Simpson Grade Research Articles

Risk factors analysis of clinical features with surgical resection rate and prognosis of petroclival meningioma with main body in posterior fossa

ObjectiveOur retrospective study aimed to investigate the relation of clinical features with surgical resection degree and prognosis of petroclival meningioma (PCM) whose main body in the posterior fossa and summarized the experience of surgery. We worked on improving the cure rate of PCM patients from both clinical data analysis and surgical experience. MethodsWe retrospectively analyzed 62 patients of the main body of PCM locating in the posterior fossa. Clinical data included basic information of patients, video of surgery, and post-operation follow-up. Clinical results were evaluated by Karnofsky Performance Score (KPS). The degree of surgical resection was evaluated by Simpson grade. Tumor resection degree and postoperative complications were performed by univariate and multivariate analyses. ResultsThe analyses showed gross total resection achieved in 50 cases (81.97%), and subtotal resection in 11 cases (18.03%). There were 38 cases (62%) without complications after operation. The preoperative KPS score of 19 cases were ≥ 80, and the postoperative KPS score of 51 cases were ≥80. The results showed that resection degree and quality of life were connected to Edema and adhesion of the brainstem, and postoperative complications were associated with age, tumor size and wrap of vessel. ConclusionsEdema and adhesion of the brainstem caused by tumor compression is an independent risk factor of surgical resection degree and quality of life in patients with PCM; Age, tumor size and wrap of vessel are independent risk factors of postoperative complications in patients with PCM.

Pterional versus anterior interhemispheric approach in anterior skull base meningiomas: A comparative study

IntroductionThe pterional approach and anterior interhemispheric approach are both valid surgical routes for the treatment of anterior skull base meningiomas. Comparative studies of these two surgical routes are not yet reported in the literature. Research questionThis retrospective study aims to compare the surgical outcome of both approaches, pros, and cons as well as potential postoperative complications. Materials and methodsIn this retrospective study the following variables were evaluated: age, sex, meningioma location, symptoms, post-surgical complications, Simpson grade, follow-up/Outcome (maximum six months), hospital stay (days), Intraoperative time (minutes), intra-operative blood loss (mL). ResultsThis retrospective study included a total of 22 patients (18 females and 4 males) with a female/male ratio of 4,5/1. The mean age was 59,5 ± 12,59 years. In 13 patients (59%) an anterior interhemispheric approach was performed; in 9 (41%) patients an extended pterional approach. Comparing the two surgical techniques operative time it was found a significant difference between the two approaches (p = 0,03), and a significant difference (p = 0,016) was found in blood losses during surgical procedures: a lower operative time with a higher blood loss was found performing the anterior interhemispheric approach. Discussion and conclusionThe pterional approach and anterior interhemispheric approach are two possible surgical options for the treatment of anterior skull base meningiomas. Both approaches have achieved optimal results, with total tumor resection in most patients and a low complication rate, and that the best approach depends mainly on the experience of the surgeons. A larger cohort of patients with a longer follow-up is needed to propose an algorithm to select the most suitable surgical route for surgical resection, thus reducing the risks.

Malignant transformation of meningioma: Case report.

Meningiomas are mostly benign brain tumors with minimal malignant cases. Anaplastic meningioma has malignant morphological characteristics and a World Health Organization grade of III. The present study reports a case of an occipital meningioma in a patient who initially chose observation and follow-up after diagnosis. The patient ultimately underwent surgery due to the enlargement of the tumor and the development of visual field defects after a decade of imaging follow-up. The postoperative pathology slides indicated the presence of an anaplastic meningioma (World Health Organization-grade III). The patient's diagnosis was established through cranial magnetic resonance imaging, which revealed an irregular mixed mass in the right occipital region with isointense T1 and hypointense T2 signal, irregular lobulation, and a maximum diameter of approximately 5.4 cm. Heterogenous enhancement was observed in the contrast-enhanced scan. The patient opted for surgical intervention to remove the tumor, and the pathology slides of the tumor sample confirmed the diagnosis of anaplastic meningioma. The patient also received radiotherapy (40Gy/15fr). No recurrence was observed during the 9-month follow-up. This case highlights the potential for low-grade meningiomas to undergo malignant transformation, particularly in the presence of irregular lobulation, peritumoral brain edema, and heterogeneous enhancement on contrast-enhanced scans. Total excision (Simpson grade I) is the preferred treatment option, and long-term imaging follow-up is recommended.

