Seizure semiology as a marker of spatial tumor complexity in insular gliomas: Implications for surgical planning

Objective Preoperative seizures are a common presenting feature of insular gliomas; however, their relationship to tumor spatial patterns and surgical planning remains insufficiently defined. This study evaluated whether seizure semiology is associated with the Integrated Insular Phenotype (IIP), an imaging-based classification reflecting tumor spatial complexity. Methods A retrospective single-center analysis included patients with insular gliomas presenting with preoperative seizures. Seizures were classified according to the ILAE 2017 framework. Tumors were categorized as IIP-L (local), IIP-H (hybrid), or IIP-M (multizonal) using predefined MRI criteria integrating zonal involvement and extrainsular extension. Associations between seizure type, epilepsy duration, and IIP were analyzed using comparative statistics and logistic regression adjusted for WHO grade and IDH status. Results Preoperative seizures occurred in 69.5% of the overall cohort and were predominantly focal. Among patients with focal seizures ( n = 110), the proportion of seizures with secondary generalization differed significantly across IIP groups ( χ 2 = 7.63; p = 0.022). Increasing IIP category was associated with a higher likelihood of secondary seizure generalization in univariate analysis (OR 1.92, 95% CI 1.13–3.27; p = 0.016). After adjustment for WHO grade and IDH status, IIP showed a borderline association with seizure propagation (OR 1.80, 95% CI 0.98–3.31; p = 0.047). Epilepsy duration also differed across phenotypes ( χ 2 = 12.05; p = 0.017), with shorter seizure histories more frequent in IIP-M tumors. Conclusions Focal seizure type, particularly secondary generalization, is associated with imaging-defined spatial phenotype in insular gliomas. Multizonal tumors demonstrate greater bilateral seizure propagation, reflecting broader cortical–subcortical network involvement and increased complexity. From a surgical perspective, seizure semiology may indicate multizonal extension and operative complexity during preoperative planning.