ID #1165 Subependymal Giant Cell Astrocytoma in a Non-Tuberous Sclerosis Child: A Case Report

Introduction

Subependymal giant cell astrocytoma (SEGA) is a benign intraventricular tumor most commonly associated with tuberous sclerosis complex (TSC). Sporadic SEGA without clinical or radiological features of TSC is rare and poses diagnostic and therapeutic challenges, particularly in resource-limited settings.

Case Illustration

A 5-year-old boy presented with recurrent nausea and vomiting due to increased intracranial pressure. Neuroimaging revealed a large intraventricular mass consistent with SEGA. Physical examinations showed no cutaneous stigmata of TSC. Serial neuroimaging demonstrated no cortical tubers or subependymal nodules. Systemic evaluation, including echocardiography and ophthalmologic examination, was unremarkable, and no relevant family history was identified. Based on the International TSC Consensus diagnostic criteria, the tumor was classified as sporadic (non-TSC) SEGA.

The clinical course was complicated by obstructive hydrocephalus requiring bilateral ventriculoperitoneal shunt placement. Subtotal tumor resection was performed, with histopathological confirmation of SEGA, followed by adjuvant radiotherapy. Post-radiotherapy magnetic resonance imaging showed a residual lobulated intraventricular mass measuring 4.2 × 4.2 × 3.9 cm. Everolimus therapy was initiated. Subsequent MRI 9 months after initiated therapy demonstrated further tumor regression to 2.4 × 2.3 × 2.0 cm, indicating a radiological response. Full-dose therapy was not feasible due to access and cost limitations, but the tumor showed radiologic reduction. The patient remained clinically stable and functionally independent.

Discussion

Sporadic SEGA may result from isolated somatic TSC2 mutations confined to tumor tissue, providing a biological rationale for mTOR inhibitor therapy despite the absence of systemic TSC features. In this case, everolimus was associated with sustained radiological tumor reduction. However, limited medication availability highlights real-world challenges in long-term SEGA management.

Conclusion

This rare case of sporadic SEGA showed a favorable response to everolimus, suggesting possible tumor-specific mTOR pathway activation, although molecular confirmation was not feasible due to limited resources. It highlights the diagnostic and therapeutic challenges of pediatric brain tumors in low- and middle-income countries.