LAUSR

A male neonate was referred to our hospital for the treatment of myelomeningocele and hydrocephalus related to Chiari malformation type 2. After the placement of ventriculoperitoneal (VP) shunt for hydrocephalus, an intracranial cyst, which was asymptomatic at first, expanded and caused clinical symptoms due to increased intracranial pressure. The expansion of the cyst was confirmed dominantly in the right lateral ventricle where the VP shunt was inserted. Intraoperative findings through a neuroendoscope suggested that the expanded cyst was an isolated lesion. The pressure reduction in the lateral ventricle through the shunt tube, not the malfunction of the VP shunt, might have attributed to increased intracranial pressure with the expanded cyst. The authors present this rare case, speculating the cause of the expansion of the cyst.