopy imaging.

Raman spectroscopy is a powerful technique used to analyse biological materials, where spectral markers such as proteins (1500-1700 cm-1), carbohydrates (470-1200 cm-1) and phosphate groups of DNA (980, 1080-1240 cm-1) can be detected in a complex biological medium. Herein, Raman microspectroscopy imaging was used to investigate 90 brain tissue samples in order to differentiate meningioma Grade I and Grade II samples, which are the commonest types of brain tumour. Several classification algorithms using feature extraction and selection methods were tested, in which the best classification performances were achieved by principal component analysis-quadratic discriminant analysis (PCA-QDA) and successive projections algorithm-quadratic discriminant analysis (SPA-QDA), resulting in accuracies of 96.2%, sensitivities of 85.7% and specificities of 100% using both methods. A biochemical profiling in terms of spectral markers was investigated using the difference-between-mean (DBM) spectrum, PCA loadings, SPA-QDA selected wavenumbers, and the recovered imaging profiles after multivariate curve resolution alternating least squares (MCR-ALS), where the following wavenumbers were found to be associated with class differentiation: 850 cm-1 (amino acids or polysaccharides), 1130 cm-1 (phospholipid structural changes), the region between 1230-1360 cm-1 (Amide III and CH2 deformation), 1450 cm-1 (CH2 bending), and 1858 cm-1 (C[double bond, length as m-dash]O stretching). These findings highlight the potential of Raman microspectroscopy imaging for determination of meningioma tumour grades.

Mutational patterns and regulatory networks in epigenetic subgroups of meningioma.

DNA methylation patterns delineate clinically relevant subgroups of meningioma. We previously established the six meningioma methylation classes (MC) benign 1-3, intermediate A and B, and malignant. Here, we set out to identify subgroup-specific mutational patterns and gene regulation. Whole genome sequencing was performed on 62 samples across all MCs and WHO grades from 62 patients with matched blood control, including 40 sporadic meningiomas and 22 meningiomas arising after radiation (Mrad). RNA sequencing was added for 18 of these cases and chromatin-immunoprecipitation for histone H3 lysine 27 acetylation (H3K27ac) followed by sequencing (ChIP-seq) for 16 samples. Besides the known mutations in meningioma, structural variants were found as the mechanism of NF2 inactivation in a small subset (5%) of sporadic meningiomas, similar to previous reports for Mrad. Aberrations of DMD were found to be enriched in MCs with NF2 mutations, and DMD was among the most differentially upregulated genes in NF2 mutant compared to NF2 wild-type cases. The mutational signature AC3, which has been associated with defects in homologous recombination repair (HRR), was detected in both sporadic meningioma and Mrad, but widely distributed across the genome in sporadic cases and enriched near genomic breakpoints in Mrad. Compared to the other MCs, the number of single nucleotide variants matching the AC3 pattern was significantly higher in the malignant MC, which also exhibited higher genomic instability, determined by the numbers of both large segments affected by copy number alterations and breakpoints between large segments. ChIP-seq analysis for H3K27ac revealed a specific activation of genes regulated by the transcription factor FOXM1 in the malignant MC. This analysis also revealed a super enhancer near the HOXD gene cluster in this MC, which, together with general upregulation of HOX genes in the malignant MC, indicates a role of HOX genes in meningioma aggressiveness. This data elucidates the biological mechanisms rendering different epigenetic subgroups of meningiomas, and suggests leveraging HRR as a novel therapeutic target.

Differentiation Researches on the Meningioma Subtypes by Radiomics from Contrast-Enhanced Magnetic Resonance Imaging: A Preliminary Study.

BACKGROUND: Meningioma subtypes are one of the most common key points to the treatment and prognosis of patients. The purpose of this study was to investigate the differential diagnostic value of radiomics features on meningioma. METHODS: A total of 241 patients with meningioma who had undergone tumor resection were randomly selected including 80 with meningothelial meningioma, 80 with fibrous meningioma, and 81 with transitional meningioma. These meningiomas were divided into 4 groups including: meningothelial versus fibrous (group 1), fibrous versus transitional (group 2), meningothelial versus transitional (group 3), and meningothelial versus fibrous versus transitional (group 4). All patients were examined using the same magnetic resonance scanner (GE 3.0 T) and the preoperative contrast-enhanced T1-weighted images were available. Radiomics features from the contrast-enhanced T1-weighted images of 241 patients were evaluated by 2 experienced radiology specialists. RESULTS: A total of 385 radiomics features were extracted from the images of each patient. Several preprocessing methods were applied on the radiomics dataset to reduce the redundancy and highlight differences between different meningioma before the Fisher discrimination analysis was adopted and leave one out cross validation methods were used for the model validation. The differentiation accuracies of the Fisher discriminant analysis model for groups 1, 2, 3, and 4 were 99.4%, 98.8%, 100% and 100%, respectively; leave one out cross validation method was achieved for group 1, 2, 3, and 4 with the accuracies of 91.3%, 95.0%, 100%, and 94.2%, respectively. CONCLUSIONS: Radiomics features and the combined Fisher discriminant analysis could provide satisfactory performance in the preoperative differential diagnosis of meningioma subtypes and enable the potential ability for clinical application.

