Stereotactic radiosurgery for hypothalamic hamartomas.

Hypothalamic hamartomas are nonneoplastic lesions often characterized by central precocious puberty and gelastic epilepsy. Due to the delicate location surgery is often unsuccessful and associated with considerable risks. In the presented series, Gamma Knife radiosurgery was applied. Four cases (aged between 5-13 years) who presented with medically intractable gelastic epilepsy and increasing secondary generalization, abnormal behaviour and precocious puberty (3 cases) are reported. Hypothalamic hamartomas sized 11-17 mm had been diagnosed by MR imaging. Radiosurgical treatment was performed in general anaesthesia with margin doses of 12-14 Gy to the 50-90% isodoses covering volumes of 600-2300 mm3. After follow-up periods of 12 to 68 months, a continuing decrease both in seizure frequency and intensity was noted (outcome according to Engel: II a (3 cases) and III a (1 case)). All patients are socially reintegrated. MR imaging did not reveal significant changes concerning the size of the lesions. Gamma Knife radiosurgery can be an effective and safe alternative treatment modality for HH capable of achieving good seizure control and improving behavioural disorders in selected cases.