Endoscopic Supraorbital Eyebrow Approach for Medium-Sized Tuberculum Sellae Meningiomas: A Cadaveric Stepwise Dissection, Technical Nuances, and Surgical Outcomes

Tuberculum sellae meningiomas (TSMs) have traditionally been removed using a transcranial approach. In recent years, endoscopic surgery for TSMs has been reported with an expansion of indications. We have performed a fully endoscopic supraorbital keyhole approach for small to medium-sized TSMs and performed radical tumor removal similar to conventional transcranial procedure. We report the details of this surgical procedure including cadaveric stepwise dissection and initial surgical results for small to medium-sized TSMs. We used an endoscopic supraorbital eyebrow approach for 6 patients with TSMs between September 2020 and September 2022. Mean tumor diameter was 16.0 mm (range, 10-20 mm). The surgical approach included an eyebrow skin incision ipsilateral to the lesion, a small frontal craniotomy, subfrontal exposure of the lesion, removal of the tuberculum sellae, unroofing of the optic canal, and resection of the tumor. The extent of resection, preoperative and postoperative visual function, complications, and operative time were evaluated. Optic canal involvement was observed in all patients. Two patients (33%) showed visual dysfunction before surgery. Simpson grade 1 tumor resection was achieved in all cases. Visual function was improved in 2 cases, and remained unchanged in 4 cases. Postoperative pituitary function was preserved in all cases, with no decreases in olfaction. The endoscopic supraorbital eyebrow approach for TSMs allowed resection of the lesion, including tumor extending to the optic canal, with a good surgical view. This technique is minimally invasive for patients and may represent a good surgical option for medium-sized TSMs.

Diploic Bone Channel Drilling Facilitates Dissection of the Midline Dura and Protects the Superior Sagittal Sinus in Hyperostosis Frontalis Interna.

Patients with space-occupying lesions adjacent to thesuperior sagittal sinus (SSS) present several technical considerations.For craniotomies crossing the SSS, a two-part method allows for dissection of the epidural space and dura under direct vision after removing a more lateral parasagittal bone flap. However, when the inner table surface of the medial component of the two-part bone flap is irregular, this can be difficult. We describe a method for channel drilling of the diploic bone, which allows for the piecemeal removal of the inner table using an upbiting rongeur. This article presents the case of meningioma with documented growth and provides a technical note of this techniquetofacilitate safe dissection of the midline dura. A patient presented with headaches and an anterior one-third parasagittal meningioma with documented growth. She selected surgical removal for treatment. A right frontal two-part parasagittal craniotomy was recommended. The preoperative imaging showed that the frontal bone was thick, with irregularity of the inner table. Intraoperatively, a channel was drilled in the diploic space of the bone, leaving the outer table intact. This provided a thin lip of the inner table that could be dissected over a short distance and then removed with a 2-mm upbiting rongeur. This allowed for further dissection of the dura crossing the midline under direct vision and safe secondary bone piece removal. The dura was opened to the edge of the SSS, allowing full exposure of the parasagittal region and interhemispheric fissure, thus limiting retraction of the medial right frontal lobe.The bone flap was removed in two pieces without a dural tear over the midline in spite of inner table irregularities. A Simpson grade 1 removal was accomplished, including excision of the affected falx, and the postoperative course was uncomplicated. In conclusion, diploic bone channel drilling is a technique that can be used to create a thin lip of the inner table, which can be removed piecemeal for safe dissection of the midline dura crossing the midline.

Correlation Based on the WHO Grading with Tumor Control and Clinical Outcome Following Gamma Knife Radiosurgery in Meningiomas.

The aim of this study was to study the effect of Gamma Knife (GK) on meningiomas based on the World Health Organization's (WHO) grading system in terms of tumor control and final clinical outcome. This retrospective study included clinicoradiological and GK characteristics of patients who had undergone GK for meningiomas at our institute from April 1997 until December 2009. Of 440 patients, 235 underwent secondary GK for residual/recurrent lesion and 205 received primary GK. Of the 137 patients whose biopsy slide could be reviewed, 111 patients had grade I, 16 had grade II, and 10 had grade III meningiomas. Good tumor control rates were seen in 96.3% of grade I meningioma patients, 62.5% of 16 grade II, and 10% of grade III meningioma patients at median follow-up of 40 months. Age, sex, Simpson's grade of excision, and increasing peripheral dose of GK did not affect the response to radiosurgery (P > 0.05). Multivariate analysis showed that high-grade tumor and radiotherapy prior to GK were important negative predictors for progression of tumor size after GK radiosurgery (GKRS) (P < 0.05). In patients with WHO grade I meningioma, radiation therapy prior to GKRS and repeat surgery were predictors for poorer outcome. In WHO grades II and III meningiomas, no factors affected tumor control except the histology itself.

