Location pattern of recurrence of fully resected grade 1 meningiomas.

OBJECTIVE: Meningiomas can lead to significant morbidity and mortality and have recurrence potential. While previous studies have focused on calculating recurrence risk, the precise location of the recurrence has not been delineated. This study aimed to investigate the spatial clustering pattern of recurrence relative to the original surgical bed for surgically treated Simpson Grade I-III, WHO Grade 1 meningiomas. METHODS: Patients diagnosed with grade 1 meningiomas and treated with surgical resection with subsequent recurrence were reviewed. Patient demographics, clinical outcomes, and radiographic characteristics were collected. Radiological images were analyzed to determine the location of recurrence relative to the initial tumor. We characterized recurrence as type A (within the surgical bed), type B (outside of the surgical bed, within 1 cm from the site), and type C (distal ≥ 1 cm of the resection site). RESULTS: Forty-two cases met the inclusion criteria. Twelve patients (29%) were male, and 30 (71%) were female. Median age at first treatment was 47 years, with 5.2 ± 3.4 years until recurrence. Recurrence rate was 54.7% at 5 years and 90.4% at 10 years. Twenty-eight patients (66.7%) had a type A recurrence, 11 (26.1%) had a type B recurrence, and 3 (7.1%) had a type C recurrence. CONCLUSIONS: Our series demonstrates that while lesions often recur within the original lesion site, a significant portion recurs beyond the surgical bed. This highlights the substantial possibility of recurrence outside the resection cavity for fully excised benign meningiomas, which may aid in understanding disease progression and in guiding adjuvant therapy.

Primary pituitary abscess in an adolescent female patient: case report, literature review, and operative video.

PURPOSE: Primary pituitary abscesses are extraordinarily rare lesions, especially in pediatric populations, with very few cases described in the literature. Here we review this rare condition and discuss its management. METHODS: We report a case of a previously healthy 12-year-old female patient who presented with vomiting and meningismus. We review the literature on pediatric patients presenting with pituitary abscesses and the described treatments. An operative video demonstrating our surgical technique is provided. RESULTS: Magnetic resonance imaging of the brain revealed a rim-enhancing, diffusion-restricting sellar lesion concerning for abscess. No sinus disease or other structural cause of intracranial infection was identified. An endoscopic transsphenoidal approach was used to visualize the endonasal structures, and microscopic guidance was used for evacuation of the abscess. Purulent material was drained immediately upon entry into the lesion. Tissue cultures grew Cutibacterium acnes. Postoperatively, the patient was hypocortisolemic but otherwise endocrinologically normal. She was discharged four days later on oral hydrocortisone and intravenous ceftriaxone without any neurologic deficit. CONCLUSION: To the best of our knowledge, this is the second report in the literature of a primary pituitary abscess due to C. acnes infection.

Demographics, Interests, and Quality of Life of Canadian Neurosurgery Residents.

BACKGROUND: Neurosurgical residents face a unique combination of challenges, including long duty hours, technically challenging cases, and uncertain employment prospects. We sought to assess the demographics, interests, career goals, self-rated happiness, and overall well-being of Canadian neurosurgery residents. METHODS: A cross-sectional survey was developed and sent through the Canadian Neurosurgery Research Collaborative to every resident enrolled in a Canadian neurosurgery program as of April 1, 2016. RESULTS: We analyzed 76 completed surveys of 146 eligible residents (52% response rate). The median age was 29 years, with 76% of respondents being males. The most popular subspecialties of interest for fellowship were spine, oncology, and open vascular neurosurgery. The most frequent self-reported number of worked hours per week was the 80- to 89-hour range. The majority of respondents reported a high level of happiness as well as stress. Sense of accomplishment and fatigue were reported as average to high and overall quality of life was low for 19%, average for 49%, and high for 32%. Satisfaction with work-life balance was average for 44% of respondents and was the only tested domain in which significant dissatisfaction was identified (18%). Overall, respondents were highly satisfied with their choice of specialty, choice of program, surgical exposure, and work environment; however, intimidation was reported in 36% of respondents and depression by 17%. CONCLUSIONS: Despite a challenging residency and high workload, the majority of Canadian neurosurgery residents are happy and satisfied with their choice of specialty and program. However, work-life balance, employability, resident intimidation, and depression were identified as areas of active concern.

