Abstracts

Hypothalamic hamartoma is often associated with gelastic epilepsy. The severity of the clinical picture is compounded by progressive cognitive and behavioral abnormalities. Due to the delicate site in which the tumor is located, stereotactic radiosurgery , a noninvasive procedure, was proposed.
We present 5 patients with hypothalamic hamartomas and refractory epilepsy, three girls and two boys between the ages of 3 and 13 years. Their neurological exams were unremarkable except for one patient who presented with polydactyly and imperforate anus, later diagnosed as Pallister Hall syndrome (PHS). In addition, abnormal behavior and cognitive impairment were evident in most of them.
All patients had gelastic seizures at some time; however only 3 had gelastic seizures when seen at our center. These either were followed immediately by drop attacks or progressed into complex partial attacks, occasionally evolving into a generalized or tonic-clonic seizure. Seizure frequency was usually high.
Interictal EEG showed focal sharp waves in two patients, and generalized slow spike wave complex, background slow and normal in the others. Ictal scalp EEG showed subtle diffuse changes. Magnetic Resonance imaging revealed hypothalamic hamartomas in all of them.
In 4 out of five cases presented, gamma knife radiosurgery was applied as a safe and noninvasive alternative to microsurgery in an attempt to obtain seizure control. Radiosurgical treatment was performed with the Gamma Knife model C system October 2001 for the first two, February 2002 for the third, March 2003 for the fourth. No surgical treatment was performed in the patient diagnosed as Pallister Hall syndrome.
Follow-up evaluations revealed a marked improvement in seizure frequency. One patient has been seizure free for the last 9 months (14mo follow up), and two of the others have had more than a 75% reduction in seizure frequency. The last patient had marked seizure control. Patients are currently able to attend public school.
No evidence of lesion from the radiosurgical therapy was seen in the last MRI.
We found that repetitive brief episodes of laughing were not suspected as possible epileptic events.
Gamma knife surgery is a potentially safe and valuable treatment modality for children with hypothalamic hamartomas and drug-resistant gelastic epilepsy.
The association between gelastic seizures and hypothalamic hamartomas is well known; patients with PHS must be identified and genetic counselling recommended.