Abdominal metastases of pediatric brain tumors via ventriculo-peritoneal shunts.

Internal drainage of cerebrospinal fluid (CSF) to the abdominal cavity via a ventriculo-peritoneal shunt (VPS) is a procedure that is commonly used for the treatment of obstructive hydrocephalus. As this condition is often caused by brain tumors blocking the natural CSF pathways, a VPS, as an artificial anastomosis, can provide the means for tumor cells to be spread with the CSF. A review of the literature reveals 35 VPS-related abdominal metastases from pediatric brain tumors; 17 in patients aged 0-9 (group A) and 18 in patients aged 10-18 years (group B); the mean age of male patients was 10.5, and that of female patients, 7 years. The male-to-female ratio was 1.9 (group A 1.1, group B 3.5), and the mean interval between shunt operation and diagnosis of metastases, 16.7 months (group A 11.6, group B 22.6 months; boys 21.6, girls 7.5 months). During the observation period, 22/30=73.3% of the patients died (group A 13/15=86.7%, group B 9/15=60%; boys 13/21=61.9%, girls 9/9=100%); their mean survival time after shunting was 18.7 months (group A 15.7, group B 23.1 months; boys 25.5, girls 9 months). The four most common sources of metastases were germinomas (9 cases=25.7%; group A none, group B 9), medulloblastomas (8 cases=22.9%, group A 7, group B 1), endodermal sinus tumors (5 cases=14.3%, group A 1, group B 4), and astrocytomas (4 cases=11.4%, group A 4, group B none). Metastases via VPS are rare, but should be considered as a possible complication and mode of systemic spread in children with primary intracranial malignancy. They have a more favorable prognosis in boys and in the second decade of life.