Authors: Made Agus Mahendra Inggas , Kennytha Yoesdyanto , Edeline Samudra , Nathan Muliawan , Prudence Wirajaya , Elia Soediatmoko , Irhas ,

Abstract

Hypothalamic hamartoma (HH) is a rare congenital, non-neoplastic lesion of the hypothalamus, commonly presents with gelastic seizures, precocious puberty, or both. Gamma Knife radiosurgery (GKRS) has emerged as a minimally invasive treatment option, although long-term outcomes remain incompletely characterized. We report three pediatric patients with HH treated with single-session GKRS and evaluate their long-term clinical and radiological outcomes. All patients presented with gelastic seizures and precocious puberty, accompanied by varying degrees of cognitive, behavioral, or developmental impairment. Lesions were classified as Delalande type II–III, with target volumes ranging from 2.100 to 6.140 cm³. Following GKRS, seizure outcomes were heterogeneous. The first patient achieved substantial seizure control (Engel class ID) nearly four years after treatment, accompanied by cognitive improvement and reduction in antiseizure medication burden. The second patient experienced marked seizure improvement, including two years of complete remission (Engel class IA), but developed late seizure recurrence approximately five years after treatment (Engel class IIIB). The third patient demonstrated transient early improvement followed by seizure recurrence at 6-month follow-up (Engel class IVB). Radiological changes included transient lesion enlargement, central necrosis, and cystic evolution, which did not consistently correlate with clinical outcomes. Although responses varied, seizure improvement in two patients occurred despite minimal long-term volumetric reduction, supporting the hypothesis that GKRS may exert its effects through delayed neuromodulatory mechanisms rather than direct lesion shrinkage. These cases highlight the heterogeneous and delayed nature of clinical responses following GKRS, underscore the importance of long-term follow-up when evaluating treatment outcomes in pediatric HH.

Keywords: Hypothalamic hamartoma, gelastic epilepsy, gamma knife radiosurgery.