Non-surgical transient cerebellar mutism-case report and systematic review.

INTRODUCTION: Transient cerebellar mutism has been well recognized in literature as a complication of posterior fossa tumor resection. It is marked by profound impairment of fluency, articulation, and modulation of speech, irritability and autistic features and typically resolves within days to months. Underlying pathophysiology is debated, but currently unknown. METHODS: We present a case of a child with similar clinical findings after cerebellitis, demonstration of diffuse cerebellar signal changes, swelling, and protruding tonsils at the level of foramen magnum. DISCUSSION: To support the hypothesis that this clinical syndrome may occur in a non-surgical context, we present a review of literature of non-surgical transient cerebellar mutism.

Operative Landscape at Canadian Neurosurgery Residency Programs.

Background Currently, the literature lacks reliable data regarding operative case volumes at Canadian neurosurgery residency programs. Our objective was to provide a snapshot of the operative landscape in Canadian neurosurgical training using the trainee-led Canadian Neurosurgery Research Collaborative. METHODS: Anonymized administrative operative data were gathered from each neurosurgery residency program from January 1, 2014, to December 31, 2014. Procedures were broadly classified into cranial, spine, peripheral nerve, and miscellaneous procedures. A number of prespecified subspecialty procedures were recorded. We defined the resident case index as the ratio of the total number of operations to the total number of neurosurgery residents in that program. Resident number included both Canadian medical and international medical graduates, and included residents on the neurosurgery service, off-service, or on leave for research or other personal reasons. RESULTS: Overall, there was an average of 1845 operative cases per neurosurgery residency program. The mean numbers of cranial, spine, peripheral nerve, and miscellaneous procedures were 725, 466, 48, and 193, respectively. The nationwide mean resident case indices for cranial, spine, peripheral nerve, and total procedures were 90, 58, 5, and 196, respectively. There was some variation in the resident case indices for specific subspecialty procedures, with some training programs not performing carotid endarterectomy or endoscopic transsphenoidal procedures. CONCLUSIONS: This study presents the breadth of neurosurgical training within Canadian neurosurgery residency programs. These results may help inform the implementation of neurosurgery training as the Royal College of Physicians and Surgeons residency training transitions to a competence-by-design curriculum.

Vertebral Artery Mobilization During Transcondylar Extreme Far Lateral Approach for Excision of Large Foramen Magnum Meningioma: 2-Dimensional Operative Video.

Foramen magnum meningiomas are challenging lesions owing to their proximity to the lower brainstem, vertebrobasilar system, and lower cranial nerves.1,2 Tumor size, origin, morphology, relationship to neurovascular structures, and bony anatomy determine the optimal surgical approach.2,3 Classically, far lateral approaches have been the workhorse approach to the foramen magnum. Variations of the far lateral including transcondylar and extended transcondylar (paracondylar), with or without transposition of the vertebral artery, are sometimes used for a more lateral approach to the brainstem and clivus. Here, we present a 60-year-old male patient presenting with a large foramen magnum meningioma. Preoperative workup includes computed tomography and MRI with angiography to assess for posterior circulation dominance, anatomic variants including posterior inferior cerebellar artery origin, venous, and bony anatomy.1,4 An extreme far lateral provides access anterior to the vertebral artery to extend exposure beyond the standard far lateral approach. This comprised transcondylar drilling, bony mobilization of the V3 Vertebral artery from C1 foramen transversarium, and dural mobilization of vertebral artery with a dural cuff at its site of dural entry. The patient tolerated the procedure, gross total resection was achieved, and the patient was discharged home. This video demonstrates in detail the steps of exposure, condylar drilling, vertebral artery transposition, and dural opening. These maneuvers can be difficult to conceptualize yet are key to successful extended transcondylar exposure. The patient gave informed consent for surgery and video recording. Institutional Review Board approval was deemed unnecessary.