Simpson's Grading Scale for WHO Grade I Meningioma Resection in the Modern Neurosurgical Era: Are We Really Asking the Right Question?

The Simpson grading scale for the classification of the extent of meningioma resection provided a tremendous movement forward in 1957 suggesting increasing the extent of resection improves recurrence rates. However, equal, if not greater, movements forward have been made in the neurosurgical community over the last half a century owing to improvements in neuroimaging capabilities, microsurgical techniques, and radiotherapeutic strategies. Sughrue et al proposed the idea that these advancements have altered what a "recurrence" and "subtotal resection" truly means in modern neurosurgery compared with Simpson's era, and that a mandated use of the Simpson Scale is likely less clinically relevant today. A subsequent period of debate ensued in the literature which sought to re-examine the clinical value of using the Simpson Scale in modern neurosurgery. While a large body of evidence has recently been provided, these data generally continue to support the clinical importance of gross tumor resection as well as the value of adjuvant radiation therapy and the importance of recently updated World Health Organization classifications. However, there remains a negligible interval benefit in performing overly aggressive surgery and heroic maneuvers to remove the last bit of tumor, dura, and/or bone just for the simple act of achieving a lower Simpson score. Ultimately, meningioma surgery may be better contextualized as a continuous set of weighted risk-benefit decisions throughout the entire operation.

Classification and microsurgical treatment of foramen magnum meningioma

BackgroundTo investigate the classification and microsurgical treatment of foramen magnum meningioma (FMM).MethodsWe retrospectively analyzed 76 patients with FMM and classified them into two classifications, classification ABS according to the relationship between the FMM and the brainstem and classification SIM according to the relationship between the FMM and the vertebral artery (VA). All patients underwent either the far lateral approach (54 cases) or the suboccipital midline approach (22 cases).ResultsOf the 76 cases, 47 cases were located ahead of the brainstem (A), 16 cases at the back of the brainstem (B), and 13 cases were located laterally to the brainstem (S). There were 15 cases located superior to the VA (S), 49 cases were inferior (I), and 12 cases were mixed type (M). Among 76 cases, 71 cases were resected with Simpson grade 2 (93.42%), 3 with Simpson grade 3 (3.95%), and 2 with Simpson grade 4 (2.63%). We summarized four anatomical triangles: triangles SOT, VOT, JVV, and TVV. The mean postoperative Karnofsky performance score was improved in all patients (p < 0.05). However, several complications occurred, including hoarseness and CSF leak.ConclusionABS and SIM classifications are objective indices for choosing the surgical approach and predicting the difficulty of FMMs, and it is of great importance to master the content, position relationship with the tumor, and variable anatomical structures in the four “triangles” for the success of the operation.

In Reply: Transcriptomic Profiling Revealed Lnc-GOLGA6A-1 as a Novel Prognostic Biomarker of Meningioma Recurrence.

