Intramedullary subependymoma of the spinal cord.

A consecutive series of six patients underwent operative resection of intramedullary spinal cord subependymomas between January 1981 and August 1993. Three men and three women between the ages of 26 and 66 years experienced symptoms for a mean of 50 months preceding diagnosis. The locations of the tumors were predominantly cervical or cervicothoracic, except in one patient. At operation, a complete extirpation was achieved in each patient. No patient received further adjunct therapy. There has been no tumor recurrence in any patient after a mean follow-up period of 39 months. Most of the intramedullary spinal cord tumors are either ependymomas or astrocytomas. Clinical histories, physical examinations, and radiographic investigations are not conclusive for absolute diagnosis of subependymomas; however, intraoperative gross observations have shown these well-demarcated tumors to be located eccentrically within the spinal cord. Pathological examinations demonstrate tumors with sparse cellularity, clustering of cells, and dense fibrillary stroma. Proliferation studies with the mouse monoclonal antibody MIB-1 reconfirm the slow growth potential of these benign tumors.