Spinal metastases of intracranial ependymomas. Four case reports and review of the literature.

Intracranial ependymomas tend to spread along on the liquor pathways and thus to seed subarachnoid metastatic implants. According to autopsy data, spinal seeding can be expected in 25% of cases subsequent to surgery of the primary tumor. Analysis of four of our own cases (out of 125 primary intracranial ependymomas) together with those described in the literature suggests clinical evidence of seeding in 75% of patients. 47 of 75 metastases originated from malignant infratentorial ependymomas. Malignant ependymomas metastasize earlier than benign ones. They are characterized by disseminated seeding of tumor implants along the entire spinal subarachnoid space. The median survival time after diagnosis of seeding was 6 months. 80% of all patients died within the first 12 months following diagnosis. The necessity of prophylactic spinal radiation therapy in the course of the initial treatment of intracranial ependymomas has not yet been proven.