Ependymoma of the cauda equina region: diagnosis, treatment, and outcome in 15 patients.

New diagnostic imaging techniques make possible a reappraisal of current diagnostic, therapeutic, and management strategies for certain rare lesions of the central nervous system. With this in mind, we have reviewed our experience with ependymoma of the filum terminale and cauda equina region. Fifteen patients with this tumor have been treated since 1955. Typical presentations included pain, lower extremity weakness, and, occasionally, bladder dysfunction. Delays in arriving at the proper diagnosis have been the rule; however, we have noted a substantial increase in the number of these tumors referred to us since the advent of magnetic resonance imaging. Treatment includes surgical resection to the extent consistent with preservation of neurological function; postoperative irradiation appears to be of benefit in controlling recurrence except in those patients whose well-circumscribed tumors have been removed completely. Presence of urinary difficulties at the time of diagnosis is a relatively poor prognostic sign, and a more liberal use of magnetic resonance imaging in cases of persistent or recurrent low back and radicular pain unresponsive to conservative therapy may help to achieve earlier diagnosis. Because of the possibility of late recurrence, prolonged follow-up is mandatory for all patients, and magnetic resonance imaging is the diagnostic tool of choice.