[Hypomelanosis of Ito associated with hemimegalencephaly]

A girl aged 1 year and 2 months with hypomelanosis of Ito was reported. She suffered from intractable epileptic seizures since the second day after birth. Characteristic bizarre hypopigmented skin lesions were seen on her left shoulder and extended in a linear fashion to the flexion side of the left upper extremity. Brain MRI revealed diffuse enlargement of the left hemisphere, dilatation of the left lateral ventricle, and neuronal migration anomalies, indicating hemimegalencephaly. The types of her seizures were secondarily generalized or unilateral initially, followed by infantile spasms at 1.5 month. Around 4 months of age, frequent partial seizures appeared. Her seizures were intractable despite vigorous anticonvulsant therapy. As patients with hypomelanosis of Ito are frequently associated with neurological abnormalities, brain MRI studies were thought to be essential in detecting central nervous system anomalies, particularly in the presence of early onset intractable seizures.