To the Editor: We read with great interest the letter to the editor by Dr Wang titled “Letter: Transcriptomic Profiling Revealed Lnc-GOLGA6A-1 as a Novel Prognostic Biomarker of Meningioma Recurrence”1 and are deeply appreciative of his interest in our study.2 The extent of surgical resection is among the most important predictors of meningioma recurrence.3,4 In our retrospective study, the extent of resection was evaluated using the Simpson grade (SG) scale,5 which has been widely used to grade meningioma resection since 1957. Total resection, defined as removal of the whole tumor along with the attached dura mater and potentially affected bone, is unfeasible in many patients because of a high risk of brain injury, disrupting the blood supply to the central nervous system or simply because the lesion's location is inaccessible.6 The SG scale5 was therefore introduced into clinical practice as a parameter describing the extent of meningioma resection, which can be determined either intraoperatively by the surgeon or postoperatively by follow-up imaging. SG I denotes total resection and is associated with the lowest probability of recurrence. SG II-III denote gross total resections with the tumor itself removed completely but dura mater left in place with (SG II) or without (SG III) coagulation. SG IV denotes incomplete resection of the tumor, with a risk of recurrence almost 5 times higher than for SG I. Finally, SG V indicates that only a biopsy and/or decompression of the affected area were performed.7 MRI is used at most centers for accurate preoperative, intraoperative, and postoperative patient management, including assessing the extent of meningioma resection. A recent publication reported high concordance between SG classification and MRI assessment of tumor resection (up to 75%).8 Moreover, in prognostic value, the difference between SG IV and SG I-III is more significant than any other difference between SG categories, and SG IV resections are readily distinguished from those of lower grades through intraoperative assessment by a neurosurgeon. Consequently, despite the clear value of postoperative MRI for assessing the extent of resection, it is clear that clinically useful assessments can be obtained using the SG scale alone. Intraoperative MRI is also a powerful tool but can be problematically time consuming, and its practical utility may be limited by technical and economic factors, especially because it should ideally be applied in conjunction with other imaging methods and molecular analyses.9 However, perhaps the most important point relating to our study and Dr Wang's comments is that the inherent limitations of retrospective studies mean that evaluations based on follow-up MRI imaging are often simply unavailable in studies analyzing the prognostic and predictive value of novel genomic or proteomic biomarkers using archived tumor tissue samples.10-12 It therefore seems that evaluating the extent of tumor resection by MRI will be more viable in prospective studies than in retrospective studies based on follow-up data sets spanning 15 to 20 years.

Posterior-based resection of spinal meningiomas: an institutional experience of 141 patients with an average of 28 months of follow-up.

Spinal meningiomas pose unique challenges based on the location of their dural attachment. However, there is a paucity of literature investigating the role of dural attachment location on outcomes after posterior-based approach for spinal meningioma resection. The aim of this study was to investigate any differences in outcomes between dural attachment location subgroups in spinal meningioma patients who underwent posterior-based resection. This was a single-institution review of patients who underwent resection of a spinal meningioma from 1997 to 2017. Surgical, oncological, and neurological outcomes were compared between patients with varying dural attachments. Multivariate analysis was utilized. A total of 141 patients were identified. The mean age was 62 years, and 110 women were included. The sites of dural attachments were as follows: 16 (11.3%) dorsal, 31 (22.0%) dorsolateral, 17 (12.1%) lateral, 40 (28.4%) ventral, and 37 (26.2%) ventrolateral. Most meningiomas were WHO grade I (92.2%) and in the thoracic spine (61.0%). All patients underwent a posterior approach for tumor resection. There were no differences between subgroups in terms of largest diameter of tumor resected (p = 0.201), gross-total resection (GTR) or subtotal resection (p = 0.362), Simpson grade of resection, perioperative complications (p = 0.116), long-term neurological deficit (p = 0.100), or postoperative radiation therapy (p = 0.971). Cervical spine location was associated with reduced incidence of GTR (OR 0.271, 95% CI 0.108-0.684, p = 0.006) on multivariate analysis. The overall incidence of recurrence/progression was 4.6%, with no difference (p = 0.800) between subgroups. Similarly, the average length of follow-up was 28.1 months, with no difference between subgroups (p = 0.413). Posterior-based approaches for resection of spinal meningiomas are safe and effective, regardless of dural attachment location, with similar surgical, oncological, and neurological outcomes. Comparison of long-term recurrence rates between dural attachment subgroups is required.

Parasagittal Meningiomas: Prognostic Factors for Recurrence.

The term parasagittal meningioma applies to those tumors that are associated with the superior sagittal sinus (SSS), originating from the dura mater in close relation to the parasagittal wall or angle, with no intervening brain tissue, possibly extending to the dura of the convexity and/or falx cerebri.(Cushing et al., Meningiomas: their classification, regional behaviour, life history, and surgeical and results. Hafner, 1938) They make up about 20-30% of all meningiomas. There is a vast literature correlating the Simpson grade of resection with later recurrence. Frequent involvement of the superior sagittal sinus (SSS) by these tumors means that the optimal treatment recommended in the literature-complete resection, including of the dural base-is one of the most challenging.

