Hypomelanosis of Ito. Wood's light and magnetic resonance imaging as diagnostic measures.

Hypomelanosis of Ito is an uncommonly reported neurocutaneous syndrome with a peculiar pattern of swirling hypopigmentation. The skin markings in the lightly pigmented individual are not easily visualized in regular light but can be readily seen with the use of Wood's light. We describe a 7-month-old female infant with this disorder who presented with intractable convulsions. Computed tomography showed enlargement of the left cerebral hemisphere but was otherwise not definitive. Abnormalities of neuronal migration were demonstrated with magnetic resonance imaging that could not be shown by computed tomography.