[The Transcranial Approach for Parasellar Meningiomas].

Patients with parasellar meningiomas often initially present with visual impairment. Understanding the surrounding anatomy is essential when preparing for surgery of parasellar meningiomas, as this region includes various crucial neurovascular structures. Historically, invasive craniotomy, such as the orthozygomatic approach or zygotomy, has often been attempted to access the region; however, the use of these invasive approaches has become less common, because of the accumulation of anatomical knowledge, as well as the development of surgical techniques and devices, including the endonasal endoscopic approach. Herein, we summarize how we perform surgery for parasellar meningiomas, and outline tips and pitfalls that could be useful for young residents and trainees who are new to the skull base field.

[Surgical Approaches for Cerebellopontine Angle/Petroclival Meningiomas].

Considering that most meningiomas are pathologically benign, tumors located in the cerebellopontine angle and petroclival area should be reduced as much as possible, and radiation therapy should be administered if necessary. Consequently, relatively good preservation of cranial nerve function and local lesion control can be expected. However, because the lesions are generally located deep, and are surrounded by various important structures, performing surgical procedures is difficult, and careful management of the surgical strategy is important to avoid complications. Surgical outcomes have dramatically improved with the development of skull base and microsurgical techniques. The main surgical approaches for cerebellopontine angle meningiomas and petroclival meningiomas currently include the anterior and posterior combined transpetrosal, anterior transpetrosal, and lateral suboccipital approaches. Furthermore, with the recent developments in endoscopic surgery, minimally invasive surgery for skull base meningiomas has gradually been introduced. In this article, we explain the preoperative checkpoints, selection of the surgical approach, and surgical techniques for the resection of cerebellopontine angle meningiomas and petroclival meningiomas.

[Epidemiology, Natural History, and Growth Risk of Meningiomas].

Meningiomas are the most common primary intracranial tumors. As the number of incidentally discovered meningiomas has increased with the widespread access and use of neuroimaging, treatment strategies for meningiomas have become more important. Close observation is the first choice for asymptomatic lesions; however, the natural history of meningiomas remains unclear. It is necessary to recognize the characteristics of meningiomas that are likely to grow, such as high signal intensity on MRI T2WI. It is also important to examine the growth rates and patterns using multiple neuroimaging examinations during the follow-up period. The authors suggested a relationship between the various observed growth patterns and the length of the follow-up period based on the assumed development of tumor volume. Less than 10% of patients with asymptomatic meningiomas develop symptoms and require treatment. However, it remains unclear which lesions become symptomatic, and further studies are required. Lesions with a sustained growth pattern undergo preventive treatment interventions, but the need for and appropriate timing of these interventions are continuously under debate. Further studies will help elucidate the natural history of meningiomas.

[Malignant Transformation of Benign Meningiomas with or without Radiotherapy].

Most meningiomas are benign, slow growing tumors, which rarely progress to a higher grade. The incidence rate of malignant progression is estimated to be 2.98/1000 patient-year. However, non-skull base location is a significant risk factor for progression. The median time to malignant progression is 4.3 years; however, the cumulative rate of progression approaches a plateau after 10 years. Although radiosurgery does not appear to increase the incidence rate(0.5/1000 patient-year), exact comparisons have been difficult because of differences in study populations. The median time to progression is 7.0 years from initial diagnosis and 5.0 years from radiosurgery. The cumulative rate appears to increase even after 10 years. The risk of malignant transformation after radiotherapy may increase in patients with tumor-prone syndromes, with some controversies regarding patients with neurofibromatosis type 2. Although short term follow-up in patients with meningioma suggests that radiosurgery is safe, there is uncertainty regarding its use in pediatric patients, and those with tumor-prone syndromes.

[Necessity of Meningioma Capsulectomy].

The need for resection of the meningioma capsule has long been debated and remains controversial. Even the definition of a capsule does not seem to have been established. We described the histopathological findings of the so-called capsule and the necessity for resection, considering tumor cell invasion and recurrence, based on a literature review.

Surgical outcomes of trigonal intraventricular meningiomas: a single-centre study.

