Cerebellar astrocytoma with repeated episodes of fourth ventricle isolation causing peritoneal shunt tube obstruction--case report.

A 9-year-old girl underwent total removal of a cerebellar astrocytoma complicated by hydrocephalus after postoperative meningitis, requiring a ventriculoperitoneal shunt. Five months later, headache, vomiting, and gait disturbance appeared and computed tomography detected enlarged fourth ventricle. A fourth ventriculoperitoneal shunt resulted in immediate relief of all symptoms. After 2 months, obstruction of the peritoneal tube required shunt reconstruction. This recurred three times in 8 months. At the last operation, tumor cells were detected in the cerebrospinal fluid and the substance clogging the tube. This suggested that the tumor had recurred and clogging by tumor cells had caused the repeated episodes of isolated fourth ventricle. Radiation therapy prevented further shunt obstruction and achieved remission of all signs and symptoms.