Preoperative Corticosteroids Reduce Diagnostic Accuracy of Stereotactic Biopsies in Primary Central Nervous System Lymphoma: A Systematic Review and Meta-Analysis.

BACKGROUND AND OBJECTIVES: Despite general acceptance that corticosteroid therapy (CST) should be withheld before biopsy for suspected primary central nervous system lymphoma (PCNSL), there remains conflicting evidence surrounding the precise impact of preoperative CST on the histopathological diagnosis. The objective of this systematic review and meta-analysis was to describe and quantify the effects of preoperative CST on the diagnostic accuracy of biopsies for PCNSL. METHODS: Primary articles were screened from Ovid MEDLINE, Embase, Web of Science, and Scopus databases. Meta-analysis was performed for immunocompetent patients with histologically confirmed PCNSL. Subgroup and regression analyses were performed to assess the effects of biopsy type, CST duration, dose, and preoperative taper on the diagnostic accuracy. In addition, the sensitivity of cerebrospinal fluid (CSF) analyses for PCNSL was assessed. RESULTS: Nineteen studies, comprising 1226 patients (45% female; mean age: 60.3 years), were included. Preoperative CST increased the risk of nondiagnostic biopsy with a relative risk (RR) of 2.1 (95% CI: 1.1-4.1). In the stereotactic biopsy subgroup, the RR for nondiagnostic biopsy was 3.0 (95% CI: 1.2-7.5). CST taper, duration, and dose did not significantly influence diagnostic biopsy rates. The sensitivity of CSF cytology, including flow cytometry, for PCNSL was 8.0% (95% CI: 6.0%-10.7%). CONCLUSION: Our results suggest that preoperative CST reduces the diagnostic yield of stereotactic biopsies for PCNSL. We found no evidence that tapering CST before biopsy improves diagnostic rates. CSF analysis currently has a poor sensitivity for the diagnosis of PCNSL.

Molecular prognostication in grade 3 meningiomas and p16/MTAP immunohistochemistry for predicting CDKN2A/B status.

Background: The World Health Organization 2021 classification introduces molecular grading criteria for anaplastic meningiomas, including TERT promoter (TERTp) mutations and CDKN2A/B homozygous deletion. Additional adverse prognostic factors include H3K27me3 and BAP1 loss. The aim of this study was to explore whether these molecular alterations stratified clinical outcomes in a single-center cohort of grade 3 meningiomas. Additionally, we examined whether p16 and MTAP immunohistochemistry can predict CDKN2A/B status. Methods: Clinical and histopathological information was obtained from the electronic medical records of grade 3 meningiomas resected at a tertiary center between 2007 and 2020. Molecular testing for TERTp mutations and CDKN2A/B copy-number status, methylation profiling, and immunohistochemistry for H3K27me3, BAP1, p16, and methylthioadenosine phosphorylase (MTAP) were performed. Predictors of survival were identified by Cox regression. Results: Eight of 15 cases demonstrated elevated mitotic index (≥20 mitoses per 10 consecutive high-power fields), 1 tumor exhibited BAP1 loss, 4 harbored TERTp mutations, and 3 demonstrated CDKN2A/B homozygous deletion. Meningiomas with TERTp mutations and/or CDKN2A/B homozygous deletion showed significantly reduced survival compared to anaplastic meningiomas with elevated mitotic index alone. Immunohistochemical loss of p16 and MTAP demonstrated high sensitivity (67% and 100%, respectively) and specificity (100% and 100%, respectively) for predicting CDKN2A/B status. Conclusions: Molecular alterations of grade 3 meningiomas stratify clinical outcomes more so than histologic features alone. Immunohistochemical loss of p16 and MTAP show promise in predicting CDKN2A/B status.

Grade 3 meningioma survival and recurrence outcomes in an international multicenter cohort.