Trigonal meningiomas are rare intraventricular tumours that present a surgical challenge. There is no consensus on the optimal surgical approach to these lesions, though the transtemporal and transparietal approaches are most frequently employed. We aimed to examine the approach-related morbidity and surgical nuances in treating trigonal meningiomas. This retrospective review assimilated data from 64 trigonal meningiomas operated over 15 years. Details of clinicoradiological presentation, surgical approach and intraoperative impression, pathology and incidence of various postoperative deficits were recorded. In our study, Trigonal meningiomas most frequently presented with headache and visual deterioration. The median volume of tumours was 63.6cc. Thirty-one meningiomas each (48.4%) were WHO Grade 1 and WHO Grade 2, while 2 were WHO Grade 3. The most frequent approach employed was transtemporal (38 patients, 59.4%), followed by transparietal (22 patients, 34.4%). After surgery features of raised ICP and altered mental status resolved in all patients, while contralateral limb weakness resolved in 80%, aphasia in 60%, seizures in 70%, and vision loss in 46.2%. Eighteen patients (28.13%) developed transient postoperative neurological deficits, with one patient (1.5%) developing permanent morbidity. Surgery for IVMs results in rapid improvement of neurological status, though visual outcomes are poorer in patients with low vision prior to surgery, longer duration of complaints and optic atrophy. The new postoperative deficits in some patients tend to improve on follow up. Transtemporal and transparietal approaches may be employed, based on multiple factors like tumour extension, loculation of temporal horn, size of lesion with no significant difference in their safety profile.

Stereotactic radiosurgery for intraventricular meningioma: a systematic review and meta-analysis.

BACKGROUND: Intraventricular meningioma (IVM) is a rare subtype of intracranial meningioma, accounting for 9.8 to 14% of all intraventricular tumors. Currently, there is no clear consensus on which patients with IVM should receive conservative treatment, surgery, or stereotactic radiosurgery (SRS). This research aims to analyze the outcomes, including survival and recurrence rates of patients who undergo SRS for IVM as a primary or adjuvant treatment. METHODS: A systematic search was conducted in Scopus, Web of Science, PubMed, and Embase till June 5th 2023. Screening and data extraction were performed by two independent authors. Random-effect meta-analysis was performed to determine the tumor control proportion of IVM cases treated with SRS. Individual patient data (IPD) meta-analysis was performed for the progression-free survival (PFS) of the patients in the follow-up time. All analyses were performed using the R programming language. RESULTS: Out of the overall 132 records, 14 were included in our study, of which only 7 had enough data for the meta-analysis. The tumor control proportion was 0.92 (95% CI, 0.69-0.98) in patients who underwent SRS for primary IVM. The overall tumor control in both primary and adjuvant cases was 0.87 (95% CI, 0.34-0.99). the heterogeneity was not significant in both meta-analyses (P = 0.73 and P = 0.92, respectively). Post-SRS perifocal edema occurred in 16 out of 71 cases (0.16; 95% CI, 0.03-0.56), with no significant heterogeneity (P = 0.32). IPD meta-analysis showed a PFS of 94.70% in a 2-year follow-up. Log-rank test showed better PFS in primary SRS compared to adjuvant SRS (P < 0.01). CONCLUSIONS: According to this study, patients with IVM can achieve high rates of tumor control with a low risk of complications when treated with SRS, regardless of whether they have received prior treatment. Although SRS could be a promising first-line treatment option for asymptomatic IVM, its efficacy in symptomatic patients and its comparison with resection require further investigation.

Atypical and anaplastic meningiomas in the later decades of life: A national cancer database analysis.

PURPOSE: We conducted a National Cancer Database (NCDB) study to investigate the epidemiological characteristics and identify predictors of outcomes associated with geriatric meningiomas. METHODS: The NCDB was queried for adults aged 60-89 years diagnosed between 2010 and 2017 with grade 2 and 3 meningiomas. The patients were classified into three age groups based on their age: 60-69 (hexagenarians), 70-79 (septuagenarians), and 80-89 (octogenarians). The log-rank test was utilized to compare the differences in overall survival (OS). Univariate and multivariate Cox proportional hazards regressions were used to evaluate the mortality risk associated with various patient and disease parameters. RESULTS: A total of 6585 patients were identified. Hexagenerians were the most common age group (49.8%), with the majority of meningiomas being classified as grade 2 (89.5%). The incidence of high-grade meningiomas increased in all age groups during the study period. Advanced age, male sex, black race, lower socioeconomic status, Charlson-Deyo score ≥ 2, and higher tumor grade were independent factors of poor survival. Among the modes of treatment, the extent of surgical resection, adjuvant radiotherapy, and treatment at a noncommunity cancer program were linked with better outcomes. CONCLUSION: In geriatric patients with high-grade meningiomas, the greater extent of surgical resection and radiotherapy are associated with improved survival. However, the management and outcome of geriatric patients with higher-grade meningiomas are also associated with several socioeconomic factors.

