Peritoneal metastases in two patients with pineoblastoma and ventriculo-peritoneal shunts.

We report the uncommon occurrence of ventriculo-peritoneal shunt-associated peritoneal metastases in two patients with pineoblastoma. In one patient, the peritoneal cavity was the only site of recurrence; there was no evidence of disease recurrence in the central nervous system. One other patient with recurrent intracranial disease had synchronous, but asymptomatic, peritoneal metastases which were detected on an elective ultrasound. Although rare, peritoneal metastases appear to respond well to systemic chemotherapy. Ultrasound surveillance of the abdomen should be considered as a part of the routine follow-up evaluation in patients with embryonal central nervous system tumors and ventriculo-peritoneal shunts.