OBJECTIVE: Grade 3 meningioma represents a rare meningioma subtype, for which limited natural history data are available. The objective of this study was to identify demographics and pathologic characteristics, clinical and functional status outcomes, and prognostic factors in an international cohort of grade 3 meningioma patients. METHODS: Clinical and histopathological data were collected for patients treated at 7 sites across North America and Europe between 1991 and 2022. RESULTS: A total of 103 patients (54% female, median age 65 [IQR 52, 72] years) were included. Sixty-seven (65%) patients had de novo grade 3 lesions, whereas 29 (28%) had malignant transformations of lower-grade meningiomas. All patients underwent initial resection of their tumor. Patients were followed for a median of 46 (IQR 24, 108) months, during which time there were 65 (73%) recurrences and 50 (49%) deaths. The 5-year overall survival (OS) and progression-free survival (PFS) rates were 66% (95% CI 56%-77%) and 37% (95% CI 28%-48%), respectively. Age ≥ 65 years and male sex were independent predictors of worse OS and PFS in multivariate regression analysis, while postoperative radiotherapy was independently associated with improved OS. Karnofsky Performance Status (KPS) remained stable relative to baseline over 5 years postdiagnosis among participants who were alive at the end of the follow-up period. CONCLUSIONS: This large multicenter study provides insight into the longitudinal outcomes of grade 3 meningioma, with respect to recurrence, survival, and functional status. This study affirms the survival benefit conferred by radiotherapy in this population and suggests good functional status outcomes for patients surviving to 5 years postoperatively.

Corrigendum: Grade 3 Meningioma Survival and Recurrence Outcomes in an International Multicenter Cohort.

[This corrects the article DOI: 10.1055/s-0044-1779888.].

Molecular classification to refine surgical and radiotherapeutic decision-making in meningioma.

Treatment of the tumor and dural margin with surgery and sometimes radiation are cornerstones of therapy for meningioma. Molecular classifications have provided insights into the biology of disease; however, response to treatment remains heterogeneous. In this study, we used retrospective data on 2,824 meningiomas, including molecular data on 1,686 tumors and 100 prospective meningiomas, from the RTOG-0539 phase 2 trial to define molecular biomarkers of treatment response. Using propensity score matching, we found that gross tumor resection was associated with longer progression-free survival (PFS) across all molecular groups and longer overall survival in proliferative meningiomas. Dural margin treatment (Simpson grade 1/2) prolonged PFS compared to no treatment (Simpson grade 3). Molecular group classification predicted response to radiotherapy, including in the RTOG-0539 cohort. We subsequently developed a molecular model to predict response to radiotherapy that discriminates outcome better than standard-of-care classification. This study highlights the potential for molecular profiling to refine surgical and radiotherapy decision-making.

Intraoperative and postoperative complications for repeat high-grade glioma resections with concurrent chemotherapy: patient series.

BACKGROUND: High-grade gliomas are aggressive primary brain tumors, the most common of which is glioblastoma multiforme. Despite advances in treatment, the prognosis for these patients remains poor. The most common chemotherapeutic agents used in the treatment of this pathology include temozolomide (TMZ), procarbazine, lomustine, and vincristine. It is unclear whether chemotherapy should be held during resection for high-grade gliomas, because the perioperative risk profile is not clearly defined. OBSERVATIONS: The authors report a case series of 18 surgeries to investigate the effects of concurrent TMZ and lomustine chemotherapy on surgical complications in patients undergoing repeat resection for recurrent high-grade gliomas. The authors found no postoperative infections, self-limiting postoperative complications, or excessive intraoperative blood loss and found one intraoperative complication. LESSONS: There may not be a need to pause TMZ and lomustine chemotherapy during recurrent resections for high-grade gliomas, and continuing these medications throughout the perioperative period may be appropriate. This case series suggests that patients receiving TMZ and lomustine chemotherapy who need a repeat resection for recurrent high-grade gliomas should consider remaining on their chemotherapy regimen because it has been shown in the literature to improve recurrence-free survival time.

Correlation of Pituitary Descent and Diabetes Insipidus After Transsphenoidal Pituitary Macroadenoma Resection.