NF2 regulates IP3R-mediated Ca2+ signal and apoptosis in meningiomas.

Meningiomas are the most common primary intracranial tumors and account for nearly 30% of all nervous system tumors. Approximately half of meningioma patients exhibit neurofibromin 2 (NF2) gene inactivation. Here, NF2 was shown to interact with the endoplasmic reticulum (ER) calcium (Ca2+) channel inositol 1,4,5-trisphosphate receptor 1 (IP3R1) in IOMM-Lee, a high-grade malignant meningioma cell line, and the F1 subdomain of NF2 plays a critical role in this interaction. Functional assays indicated that NF2 promotes the phosphorylation of IP3R (Ser 1756) and IP3R-mediated endoplasmic reticulum (ER) Ca2+ release by binding to IP3R1, which results in Ca2+-dependent apoptosis. Knockout of NF2 decreased Ca2+ release and promoted resistance to apoptosis, which was rescued by wild-type NF2 overexpression but not by F1 subdomain deletion truncation overexpression. The effects of NF2 defects on the development of tumors were further studied in mouse models. The decreased expression level of NF2 caused by NF2 gene knockout or mutation affects the activity of the IP3R channel, which reduces Ca2+-dependent apoptosis, thereby promoting the development of tumors. We elucidated the interaction patterns of NF2 and IP3R1, revealed the molecular mechanism through which NF2 regulates IP3R1-mediated Ca2+ release, and elucidated the new pathogenic mechanism of meningioma-related NF2 variants. Our study broadens the current understanding of the biological function of NF2 and provides ideas for drug screening of NF2-associated meningioma.

Clinicopathological characteristics of secondary trigeminal neuralgia due to cerebellopontine angle tumors. / æ¡¥å°è„‘è§’è‚¿ç˜¤ç»§å‘æ€§ä¸‰å‰ç¥žç»ç—›çš„ä¸´åºŠç— ç†ç‰¹å¾.

OBJECTIVES: Cerebellopontine angle (CPA) tumors are a common cause of secondary trigeminal neuralgia (TN), characterized by their concealed location, slow progression, and difficulty in early detection. This study aims to explore the clinicopathological characteristics of patients with secondary TN due to CPA tumors to enhance understanding and management of secondary TN. METHODS: A retrospective analysis was conducted on clinical data and pathological results of 116 patients with CPA tumor-related TN treated at Xiangya Hospital of Central South University from January 1, 2017 to December 31, 2022. The study analyzed the relationship of tumor pathological types with clinical manifestations, tumor location, surgical methods, and treatment outcomes. RESULTS: Among the cases, 95.7% (111/116) were benign tumors, 3.4% (4/116) were malignant tumors, and 0.9% (1/116) were borderline tumors. Benign tumors were predominantly acoustic neuromas, meningiomas, and schwannomas. Among the patients, 46.6% (54/116) presented with isolated TN, while 53.4% (62/116) exhibited other associated symptoms depending on factors such as tumor growth location and rate. The complete resection rate in this group was over 90%, with 41.4% (48/116) of patients undergoing concurrent microvascular decompression after tumor resection, predominantly for schwannomas. The overall effective rate of surgical treatment reached 93.9%, with schwannomas showing higher efficacy rates compared with acoustic neuromas and meningiomas (P<0.05). The recurrence rate of acoustic neuromas was significantly higher than that of meningiomas and schwannomas (P<0.05). CONCLUSIONS: CPA tumors are a major cause of secondary TN, predominantly benign, with occasional underdiagnosed malignant tumors. Early diagnosis and treatment significantly impact prognosis. Different tumor types vary in clinical symptoms, surgical approaches, and treatment efficacy. Surgical strategies should balance tumor resection extent and neural function preservation, with microvascular decompression as necessary.

Impact of BrainLab VectorVision Infrared-Based Neuronavigation on Surgical Outcomes in Intracranial Meningioma Patients: A Retrospective Study.

