An association of subtotal cerebellar agenesis with organoid nevus--a possible new variety of neurocutaneous syndrome.

A quite unique patient aged 13, characterized by a combination of organoid nevus on the left scalp and subtotal cerebellar agenesis accompanied by hypoplasia of the pons and midbrain, was reported. Cardinal clinical features consisted of nonprogressive cerebellar manifestations including intention tremor and ataxia, speech and visual disturbance and mental retardation. An electronystagmogram demonstrated periodic alternating nystagmus. A clinical diagnosis of cerebellar agenesis in this case was made through the demonstration of characteristic features in metrizamide CT and midline sagittal tomography of metrizamide cisternography of the posterior fossa. An extensive review of the literature revealed three papers dealing with organoid nevus associated with various neurological abnormalities, but no single case with a similar combination of cutaneous organoid nevus and cerebellar agenesis had been reported.