Short-Term Results of Simpson Grade 2 Resection in Spinal Meningiomas

Spinal meningiomas are benign and slow-growing intradural tumors. Surgery is the choice of treatment. In this retrospective study, results of minimally invasive Simpson grade 2 resection and its impact on recurrence in 44 spinal meningiomas are reviewed. Clinical data of 44 cases who underwent surgery for spinal meningiomas between 2010 and 2020 have been reviewed retrospectively. Demographics, preoperative and postoperative clinical states, pathologic type, location of the meningioma relative to the spinal cord, resection amount of the tumor according to Simpson's grading scale, postoperative complications, recurrence rate, and correlation between preoperative and intraoperative data and recurrence were analyzed. The tumor was located in the thoracic spine in 31 cases, in the cervical spine in 12 cases, and in the lumbar spine in one case. Dural attachment of tumor was ventral to the spinal cord in 15 cases, lateral to the spinal cord in 15 cases, and posterior to the spinal cord in 14 cases. All cases underwent microsurgical Simpson grade 2 resection. Two cases were recurrent and reoperated. Recurrences were observed in cases younger than 18 years old, in cervical spines and in cases with long dural tails. Simpson grade 2 resection is safe and effective in spinal meningiomas. Patients younger than 18 year old, and those with cervical location and long dural tail may be under risk of recurrence after Simpson grade 2 resection.

Post Surgical Management of WHO Grade II Meningiomas: Our Experience, the Role of Gamma Knife and a Literature Review.

Purpose: Grade II meningiomas are rarer than Grade I, and when operated on, bear a higher risk of local recurrence, with a 5-year progression free survival (PFS) ranging from 59 to 90%. Radiotherapy (RT) or radiosurgery, such as Gamma Knife radiosurgery (GKRS) can reduce the risk of relapse in patients with residual disease, even if their role, particularly after gross total resection (GTR), is still under debate. Main goal of this study was to compare the outcomes of different post-surgical management of grade II meningiomas, grouped by degree of surgical removal (Simpson Grade); next in order we wanted to define the role of GKRS for the treatment of residual disease or relapse. Methods: from November 2016 to November 2020 all patients harboring grade II meningiomas, were divided into three groups, based on post-surgical management: (1) wait and see, (2) conventional adjuvant radiotherapy and (3) stereotactic GKRS radiosurgery. Relapse rate and PFS were registered at the time of last follow up and results were classified as stable, recurrence next to or distant from the surgical cavity. In the second part of the study we collected data of all patients who underwent GKRS in our Centers from November 2017 to November 2020. Results: A total of 37 patients were recruited, including seven patients with multiple meningiomas. Out of 47 meningiomas, 33 (70.2%) were followed with a wait and see strategy, six (12.7%) were treated with adjuvant radiotherapy, and 8 patients (17.0%) with adjuvant GKRS. Follow up data were available for 43 (91.4%) meningiomas. Within the wait and see group, recurrence rates differed based on Simpson grades, lower recurrence rates being observed in three Simpson I cases (30%) compared to twelve relapses (60%) in patients with Simpson grade II/III. Finally, out of the 24 meningiomas undergoing GKRS (8 residual and 16 recurrence), 21 remained stable at follow up. Conclusions: Gross total resection (GTR) Simpson II and III have a significantly worse outcome as compared to Simpson I. The absence of adjuvant treatment leads to significant worsening of the disease progression curve. Adjuvant radiotherapy, especially GKRS, provides good local control of the disease and should be considered as an adjuvant treatment in all cases where Simpson I resection is not possible.

Current Knowledge on Spinal Meningiomas-Surgical Treatment, Complications, and Outcomes: A Systematic Review and Meta-Analysis (Part 2).

Most of the knowledge on spinal meningiomas is extrapolated from their intracranial counterparts, even though they are considered separate entities. This review aimed to systematically summarize studies covering different aspects of spinal meningiomas and their management. Databases were searched for all studies concerning spinal meningiomas dating from 2000 and onwards. When possible, a meta-analysis was performed. Neurological outcomes of surgery were consistently favorable across studies, with a complication rate of 7.9% and 78.9% of the patients demonstrating good postoperative neurological function (McCormick score 1-2). The most relevant predictors of unfavorable outcomes were poor preoperative status, longer time from diagnosis to surgery, and surgery of recurrent tumors. The recurrence rate after surgery was estimated at 6%. Meta-analysis and/or survival analysis revealed that higher WHO grade (p &lt; 0.001), higher Simpson grade (p &lt; 0.001), ventral tumor location (p = 0.02), and male sex (p = 0.014) were all associated with higher odds of recurrence. However, the meta-analysis did not show any difference between Simpson grade 1 and grade 2 with respect to the odds of recurrence (p = 0.94). Surgery provided immediate and durable health-related quality-of-life improvement, as well as a high frequency of return to work. Spinal meningioma surgery is a relatively safe procedure with a low risk of tumor recurrence and high likelihood of favorable postoperative outcomes.