Characteristic features and proposed classification in 69 cases of intracranial microcystic meningiomas.

Microcystic meningioma (MM) is a rare subtype of intracranial meningiomas, with clinical and radiologic features not well characterized in the literature. Based on our experience, we propose a classification system of intracranial MMs. We reviewed the medical records, radiographic studies, and operative notes of a group of consecutive patients with intracranial MM. The mean age of the 69 patients was 46.8 ± 10.6 years (range, 21-75 years). Three types of intracranial MMs could be identified. Type 1 MMs presented as a solid lesion, hypointense or isointense on T1WI, hyperintense on T2WI, and homogeneous or heterogeneous enhancement, and were found in 43 patients (67.2%). Type 2 MMs represented signals similar to CSF both on T1WI and T2WI, and faint reticular enhancement with marginal enhancement, and these were found in 7 patients (10.9%). Type 3 MMs consisted of cystic-solid or cystic lesion and were found in 14 patients (21.9%). Significant differences were observed among the different types of MMs for the following variables: sex, presence of severe peritumoral brain edema (PTBE), and extent of tumor resection. Females were found in all of patients with type 2 MMs, but were only 35.7% of those with type 3 MMs (P = 0.018). Severe PTBEs were more common among patients with type 1 MMs (55.8%) than among those with type 2 (14.3%) and type 3 MMs (14.3%) (P = 0.007). Type 1 MMs (97.7%) were associated with a significantly higher rate of gross total resection compared with the other two types (71.4 and 78.6%) (P = 0.019). Total length of hospital stay after craniotomy ranged from 4 to 30 days (median, 8 days). There were no significant differences in progression-free survival among the three types of MMs (P = 0.788). The current classification identifies three distinct types of intracranial MM based on their radiological findings and growth patterns. The type 1 MMs are more commonly associated with severe PTBE. Type 2 and Type 3 MMs have a higher predilection towards parasaggital location with venous involvement and therefore have a lower rate of gross total resection.

Improving results in patients with foramen magnum meningiomas by translating surgical experience into a classification system and complexity score.

Foramen magnum meningiomas (FMMs) are challenging lesions and controversy still exists regarding their optimal management. In the present paper, we propose some principles of surgical treatment of FMMs. We analyzed our series of 39 patients: the average maximum diameter was 31.1 mm (sd, 10.7). In two cases, there was extradural extension. We operated all anterior lesions through dorsolateral approach to craniovertebral junction and all posterior lesions through midline suboccipital approach and C1 laminectomy, following the prevalence of side of the tumor. There were no complications except for one case of post-operative hypoglossus paresis. We translated our experience with surgery of foramen magnum meningiomas into a classification system and a complexity score, in order to assign a score to each individual case and plan the surgical strategy. When the complexity score is 5 or more, we propose subtotal removal, in consideration of the benign nature.

Management of meningioma.

Meningiomas are the most frequent primary brain tumors, accounting for ∼37% of central nervous systems tumors. Despite being largely benign, clinicians frequently face difficult treatment decisions in cases with complex morphology or localisation, near vital brain structures such as the optic nerve or in the case of incidental tumors. Here, we review current concepts of diagnosis, treatment and follow-up with clinical decision-making informed by multimodal imaging, histology, and molecular biology.

Treatment Strategy for Tuberculum Sellae Meningiomas Based on a Preoperative Radiological Assessment.

BACKGROUND: Although there are several surgical approaches for the treatment of tuberculum sellae (TS) meningiomas, clear indications for non-large TS meningiomas are still lacking. METHODS: Our case series included 20 patients with TS meningiomas (<3 cm). We classified the tumors into 3 groups based on their radiologic relationship with the optic chiasm: type I, tumor with intact optic chiasm; type II, tumor with superiorly deviated optic chiasm; and type III, tumor with posteriorly deviated optic chiasm. Clinical outcomes, radiologic findings, and surgical approaches for the removal of each tumor type were retrospectively reviewed. RESULTS: Resections using a pterional approach, interhemispheric approach, and an endoscopic endonasal approach were performed in three groups of 6, 7, and 7 patients. The rate of total tumor resection was equivalent across approaches, whereas postoperative visual dysfunction was observed in 1 patient (7.69%) undergoing a transcranial approach. Our evaluation of the sphenoid sinus shape across radiographs revealed that the patterns of bony wall elongation attached to these tumors significantly differed among tumor types, indicating that tumor origin and growth direction might affect the patterns of optic chiasm deviation. In addition, selective elongation of the TS provided a favorable surgical corridor for an endoscopic endonasal approach, especially in type II tumors. These results indicate that this tumor classification influenced surgical approach selection for non-large TS meningiomas. CONCLUSIONS: The aim of surgery is maximal tumor resection without causing visual dysfunction. The classification proposed here may predict surgical risk associated with meningioma resection and further inform the selection of a surgical approach.