Extraneural metastases of central nervous system tumors.

In the past, extraneural metastasis of central nervous system tumors was considered to be a rare event. However, more recently, a considerable body of literature has accumulated so that to date some 282 patients with extraneural metastases have been reported. Of these reported cases, 40.4% have occurred in children. Although central nervous system tumors can spread spontaneously beyond the confines of the central nervous system, most instances of extraneural metastasis occur after craniotomy or diversionary cerebrospinal fluid shunting. Extraneural metastases are universally fatal. Although it is not curative, chemotherapeutic treatment of metastases may greatly decrease the patient's discomfort and improve the quality and duration of survival. Every effort should be made to prevent this complication by avoiding diversionary cerebrospinal fluid shunting procedures or by incorporating a filtering device if a shunt becomes necessary.