Pediatric meningioma with a Novel MAML2-YAP1 fusion variant: a case report and literature review

BackgroundPediatric meningioma with YAP1 fusion is a rare subset of meningiomas. Currently, there are lack of integrated clinical, radiological, and pathological features on this subset. Here, we reported a case of pediatric meningioma with a novel MAML2-YAP1 fusion variant and reviewed the relevant literature.Case presentationWe presented a case of 12-year-old boy with meningioma adjacent to the superior sagittal sinus and falx. Simpson grade II gross total resection was performed after diagnosis. Pathologically, he was diagnosed as WHO grade I meningothelial meningioma with rhabdoid features. A next-generation sequencing-based gene panel was performed to determine the molecular features for potential treatment, and a novel MAML2-YAP1 fusion break point was identified.ConclusionPediatric meningioma with the fusion of YAP1 and MAML2 genes is more likely to have pathological features of rhabdiod cells, which needs to be validated in large-scale studies for exploring better treatment under the integrated diagnosis.

Regrowth factors of WHO grade I skull base meningiomas following incomplete resection

The role of adjuvant radiation therapy following incomplete resection of WHO grade I skull base meningiomas (SBMs) is controversial, and little is known regarding the behavior of residual tumors. The authors investigated the factors that influence regrowth of residual WHO grade I SBMs following incomplete resection. From 2005 to 2019, a total of 710 patients underwent surgery for newly diagnosed WHO grade I SBMs. The data of 115 patients (16.2%) with incomplete resection and without any adjuvant radiotherapy were retrospectively assessed during a mean follow-up of 78 months (range 27-198 months). Pre-, intra-, and postoperative clinical and molecular factors were analyzed for relevance to regrowth-free survival (RFS). Eighty patients were eligible for analysis, excluding those who were lost to follow-up (n = 10) or had adjuvant radiotherapy (n = 25). Regrowth occurred in 39 patients (48.7%), with a mean RFS of 50 months (range 3-191 months). Significant predictors of regrowth were Ki-67 proliferative index (PI) ≥ 4% (p = 0.017), Simpson resection grades IV and V (p = 0.005), and invasion of the cavernous sinus (p = 0.027) and Meckel's cave (p = 0.027). After Cox regression analysis, only Ki-67 PI ≥ 4% (hazard ratio [HR] 9.39, p = 0.003) and Simpson grades IV and V (HR 8.65, p = 0.001) showed significant deterioration of RFS. When stratified into 4 scoring groups, the mean RFSs were 110, 70, 38, and 9 months for scores 1 (Ki-67 PI < 4% and Simpson grade III), 2 (Ki-67 PI < 4% and Simpson grades IV and V), 3 (Ki-67 PI ≥ 4% and Simpson grade III), and 4 (Ki-67 PI ≥ 4% and Simpson grades IV and V), respectively. RFS was significantly longer for score 1 versus scores 2-4 (p < 0.01). Tumor consistency, histology, location, peritumoral edema, vascular encasement, and telomerase reverse transcriptase promoter mutation had no impact on regrowth. Ki-67 PI and Simpson resection grade showed significant associations with RFS for WHO grade I SBMs following incomplete resection. Ki-67 PI and Simpson resection grade could be utilized to stratify the level of risk for regrowth.

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

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. 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. 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 1year 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. 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.