BACKGROUND: Endoscopic transsphenoidal surgery remains the technique of choice for resection of pituitary adenoma. Postoperative diabetes insipidus (DI) is most often transient and observed in 1.6% to 34% of patients, whereas permanent DI has been reported in 0% to 2.7% of patients. The proposed mechanism was the transduction of traction forces exerted by the surgeon on the descended diaphragma sellae and through the pituitary stalk. OBJECTIVE: To quantify and correlate the degree of pituitary gland descent with postoperative DI. METHODS: Of 374 patients who underwent transsphenoidal resection of a pituitary adenoma between 2010 and 2020 at our institution, we report a cohort of 30 patients (Group A) DI. We also report a matched cohort by tumor volume of 30 patients who did not develop DI (Group B). We quantified the tension on the pituitary stalk by calculating pituitary descent interval (PDI) by comparing preoperative and postoperative position of the pituitary gland and using Pythagoras' formula where , with craniocaudal (CC) and anterior-posterior (AP) representing measurements of pituitary translation in respective directions after resection. RESULTS: Patients who developed DI had significantly greater pituitary gland translations in the craniocaudal (23.0 vs 16.3 mm, P = .0015) and anteroposterior (2.4 vs 1.5 mm, P = .0168) directions. Furthermore, Group A had a statistically greater PDI, which was associated with development of DI (23.2 vs 16.6 mm, P = .0017). CONCLUSION: We were able to quantify pituitary descent and subsequent tension on the pituitary stalk, while also associating it with development of postoperative DI after pituitary adenoma resection.

Supraclinoid Internal Carotid Artery Dolichoectasia Causing Compression of the Prechiasmatic Optic Nerve.

BACKGROUND AND IMPORTANCE: Intracranial arterial dolichoectasia (or dilatative arteriopathy) is characterized by abnormal elongation, tortuosity, or increase in diameter of at least one of the main cerebral vessels. Dolichoectasia can be found incidentally or can present with cranial neuropathies (including vision loss) or stroke. Here, we describe the presentation and open surgical treatment of a patient with dolichoectasia of the intracranial internal carotid artery (ICA) causing monocular vision loss. CLINICAL PRESENTATION: A 73-year-old man presented with several months of progressive monocular vision loss and was found to have dolichoectasia of the supraclinoid ICA and subsequently underwent microsurgical decompression of the overlying affected optic nerve. The patient's postoperative convalescence was uncomplicated, and he had improvement in his right-sided monocular vision loss after surgery. CONCLUSION: We present the case of a patient with dolichoectasia of the supraclinoid ICA causing compression of the optic nerve with resultant monocular vision loss. Timely microvascular decompression proves to be an effective technique for vision preservation in the setting of this rare pathologic entity.

Fractionated radiotherapy for surgically resected intracranial meningiomas: A multicentre retrospective cohort study.

BACKGROUND: Aside from surgical resection, the only standard of care treatment modality for meningiomas is radiotherapy (RT). Despite this, few studies have focused on identifying clinical covariates associated with failure of fractionated RT following surgical resection (fRT), and the timing of fRT following surgery still remains controversial (adjuvant versus salvage fRT). We assessed the outcomes of the largest, multi-institutional cohort of surgically resected meningiomas treated with subsequent adjuvant and salvage fRT to identify factors associated with local freedom from recurrence (LFFR) over 3-10 years post-fRT and to determine the optimal timing of fRT. METHODS: Patients with intracranial meningiomas who underwent surgery and fRT between 1997 and 2018 were included. Primary endpoints were radiographic recurrence/progression and time to progression from the completion of fRT. RESULTS: 404 meningiomas were included for analysis. Of these, 167 (41.3%) recurred post-fRT. Clinical covariates independently associated with worse PFS post-fRT included receipt of previous RT to the meningioma, having a WHO grade 3 meningioma or recurrent meningioma, the meningioma having a higher MIB1-index or brain invasion on pathology, and older patient age at diagnosis. Subgroup analysis identified higher MIB1-index as a histological factor associated with poorer LFFR in WHO grade 2 meningiomas. 179 patients underwent adjuvant RT shortly after surgery whereas 225 patients had delayed, salvage fRT after recurrence/progression. Following propensity score matching, patients that underwent adjuvant fRT had improved LFFR post-fRT compared to those that received salvage fRT. CONCLUSION: There is a paucity of clinical factors that can predict a meningioma's response to fRT following surgery. Adjuvant fRT may be associated with improved PFS post-fRT compared to salvage fRT. Molecular biomarkers of RT-responsiveness are needed to better inform fRT treatment decisions.

