Arachnoid cyst as a complication of ventricular shunting.

Overdrainage of cerebrospinal fluid (CSF) is a well-known complication of shunting procedures. Several clinical manifestations of excessive drainage of CSF have been documented, such as subdural hematoma, subdural effusions, slit ventricles, isolated IV ventricle, etc. To the authors' knowledge, this is the first report of an arachnoid cyst due to the excessive function of a VP shunt.