BIOM-52. DIAGNOSTIC POTENTIAL OF EXTRACELLULAR VESICLES IN MENINGIOMA PATIENTS

Abstract Standard monitoring after meningioma resection relies on serial MRI examinations, which are time-consuming, expensive and provide no information on molecular alterations that may indicate progression towards a more aggressive tumor. Extracellular vesicles (EVs) secreted by tumor cells play an important role in cell-cell communication, and tumor-derived EVs circulating in patient blood can serve as biomarkers. We investigated the potential role of plasma EVs in meningioma patients for tumor detection and determined whether EVs secreted by meningioma cells reflect epigenetic, genomic and proteomic alterations of original tumors. EV concentrations were quantified in patient plasma (n = 46). Short-term meningioma cultures were established (n = 26) and secreted EVs were isolated. Methylation and copy number profiling was performed using 850k arrays, and mutations were identified by targeted gene panel sequencing. Differential quantitative mass spectrometry was employed for proteomic analysis. We found that the levels of circulating EVs were significantly elevated in meningioma patients compared to healthy individuals, and that plasma EV concentrations correlated with malignancy grade and extent of peritumoral edema. Postoperatively, EV counts dropped to normal levels, and the magnitude of the postoperative decrease was associated with extent of tumor resection (Simpson grade). Methylation profiling of EV-DNA allowed correct tumor classification as meningioma in all investigated cases, and accurate methylation subclass assignment in nearly all cases. Copy number variations present in tumors, as well as tumor-specific mutations were faithfully reflected in meningioma EV-DNA. Proteomic EV profiling did not permit original tumor identification but revealed tumor-associated proteins such as desmoplakin that could potentially be utilized to enrich meningioma EVs from biofluids. In conclusion, elevated EV levels in meningioma patient plasma may aid in tumor diagnosis and assessment of treatment response. Meningioma EV-DNA mirrors genetic and epigenetic tumor alterations and facilitates molecular tumor classification.

Programmed death ligand 1 and tumor-infiltrating CD8+ T lymphocytes are associated with the clinical features in meningioma

ObjectiveTo investigate the expression of programmed death ligand-1 (PD-L1) and the levels of CD8+ tumor-infiltrating lymphocytes (TILs) in meningioma as well as determine the association between their levels and the clinical outcomes.MethodsWe performed a retrospective case-control study on 93 patients with meningioma. The patients showed tumor recurrence and were matched with the control patients without recurrence in their age, gender, admission time, tumor sites, tumor volume, peritumoral brain edema (PTBE), Simpson grade resection, WHO grade, postoperative radiotherapy, and the follow-up duration. We reviewed the clinical data of patients and performed immunohistochemistry analysis to investigate the PD-L1 expression and the levels of CD8+ TILs. Multivariate logistic regression was performed to analyze the association between clinical features and immune markers. The conditional logistic regression models were used to calculate the odds ratios (ORs) with 95% confidence intervals (CIs), and Kaplan–Meier analysis was performed to analyze tumor recurrence.ResultsTumor volume was correlated with the PD-L1 expression (P = 0.003, HR = 5.288, 95%CI, 1.786–15.651). PTBE served as an independent predictor of CD8+ TIL levels (P = 0.001, HR = 0.176, 95%CI 0.065–0.477). The levels of CD8+ TILs were associated with tumor recurrence (P = 0.020, OR = 0.325, 95%CI, 0.125–0.840).ConclusionTumor volume was associated with PD-L1 expression, and PTBE was an independent predictor of CD8+ TIL levels in meningioma. CD8+ TIL levels correlated with tumor recurrence in meningioma.

Integration of molecular pathology with histopathology to accurately evaluate the biological behaviour of WHO grade 2 meningiomas and patient prognosis.

A molecular pathological grading method was tested in WHO grade 2 meningiomas to judge whether this molecular grading can more accurately evaluate meningioma biological behaviour. The medical records and paraffin-embedded tissues of surgically resected WHO grade 2 meningioma patients in our department from January 1, 2010, to December 31, 2020, were collected. The molecular pathological risk grading suggested by Sahm et al. was adopted and the patients were graded as low, intermediate and high risk. Progression-free survival (PFS), malignant progression-free survival (MPFS) and overall survival (OS) were analysed. Univariate and multivariate analysis were performed to determine the relationship between molecular risk grading and patient survival. Of the 98 patients, 13 (13.2%) were graded as low risk, 63 patients (64.3%) were graded as intermediate risk, and 22 patients (22.4%) were graded as high risk. With increasing molecular risk grade, the rates of tumour recurrence, malignant progression and mortality increased significantly (P < 0.05). Multivariate analysis showed that molecular risk grading was negatively associated with PFS (HR 0.018, 95% CI 0.003-0.092), MPFS (HR 0.040, 95% CI 0.006-0.266) and OS (HR 0.088, 95% CI 0.016-0.472) (P < 0.01), and gross total resection (Simpson grade I-III) significantly prolonged PFS (HR 5.882, 95% CI 2.538-13.699) and OS (HR 2.611, 95% CI 1.117-7.299) (P < 0.05). Sahm et al.'s molecular risk grading can further refine the classification of WHO grade 2 meningiomas and more accurately evaluate their biological behaviour and patient prognosis.