BACKGROUND The BrainLab VectorVision neuronavigation system is an image-guided, frameless localization system used intraoperatively, which includes a computer workstation for viewing and analyzing operative microscopic images. This retrospective study aimed to evaluate the use of the BrainLab VectorVision infrared-based neuronavigation imaging system in 80 patients with intracranial meningioma removed surgically between 2013 and 2023. MATERIAL AND METHODS Data were retrospectively collected from 36 patients with convexity meningioma and 44 patients with parasagittal meningioma between 2013 and 2023. The surgical operation of 40 of these patients was performed with the help of neuronavigation, while the other 40 were performed without neuronavigation. Demographic data, preoperative and postoperative radiologic images, craniotomy measurements, surgical complications, and operative times of patients with and without neuronavigation were analyzed. RESULTS Using neuronavigation significantly increased surgery duration (P=0.023). In 6 patients without the use of neuronavigation, the craniotomy had to be enlarged and this resulted in superior sagittal sinus (SSS) damage (P=0.77, P=0.107). Patients for whom neuronavigation was used did not experience any sinus damage and did not require craniotomy enlargement. Postoperative epidural hematoma (EH) developed in 9 patients without navigation, whereas it developed in only 1 patient with navigation (P=0.104). Residual tumors were less common in patients using navigation (P=0.237). CONCLUSIONS The use of neuronavigation allows the incision and craniotomy to be reduced in size. Intraoperatively, it allows the surgeon to master the boundaries of the tumor and surrounding vascular structures, reducing the risk of complications. These results suggest that neuronavigation systems are an effective ancillary in meningioma surgery.

Analysis of the treatment planning metrics and their correlation with morphology of intracranial lesions in Gamma Knife stereotactic radiosurgery.

BACKGROUND: Gamma Knife Radiosurgery (GKRS) has established a role in treating various benign brain pathologies. The radiosurgery planning necessitates a proper understanding of radiation dose distribution in relation to the target lesion and surrounding eloquent area. The quality of a radiosurgery plan is determined by various planning parameters. Here, we have reviewed various GKRS planning parameters and analyzed their correlation with the morphology of treated brain lesions. METHOD: A total of 430 treatment plans (71 meningioma, 133 vestibular schwannoma/VS, 150 arteriovenous malformation/AVM, 76 pituitary adenoma/PA treated with GKRS between December 2013 and May 2023) were analyzed for target coverage (TC), conformity index (CI), homogeneity index (HI), and gradient index (GI). RESULT: The values of CIPaddick and CILomax for PA were lower and differed significantly from meningioma, VS, and AVM. The value of HI for PA was higher and differed significantly when compared with meningioma, VS, and AVM. The values of HI for AVM were also significantly higher than VS and meningioma. The mean GI was 3.02, 2.92, 3.03, and 2.88 for meningioma, VS, AVM, and PA, respectively. The value of GI for meningioma and AVM was significantly higher when compared with the values for VS and PA. The mean TC was 0.94 for meningioma, 0.96 for VS, 0.95 for AVM, and 0.90 for PA. The value TC of PA was lower and differed significantly when compared with VS, AVM, and meningioma. Lesions with a volume of ≤1 cc had poor planning metrics as the spillage of radiation may be higher. CONCLUSION: The GKRS planning parameters depend on the size, shape, nature, and location of intracranial lesions. Therefore, each treatment plan needs to be evaluated thoroughly and a long-term follow-up is needed to establish their relation with clinical outcome.

Full Endoscopic Transcranial Resection of Meningiomas.

OBJECTIVE: Tumors of the skull base can be accessed through different routes. Recent advantages in minimally invasive techniques have shown that very different routes can be applied for optimal tumor resection depending on the technical equipment, the surgeon's preference, and the individual anatomy of the pathology. Here, the authors present their technique for pure endoscopic transcranial tumor resection in meningiomas. METHODS: Out of the cases of the Department of Neurosurgery, Homburg Saar Germany of the last 10 years, all endoscopic procedures for meningiomas were analyzed. Particular attention was given to evaluating the peculiarities of those meningiomas that were treated purely endoscopically. RESULTS: While the endoscope was used in a large number of skull base meningiomas in endonasal approaches or for endoscopic inspection in transcranial skull base surgery, only a small number of meningiomas was selected for a purely endoscopically performed resection. The characteristics of these cases were rather a small lesion, straight access, and a keyhole position of the craniotomy. A complete resection of the tumor was achieved in all cases. Conversion to the microscope was not necessary in any case. There were no technical issues or complications associated with a fully endoscopic resection. DISCUSSION: The endoscope is a valuable tool for visualization in meningioma surgery. In most cases, it is applied for an endonasal route or for endoscopic inspection in transcranial microsurgical cases. However, small to medium-sized meningiomas that can be accessed through the keyhole approach are good candidates for pure endoscopic resection. Because of the very high magnification and the minimally invasive nature of this approach, it should be considered more frequently in suitable lesions.