The Unified Visual Function Scale Assessments Show Inter- and Intraobserver Agreement and Correlate with Patient Quality of Life in Skull Base Parasellar Tumors.

Introduction The authors have previously described the Unified Visual Function Scale (UVFS). Here, we assessed intra- and interobserver reliability of the scale, and investigated correlations with patient quality of life (QoL). Methods Eight healthcare practitioners independently applied the UVFS in 20 representative cases from our parasellar meningioma series. Scoring was compared with consensus grades assigned by lead authors. Inter- and intraobserver agreement was measured using intraclass correlation coefficient (ICC), Fleiss's κ, and Cohen's κ, respectively. Patient QoL was assessed Visual Function Questionnaire 25 (VFQ-25) or Activities of Daily Vision Scale (ADVS), and correlated with UVFS grades for each eye. Results The interobserver ICC was 0.734 (95% confidence interval [CI]: 0.652-0.811), with Fleiss's κ of 0.758, 0.691, and 0.899 for grades A, B, and C, respectively. The intraobserver ICC was 0.758 (95% CI: 0.638-0.872), and Fleiss's κ was 0.604, 0.268, and 0.910 for grades A, B, and C respectively. The Cohen's κ for agreement between UVFS category grades and consensus grades was 0.816 (95 CI: 0.698-0.934). Survey response rate was 51% (27/53). The UVFS demonstrated strong correlation with VFQ-25 subdivisions general vision ( r = 0.7712), near activities ( r = 0.7262), peripheral vision ( r = 0.6722), and driving ( r = 0.6608), and also demonstrated strong correlation with the overall ADVS score ( r = 0.5902). Conclusion This study shows that the UVFS is valid within a small subset of observers, and accurately reflects patient QoL. It is robust and practical, which make it suitable for broad implementation.

Outcomes and surgical nuances in management of giant pituitary adenomas: a review of 108 cases in the endoscopic era.

OBJECTIVE: Giant (maximum diameter ≥ 4 cm) pituitary macroadenomas are complex tumors that require resection for decompression of optic nerves, relief of mass effect, and symptom improvement. Given the lack of surgical accessibility, the lateral extent of the lesions, and the invasion of the cavernous sinus, management presents a significant challenge. Transsphenoidal, transcranial, and combined approaches have been viable options for resection. The authors present their findings from a large series of patients to characterize giant pituitary adenomas, document outcomes, and outline surgical nuances in resection of these tumors. METHODS: The authors reviewed 887 consecutive patients who underwent resection of pituitary adenomas at a single institution. From this group, 108 patients with giant pituitary adenomas who underwent resection between January 1, 2002, and December 31, 2020, were identified for inclusion in the study. The patient demographics, clinical presentation, tumor imaging characteristics, surgical approaches, and postoperative outcomes were analyzed using descriptive statistics. RESULTS: The mean preoperative tumor diameter in this cohort was 4.6 ± 0.8 cm, with a mean volume of 25.9 ± 19.2 cm3. Ninety-seven patients underwent transsphenoidal approaches only, 3 underwent transcranial resection, and 8 patients underwent a combined approach. Gross-total resection was achieved in 42 patients. Tumor stability without a need for additional therapy was achieved in 77 patients, with 26 patients undergoing subsequent adjuvant radiotherapy. Among 100 patients with sufficient follow-up, 14 underwent adjuvant therapy-repeat operation and/or adjuvant radiation therapy-because of recurrence or tumor progression. Six patients with recurrence were observed without additional treatment. Overall, the morbidity associated with removal of these lesions was 11.1%; the most common morbidities were cerebrospinal fluid leak (5 patients, 4.6%) and hydrocephalus (4 patients, 3.7%). One death due to postoperative pituitary apoplexy of the residual tumor and malignant cerebral edema occurred in this cohort. CONCLUSIONS: Giant pituitary tumors still represent a surgical challenge, with significant morbidity. Gross-total resection occurs in a minority of patients. Surgical goals for removal of giant pituitary tumors should include attempts at removal of most tumor tissue to minimize the risk of residual tumor apoplexy by tailoring the approach along the major axis of the tumor. Experience with both transsphenoidal and multiple transcranial techniques is necessary for minimizing complications and improving outcomes.

