Hemimegalencephaly in a patient with a neurocutaneous syndrome.

A 5-year-old girl with a history of hypomelanosis of Ito and intractable epilepsy was evaluated for possible resective surgery. Magnetic resonance imaging showed an enlarged right hemisphere, whereas electrographic seizures were arising from the right hemisphere or had a generalized onset. The patient was believed to be a good candidate for hemispherectomy, but the family was hesitant and started a modified Atkins diet. Her seizure control has improved, but she continues to have weekly seizures. Hypomelanosis of Ito is a well-known cause of hemimegalencephaly and is often associated with intractable epilepsy and hemiparesis. Hemispherectomy can often be an effective treatment in intractable cases.