We present a case of germinal tumor of the pineal gland, treated with a ventriculo-atrial shunt, cytostatics and radiotherapy. Two and a half years later, in Spite of the clinical remission of the cerebral tumor a metastasis appeared in the abdominal cavity. After reviewing the current literature, the necessity of using millipore filters in the CSF derivation systems when dealing with malignant cerebral tumors to avoid the spreading of malignant cells through the CSF.