Extraneural metastatic medulloblastoma during childhood.

From 1960 to 1977, 59 patients with histologically confirmed medulloblastoma were initially treated at Childrens Hospital of Los Angeles. Of this group, 49 have died and, of these, 34 were autopsied. Among the autopsied cases, 2 infants had neck masses that proved to be medulloblastoma that had spread from the cerebellar vermis before any surgical intervention. Four additional patients who had undergone a posterior fossa craniectomy without either the pre- or postoperative placement of a cerebrospinal fluid-diverting shunt were found to have extraneural metastatic medulloblastoma at autopsy. The extraneural metastatic medulloblastoma rate in the autopsied cases was 17.6% (6 of 34). Our series shows that the incidence of the extraneural spread of medulloblastoma is associated with being young, being male, and having diffuse tumor involvement of the subarachnoid space.