John Ta-Hsiang Tsiang

BACKGROUND AND OBJECTIVES: Simpson grading remains the most widely used clinical classification of extent of resection in meningioma surgery, yet its relevance in modern neurosurgical practice remains debated. The aim was to evaluate whether Simpson grading is associated with recurrence risk after gross total resection (GTR) of intracranial meningiomas within the context of tumor biology and anatomic location. METHODS: We analyzed 4074 patients undergoing GTR (Simpson grades 1-3) for primary intracranial meningioma, compiling data from 42 institutions worldwide. Cumulative incidence of recurrence was estimated using Aalen-Johansen methods. Multivariable inverse probability of censoring weighted logistic regression models were used to estimate adjusted recurrence risks at 5 and 10 years, adjusting for age, sex, World Health Organization (WHO) grade, Ki-67 proliferation index, and healthcare system setting. RESULTS: Higher Simpson grades were consistently associated with increased recurrence risk in WHO-1 and WHO-2. Among WHO-1, Simpson grade 2 had more than twice the recurrence odds compared with grade 1 at 5 years, whereas grade 3 showed even higher odds ratio of 3.47 (95% CI, 1.98-6.08). Similar patterns were observed in WHO-2 tumors. Interaction analyses suggested that differences between Simpson grades increase with higher Ki-67 proliferation indices. The prognostic significance of Simpson grade varied across anatomic locations, with clear associations observed for convexity and skull-base meningiomas, but limited relevance for parasagittal/falx meningiomas irrespective of WHO grade. CONCLUSION: Simpson grading remained strongly associated with recurrence after GTR. These findings suggest that the extent of dural and bony clearance remains clinically relevant; however, Simpson grading should be contextualized within tumor biology and anatomic constraints. Future recurrence models integrating molecular and surgical variables may refine prognostic frameworks rather than current standalone classification systems.

Purpose: Recurrence risk estimates underpin meningioma research, including molecular classification and clinical trial benchmarking, yet are often based on retrospective or historical data. The aim of this study was to assess the variation of recurrence risk estimates across calendar periods, WHO classification editions, geographical settings, and healthcare systems.thetermine Methods: We analyzed 4,111 patients with primary WHO-1/-2 meningiomas from 31 centers in 15 countries (1990–2019). Recurrence was defined according to local radiological assessment. The 5- and 10-year recurrence risks were estimated using regression standardization with inverse probability of censoring weights, adjusting for key clinical, surgical, and histopathological variables. Results: Recurrence risk estimates varied across all domains examined. More recent calendar periods were associated with higher predicted recurrence risk, particularly for WHO-2 at 5 years (e.g., ≥ 2013 vs. ≤ 2007: RR 1.60, 95% CI 1.19–2.01). Differences were also observed across healthcare systems and geographical settings despite adjustment. In contrast, recurrence risk estimates were broadly comparable between WHO classification editions (2007 vs. 2016). Cohort-level visualization revealed substantial heterogeneity in follow-up duration, inclusion patterns, and recurrence detection. Conclusions: Recurrence risk estimates are not stable across time or settings and are influenced by several patterns, particularly data accrual patterns. Recurrence events are inherently “locked” to the historical context in which they were detected, which may have important implications for developing molecular classifiers using retrospective specimens and clinical trials relying on benchmark established in historical settings. We propose transparent visualization of observational cohort composition and individual-level event timing to improve interpretability and comparability.

Purpose: The Ki-67 proliferation index (Ki-67 PI) has been associated with meningioma recurrence, yet its clinical utility remains debated. Whether Ki-67 PI provides prognostic information across subgroups defined by both WHO grade and extent of resection remains to be investigated. Methods: We analyzed 5,050 patients with intracranial meningiomas from the international PERNS cohort (42 centers, diagnosed between 1989–2019) who underwent surgical resection without postoperative radiotherapy. Ki-67 PI prognostic accuracy was assessed up to 10 years postoperatively by using ROC analyses and estimating its association with the risk of recurrence. Results: Results demonstrated that the prognostic value of Ki-67 PI differed by subgroups defined by WHO grade and Simpson grade. For patients with the same Simpson grade (1–3), the predictive accuracy of Ki-67 PI for 10-year recurrence risk was stronger in WHO-2 than in WHO-1. Within WHO-1 and WHO-2 meningiomas, the predictive accuracy of Ki-67 PI increased with higher Simpson grade (1–3). However, no predictive value was observed in Simpson grade 4 resections regardless of WHO grade. Conclusion: These findings highlight that Ki-67 PI should be interpreted in the context of both WHO grade and extent of resection, and, if done so, may offer potential value to refine individualized surveillance strategies in meningioma patients with gross total resection in the initial 10-year postoperative timeframe. Findings cannot be extrapolated beyond 10 years, which may be particularly relevant for WHO-1 tumors with low Ki-67 PI and Simpson grade 1 resection.

