Hypomelanosis of Ito with Sturge-Weber syndrome-like leptomeningeal angiomatosis.

The term hypomelanosis of Ito (HI) is applied to individuals with skin hypopigmentation following the lines of Blaschko (type 1a of patterns indicative of somatic mosaicism as defined by Happle). Even though originally described as a purely cutaneous disease, subsequent reports of HI have included a 30-94% association with multiple extracutaneous manifestations. The frequency of extracutaneous associations has led many authors to consider HI to be neurocutaneous disorder. We report a male infant with cutaneous hypomelanosis along the lines of Blaschko distributed on the left half of the body who developed status epilepticus. Neuroimaging studies disclosed an angiomatous enlargement of the right choroid plexus and a gyral pattern of cortical and subcortical calcification in the right occipital region. Thus a diagnosis could be made of HI and associated Sturge-Weber syndrome-like leptomeningeal angiomatosis. This previously unreported association lends further support to the consideration of hypomelanosis of Ito as a marker of somatic mosaicism with frequently associated neurologic abnormalities. A relationship between HI and Sturge-Weber syndrome, two neuroectodermal disorders with a genetic mosaicism basis, might be possible due to nonallelic twin-spotting which in the embryologic period would define an abnormal development of neural, vascular, and cutaneous structures.