Fully Endoscopic Supraorbital Approach for Anterior Cranial Base Meningiomas.

BACKGROUND: Anterior cranial base meningiomas include those meningiomas originating from the tuberculum sellae, the planum sphenoidale, or the olfactory groove, with surgical excision being the main treatment modality for these tumors. Conventional microscopic and endoscope-assisted versions of the supraorbital keyhole approach via an eyebrow incision emerged into minimally invasive options that are frequently utilized nowadays for treating these tumors. At the early attempts of endoscope-assisted cranial surgery, it was noted that rigid endoscopes enabled overcoming the problem of suboptimal visualization when small exposures are used. The technical specifications and design of the currently available rigid endoscopes are associated with a group of unique features that define the endoscopic view and lay the basis for its superiority over the microscopic view during brain surgery. Notwithstanding, the fully endoscopic or endoscope-controlled version of the supraorbital keyhole approach is not routinely practiced by neurosurgeons, with few series published so far. In this chapter we elaborate on the surgical technique and nuances of the fully endoscopic supraorbital approach for anterior cranial base meningiomas. METHODS: From a prospective database of endoscopic procedures maintained by the senior author, clinical data, imaging studies, operative charts, and videos of cases undergoing fully endoscopic excision of anterior cranial base meningiomas via supraorbital approach were retrieved and analyzed. The pertinent literature was also reviewed. RESULTS: The surgical technique of the fully endoscopic supraorbital approach for anterior cranial base meningiomas was formulated. CONCLUSION: The fully endoscopic supraorbital approach for anterior cranial base meningiomas has many advantages over the conventional procedures. In our hands, the technique has proven to be feasible, efficient, and minimally invasive with excellent results.

Expression of somatostatin receptors in canine and feline meningioma.

OBJECTIVES: The standard treatment for canine and feline meningiomas includes radiotherapy, surgical excision or combined therapy. However, new therapeutic approaches are required due to the possible recurrence or progression of meningiomas despite initial therapy. Adjunctive therapy with synthetic long-acting somatostatin (SST) analogues has been described in humans with SST-expressing tumours. The expression of SST receptors (SSTRs) by feline meningiomas is currently unknown, and there are little data about canine meningiomas. We hypothesized that SSTR is expressed by canine and feline meningiomas (S1). METHODS: Seven canines and 11 felines with histologically confirmed meningiomas underwent STTR screening. RNA expressions of SSTR1, SSTR2, SSTR3 and SSTR5 (canine) and SSTR1-SSTR 5 (feline) in fresh frozen and formalin-fixed and paraffin-embedded (FFPE) samples were investigated using real-time (RT)-qPCR. The expression of SSTR1 and SSTR2 in FFPE samples was evaluated using immunohistochemistry (IHC). The specificity of applied antibodies for canine and feline species was confirmed by western blotting. RESULTS: In canine meningiomas (n = 7), RNA expression of SSTR1, SSTR2 and SSTR5 was detected in all samples; SSTR3 RNA expression was detected in only 33% of samples. In feline meningiomas (n = 12), RNA expression of SSTR1, SSTR4, SSTR5 and SSTR2 was detected in 91%, 46%, 46% and 36% of samples, respectively; SSTR3 was not expressed. Overall, the detection rate was lower in FFPE samples. IHC revealed the expression of SSTR1 and SSTR2 in all samples from both species. However, it is important to exercise caution when interpreting IHC results due to the presence of diffuse background staining. CONCLUSIONS: SSTRs are widely expressed in canine and feline meningiomas, thereby encouraging further studies investigating SSTR expression to conduct trials about the effect of adjunctive therapy with long-acting SST-analogues.

Study of the stress in adults diagnosed with meningioma: Insights from a tertiary neurosurgical hospital.