Background: Autoimmune hypophysitis (AH), an uncommon inflammatory disorder of the pituitary gland, involves immune cell infiltration into pituitary tissue and often occurs concurrently with systemic autoimmune diseases. Although Hashimoto’s thyroiditis, systemic lupus erythematosus, and IgG4-related disease have been associated with AH, rheumatoid arthritis (RA)-associated AH remains exceedingly rare, particularly in seropositive cases. Clinical and imaging characteristics of AH mimic a wide range of infectious, neoplastic, and infiltrative pathologies. Biopsy remains the gold standard for definitive diagnosis, though it is rarely pursued. Methods: A retrospective chart review was performed to obtain the details regarding patient history, histopathological findings, and treatment course. Results: This rare case of biopsy-proven AH involved a 46-year-old female with seropositive RA. The patient presented with progressive headaches, small scotomas in both visual fields, and multiple endocrinopathies including central hypothyroidism and adrenal insufficiency. Magnetic resonance imaging revealed an infiltrative, contrast-enhancing suprasellar lesion. Surgical intervention was pursued for biopsy and debulking. Histopathology demonstrated pituitary tissue infiltrated by a heterogeneous population of inflammatory cells without evidence of well-formed granulomas. In the context of positive rheumatoid factor (RF) and anticyclic citrullinated peptide antibodies, the diagnosis of RA-associated AH was favored. The patient was treated with azathioprine with resolution of her headaches and scotomas and radiographic improvement. To our knowledge, this case represents the first biopsy-proven example of seropositive RA-associated AH. Conclusion: This case underscores the importance of maintaining a broad differential diagnosis when evaluating pituitary lesions, especially in patients with systemic autoimmune disorders, and highlights the role of tissue diagnosis and decompression in a symptomatic patient with a suprasellar lesion resulting in mass effect.

We present a case of a meningo-meningeal arteriovenous fistula (MMAVF) discovered immediately following middle meningeal artery (MMA) microparticle embolization for the treatment of an acute subdural hematoma (SDH). An elderly patient presented with an SDH found during stroke workup. MMA embolization was elected due to his need for therapeutic anticoagulation. During the procedure, multiple MMAVFs appeared after microparticle embolization of the distal MMA branches. We aborted further microparticle embolization and performed coil embolization of the MMA trunk with cessation of flow. No clinical complication was noted postoperatively and no post-procedure hemorrhage was seen. Review of literature suggests that this phenomenon may be associated with microparticle embolization. We hypothesize the cause to be vessel rupture due to barotrauma during manual injection via the microcatheter. As MMA embolization becomes more common, this complication may become more recognized.

BACKGROUND AND OBJECTIVES: Symptomatic hydrocephalus (HCP) requiring cerebrospinal fluid diversion by shunting is routinely performed through ventriculoperitoneal or ventriculoatrial (VA) shunting. The optimal method of distal catheter placement for a VA shunt is not well defined. We detail a novel surgical technique for VA shunt placement using intraoperative digital subtraction angiography (DSA). METHODS: The aim of this single-institution, retrospective review was to describe a unique technique of distal catheter placement in a series of the initial 50 consecutive adult patients who underwent VA shunt placement with DSA at our institution between 2021 and 2024. Detailed procedural techniques and outcomes are described. RESULTS: Accurate surgical placement of the distal VA shunt was achieved in 48 patients (96%). Five patients required shunt revisions for delayed shearing of distal catheter (1), suboptimal distal catheter placement (3), and suboptimal proximal catheter placement (1). Four instances of post-VA shunt bacteremia were found when patients were routinely cultured for febrile episodes; all completed appropriate antibiotic course, and none resulted in meningitis or required shunt revision. Kaplan-Meier analysis demonstrated overall VA shunt success of 92% at 3 years after initial surgery. CONCLUSION: This series of 50 consecutive patients demonstrated use of intraoperative DSA yields safe and accurate placement VA shunts with acceptable long-term outcomes. As more neurosurgeons have endovascular training, this surgical technique may be more readily adopted.