Microsurgical Excision of Ruptured Lenticulostriate Artery Aneurysm.

Lenticulostriate artery aneurysms are uncommon lesions, usually found in adults after hemorrhage. Despite their challenging location, mortality rates after initial hemorrhage are favorable. Securing the hemorrhage source is critical but may be complicated by lesional compression or thrombosis on posthemorrhage vascular imaging. We present key steps in the diagnosis and surgical management of a ruptured lenticulostriate aneurysm (Video 1). A healthy 18-year-old patient with prior intermittent prescription amphetamine use presented after acute severe headache onset while weight lifting. On examination, he had trace left upper extremity drift and weakness but was otherwise neurologically intact. A head computed tomography demonstrated a 2.9 × 2.6 × 1.7-cm right basal ganglia intraparenchymal hemorrhage, with trace subarachnoid hemorrhage in the basal cisterns. Secondary imaging including magnetic resonance imaging, computed tomography angiogram, and digital subtraction angiogram was negative for underlying lesions. After an uneventful recovery, a 4-month magnetic resonance angiogram and subsequent digital subtraction angiography demonstrated a 2.7-mm right lenticulostriate aneurysm in the area of the prior hemorrhage. Treatment was recommended to prevent a rehemorrhage, with the safety of local vessel sacrifice presumed based on prior local tissue damage. Microcatheterization was unsuccessful. A right frontotemporal craniotomy for transsylvian, transinsular microsurgical aneurysm excision was performed, with image guidance used for the insular entry site. The patient was discharged home neurologically intact on postoperative day 2. At 1-year follow-up, there were no new or recurrent vascular lesions on imaging. Delayed imaging is critical to identify initially occult cerebrovascular lesions after hemorrhage. The transsylvian, transinsular approach provides safe access to the basal ganglia region in selected patients.

The impact of brain invasion criteria on the incidence and distribution of WHO grade 1, 2, and 3 meningiomas.

BACKGROUND: In 2016 brain invasion was added as a standalone diagnostic criterion for Grade 2 meningiomas in the WHO Classification of Brain Tumors. The aim of this study was to compare the incidence and distribution of meningiomas, and agreement, between the 2007 and 2016 WHO criteria. METHODS: All cases of intracranial meningiomas diagnosed between 2007 and 2020 at a tertiary care academic hospital were identified. The incidence of each meningioma grade in the WHO 2007 and WHO 2016 cohorts were compared. Additionally, each case in the 2007 cohort was re-graded according to the WHO 2016 criteria to determine the intra-class correlation (ICC) between criteria. RESULTS: Of 814 cases, 532 (65.4%) were in the 2007 WHO cohort and 282 (34.6%) were in the 2016 WHO cohort. There were no differences in the distribution of meningioma grades between cohorts (P = .11). Incidence rates were: 75.0% vs. 75.2% for Grade 1, 22.7% vs. 24.5% for Grade 2, and 2.3% vs. 0.4% for Grade 3, for the 2007 and 2016 cohorts, respectively. Upon re-grading, 21 cases (3.9%) were changed. ICC between original and revised grade was 0.92 (95% CI: 0.91-0.93). Amongst Grade 2 meningiomas with brain invasion, 75.8% had three or more atypical histologic features or an elevated mitotic index. CONCLUSIONS: Including brain invasion as a standalone diagnostic criterion for Grade 2 meningiomas had minimal impact on the incidence of specific meningioma grade tumors. There is strong agreement between the 2007 and 2016 WHO criteria, likely due to cosegregation of grade elevating features.