BACKGROUND: Meningiomas are the most common type of primary brain tumor, originating from the meninges - the protective membranes that surround the brain and spinal cord. Several well-studied risk factors for meningiomas include gender, age, radiation exposure, genetic factors, and hormonal factors. Moreover, the influence of a person's psycho-emotional stateon their overall health and mental well-being, specifically stress, iscurrently a significant and relevant topic of discussion. AIMS: This case-control study aimed to study the association between perceived stress, chronic stress, and meningioma in adult patients. METHODS AND RESULTS: The study included cases, which comprised adult patients with histologically confirmed meningioma, and controls, consisting of adult patients with no history of brain cancer. Data collection involved the use of three types of questionnaires. The first questionnaire focused on patients' personal information, geographic factors, and lifestyle habits. Two additional questionnaires "The Perceived Stress Scale" and "The Chronic Stress Scale" were employed to assess perceived stress and chronic stress. The questioning was conducted by a neurologist. Microsoft Excel and Stata 14 were used for the data analysis. Overall, 148 questionnaires were completed and included in the analyses. The average age of participants was 45.60 ± 13.90 years. Females outnumbered males in both groups. Patients with meningioma diagnosis had a higher level of perceived high stress compared to those without meningioma (p = .045). Respondents without a diagnosis of meningioma have reported having more chronic stress in general and ambient problems (p = .004), financial issues (p = .006), work (p < .001), non-employment (p = .008), love and marriage (p < .001), isolation (p < .001), and residence (p < .001). Patients with meningioma, however, had less chronic stress compared to meningioma-free patients. CONCLUSION: This study revealed no discernible connection between stress and meningioma within our study sample. Further research with matched case-control methodology with a larger sample size is warranted to thoroughly evaluate the potential role of stress in patients with meningioma.

[Prediction of the Natural Course of Meningioma Using CT and MR Images].

The frequency of identification of asymptomatic meningiomas is increasing owing to the advancement and widespread use of CT and MRI. The first choice for asymptomatic meningiomas is observation. Approximately 70% of asymptomatic meningiomas increase in volume on long term follow-up. More than half of them reportedly exhibit a self-limiting pattern, in which growth eventually stops. Imaging findings related to increased meningioma volume include no calcification, large tumor size, high signal intensity inside the tumor on T2-weighted images, high brightness within the tumor on diffusion-weighted images, and perifocal edema. We also highlighted the presence of hypo-intensity of the surface layer on T2-weighted imaging, indicating growth arrest in a self-limiting growth pattern of meningioma. In this article, literature reports on image prediction using CT and MRI regarding the growth of asymptomatic meningiomas were reviewed, along with our report.

[Convexity Meningioma, Parasagittal Meningioma, Falx Meningioma].

During surgery for meningioma, basic surgical techniques and strategies required for the removal of the tumor are common, particularly for tumors located superficially, such as convexity, parasagittal, and falx meningiomas. Four basic surgical techniques, including detachment; devascularization; debulking; and dissection should be combined and repeated in appropriate sequence, tailored to the specific conditions of each tumor. This eventually enables the total circumferential dissection of the tumor from the surrounding tissues. It is essential to retract the tumor towards the space created at the tumor center through internal debulking, rather than retracting the normal brain, to avoid damage to the surrounding brain tissue. During surgery for parasagittal meningioma with venous sinus occlusion, it is crucial to preserve the cortical veins that have developed as collateral pathways to prevent venous complications. During surgery for falx meningioma, the selection of a surgical approach including a contralateral approach based on factors such as the development of bridging veins and significant peritumoral brain edema is required. In this article, detailed surgical procedures for convexity meningioma, parasagittal meningioma, and falx meningioma were described focusing on the application of fundamental surgical techniques tailored to each tumor type.

[Pathological Diagnosis and Genetic Alterations of Meningioma].

Meningiomas, renowned for their histological diversity, are one of the most prevalent brain tumors. Some meningiomas show unusual histomorphology, especially in intraoperative rapid diagnosis. Therefore, clinical and radiological information is crucial for pathological diagnosis. Before the 2021 World Health Organization Classification of Tumors of the Central Nervous System(5th edition), pathological diagnosis relied solely on histopathological features. However, this classification introduced new diagnostic criteria for anaplastic meningiomas, which now include TERT promoter mutations and the homozygous deletion of CDKN2A/B, indicating the necessity of genetic analysis. Some rhabdoid and papillary meningiomas have BAP1 alterations, which tend to demonstrate an aggressive clinical course and may represent a phenotype of BAP1-related tumor predisposition syndrome. Heterozygous deletion of CDKN2A/B and loss of H3 p.K28me3(K27me3)are also associated with poor prognosis. Although some immunohistochemical markers like MTAP may serve as surrogates for the homozygous deletion of CKKN2A/B, genetic analysis is required to confirm TERT promoter mutations. Therefore, in routine clinical practice, neurosurgeons and pathologists prioritize appropriate formalin fixation to facilitate genetic analysis using pathological specimens.