[Transient enlargement and spontaneous regression of interhemispheric cysts--a case report]

We report a 5-year-old male patient with interhemispheric cysts which showed spontaneous reduction in size. The patient was consulted to our hospital at 2 days of life for the evaluation of intracranial cysts found by fetal ultrasonography. Magnetic resonance imaging (MRI) on admission disclosed multiple cysts in the interhemispheric region and agenesis of the corpus callosum. MRI performed later disclosed the association of pachygyria and heterotopia. On follow-up MRIs, the cysts peaked in size at 5 month of age and gradually reduced thereafter. He showed transient hypertonia but had neither neurological deficits nor signs of increased intracranial pressure except transient hypertonia throughout the course. The present case is the first with interhemispheric cysts showing spontaneous reduction in size. While the present case suggested that an interhemispheric cyst dose not necessarily need a surgical treatment, and that it is difficult to determine surgical indication based on clinical manifestations.