Radiosurgery of hypothalamic hamartomas

Hypothalamic hamartomas are relatively rare congenital tumors and present peculiar clinical symptoms such as convulsive and gelastic seizures, mental retardation, various abnormal behaviors as well as precocious puberty. We have treated 8 cases of symptomatic hypothalamic hamartomas with gamma knife surgery. There are 7 males and one female, ages ranging from 2 to 28 years (mean of 14.3 years). All the patients presented with convulsive and gelastic seizures, and some of them showed abnormal behavior and precocious puberty. At radiosurgery hypothalamic tumors, 8 to 22 mm in diameter (mean 13.5 mm), were treated with the mean maximum and marginal doses of 32.9 Gy and 18.5 Gy respectively. In general an entire tumor coverage was intended, but a few were partially covered, because of the tumor size as well as nearby sensitive structures like the optic nerve and the hypothalamus. With the mean follow-up of 53.7 months after the radiosurgery, generalized seizures were well controlled in 6 out of 8 cases, but gelastic seizures were not always controlled. In order to achieve an excellent seizure control and a favorable neurological outcome, a marginal dose of more than 18 Gy with total tumor coverage is definitely required. In conclusion, radiosurgery can play a role in treating hamartomas since neurological outcome and seizure control are apparently improved.