Idiopathic Brain Herniations in Children: Clinical and Radiologic Correlations from a Retrospective Series

Objective Idiopathic brain herniations (IBH) are rare structural anomalies characterized by the protrusion of normal brain parenchyma into adjacent dural or venous compartments in the absence of trauma, surgery, mass effect, or intracranial hypotonia. Their clinical relevance in pediatric patients is not well understood. The aim of this study is to investigate the MRI characteristics and clinical associations of IBH in a pediatric population. Materials and methods We retrospectively analyzed 19 pediatric patients diagnosed with IBH on brain MRI at a tertiary radiology center between 2021 and 2025. Exclusion criteria included secondary herniation, systemic or congenital disease and poor image quality. Two board-certified neuroradiologists independently reviewed MRI findings, including herniation localization, laterality, and associated signal changes. Clinical data were extracted from patient records. Statistical analyzes were performed to evaluate correlations between hernias and neurological symptoms. Results The most frequent herniation site was the precuneal gyrus (52.6%), followed by the temporal lobe (36.8%). Temporal IBH was significantly associated with clinical seizures (p = 0.0009), whereas precuneus herniations were generally asymptomatic or associated with headache and dizziness. In two temporal IBH cases, MR venography revealed filling defects in the transverse sinus that mimicked venous thrombosis but proved to be benign. No significant correlation was found between IBH and age or gender of the patients. Conclusion Idiopathic brain herniations in children are not always incidental and may be associated with site-specific neurologic symptoms, particularly seizures in temporal hernias. Recognizing their imaging patterns is important to avoid misdiagnosis and unnecessary treatment. Awareness of IBH can improve diagnostic accuracy in pediatric neuroimaging practice.