Cranial MR imaging in hypomelanosis of Ito.

Hypomelanosis of Ito (HI) is a rare neurocutaneous syndrome frequently associated with neurologic abnormalities. Approximately 95 cases have been reported in the literature. Intracranial findings demonstrated by magnetic resonance imaging in a patient with HI include hemimegalencephaly, abnormal white matter signal, and small discrete bilateral periventricular cysts. No gray matter heterotopias or other migrational abnormalities were identified. Periventricular cystic lesions have not been described previously in this condition.