Gamma-Knife Radiosurgery for Hypothalamic Hamartoma-Related Epilepsy

Purpose: Hypothalamic hamartoma (HH), a rare congenital disorder, can cause intractable epilep-sy and requires optimal surgical treatment. This study analyzed the clinical characteristics of HH and evaluated seizure outcomes and the safety of gamma-knife radiosurgery (GKS) in HH-related epilepsy to propose an optimal surgical treatment. Methods: We reviewed the medical records of 18 patients with HH treated at Samsung Medical Center (1997 to 2018), and analyzed their presenting symptoms, brain magnetic resonance im-aging (MRI) findings, treatment, and response. Results: The median diagnostic age was 3.2 years. The first presenting symptom was a seizure in six (33.3%), precocious puberty in five (27.8%), both symptoms in six (33.3%), and no symptoms in one patient who was diagnosed incidentally on brain MRI. All mixed and intrahypothalamic types except one had seizures (n=12), while all five parahypothalamic types presented only pre-cocious puberty. Eleven patients showed intractable epilepsy with medications and underwent surgical treatment (most commonly GKS). Eight patients underwent GKS, and two of them re-ceived repeated GKS for recurrent seizures. Six patients showed improved seizure control with GKS as the last treatment. Among them, two patients became seizure-free, and one patient had a decreased frequency of seizures after a single GKS. There was no adverse effect related to GKS. Conclusion: Intractable epilepsy was the most common indication for surgical treatment of pe-diatric HH. GKS was effective in controlling seizures in 75% of HH patients without any adverse effects. Repeated GKS could also be considered as a safe option for intractable and disabling seizures.