Foraminal subependymal nodules and subependymal giant cell astrocytoma in children with tuberous sclerosis

Aims To characterize the growth patterns of foraminal subependymal nodules (fSENs) in children with tuberous sclerosis complex (TSC), and identify high‐risk periods and predictors of subependymal giant cell astrocytoma (SEGA) development. Method We retrospectively reviewed the records and brain imaging of children with TSC referred to our tertiary centre between 2012 and 2024. We included patients with one or more brain imaging undertaken before the age of 18 years, before neurosurgical or mTOR inhibitor treatment, and with one or more fSENs. fSEN volumes were measured and grouped according to their longitudinal volume evolution. Results We included 128 patients (male‐to‐female ratio 1.17:1) with 232 fSENs. Median age at first and last imaging was 3 years 2 months and 12 years respectively. Volume progression clustered fSENs into ‘non‐growing’ (71.0%, n = 149), ‘linear‐growing’ (19.5%, n = 41), or ‘non‐linear‐growing’ (9.5%, n = 20). The last group showed unpredictable growth up to 9 years. The initial fSEN volume (≥ 360mm 3 ) was an early predictor of further growth. Children under 5 years of age with an fSEN of 360mm 3 or greater and growth rate greater than 10mm 3 per year were the ‘high‐risk population’ when considering subependymal giant cell astrocytoma development. Interpretation Early volumetric assessment and identification of fSEN growth patterns may support a more predictive and personalized follow‐up in children with TSC.