A Case Report of Deep-Seated Satellite Lesions in DNET : Is It a Tumor?

Dysembryoplastic neuroepithelial tumor (DNET) is a benign, pediatric brain tumor characterized by focal seizures, often progressing to drug-resistant epilepsy. Satellite lesions (SLs), small lesions adjacent to the main tumor mass typically embedded within normal parenchyma, are identified in approximately 50% of DNET cases and may contribute to recurrent seizures if not totally removed. However, detailed histopathological descriptions of SL remain limited to date. We report on an 8-year-old boy with medically intractable seizures and a T2 hyperintense mass in the left frontal lobe with smaller deep-seated SLs. The lesions were near totally removed, with deep-seated SLs successfully removed by performing a wider resection including the adjacent normal white matter with the aid of intraoperative ultrasonography, rather than through direct visual inspection. Histological analysis of deep-seated SLs showed homogeneous, typical DNET features identical to the main mass, including glioneuronal columns with oligodendrocyte-like cells and floating neurons within a mucoid matrix, confirming that deep-seated SLs are true tumors. In order to reduce the risk of recurrence, maximal safe resection of deep-seated SLs with the aid of ultrasonography might be helpful.