Stereotactic Radiation for the Treatment of a Hypothalamic Hamartoma Accompanied with Intractable Seizures
Authors: Arita Kazunori , Kurisu Kaoru , Iida Koji , Hanaya Ryosuke , Akimitsu Tomohide , Hibino Seiichiro , Pant Basant , Hamasaki Masatake , Shinagawa Shoji 
Published: August 2009

Purpose: Seizures caused by hypothalamic hamartomas are usually difficult to control. Surgical removal of the lesion has been reported to be an effective therapy to control the seizures. However, surgical treatment can potentially damage the cranial nerves or the hypothalamus.

Case Report: This is a report of a patient who had intractable epilepsy due to an inaccessible hypothalamic hamartoma and was subsequently treated with stereotactically directed irradiation by using a gamma‐knife unit. This 25‐year‐old man had a history of intractable gelastic and tonic‐clonic seizures for the last 23 years. His seizures started with a transient atony of his trunk and extremities at age 6 months. Soon they became associated with gelastic attacks with utterances followed by short generalized tonic‐clonic seizures and prolonged postictal drowsiness. He was referred to our department in August 1995, just after a seizure‐related car accident. Usually, the seizures were generalized tonic‐clonic convulsions following a gelastic attack, occurring 3–6 times a month while taking anticonvulsants such as carbamazepine (CBZ; 1,200 mg), valproate (VPA; 1,800 mg), and zonisamide (ZNS; 600 mg) daily. He also had automatic seizures presenting as oral automatisms, vomiting, and spitting, and these occurred once or twice a month. The blood levels of these drugs were above the minimal effective concentrations, There was no evidence of precocious puberty or any apparent mental retardation. Electroencephalography (EEG) revealed diffuse and dysrhythmic slow background activities and sporadic spike or spike‐and‐wave activities preferentially in the left frontal and parietal leads. Video‐EEG monitoring showed generalized tonic‐clonic seizures after a transient laughing attack accompanied by diffuse spike‐and‐wave bursts, which did not show any laterality. The current magnetic resonance imaging (MRI) as well as the MRI performed 30 months ago demonstrated a nonenhancing and non‐progressive spherical mass ‐10 mm in diameter on the right side at the floor of the third ventricle. The lesion was irradiated with 36 Gy to the center and 18 Gy (50% isodose line) to the margin through a 4–mm and an 8–mm collimator. Two months after the irradiation, the frequency of the seizure attacks transiently increased. However, he has not had any seizures since 3 months after the therapy. Antiepileptic drugs (AEDs) have been reduced since 1 year after the irradiation. The MRI performed 1 year after the irradiation demonstrated a complete disappearance of the lesion. The patient has been seizure free for the last 17 months, with no neurologic or endocrinologic complications. The MRI examination 12 months after the irradiation showed a complete disappearance of the lesion.

Conclusions: Stereotactic irradiation by‐,using a gamma‐knife unit appears to be a promising therapeutic option for surgically inaccessible hypothalamic hamartomas associated with intractable seizures.