Multifocal intradural extramedullary ependymoma, amplified: illustrative case.

Background: Ependymomas are the most frequent tumors of the adult spinal cord, representing 1.9% of all central nervous system tumors and 60% of spinal cord tumors. Spinal ependymomas are usually solitary, intramedullary lesions. While intradural extramedullary (IDEM) ependymomas are infrequent, multifocal IDEM ependymomas are exceptionally rare.

Observations: The authors reported the first case in the literature of a patient diagnosed with multifocal IDEM ependymomas who was treated with tumor resection and brain and spinal radiotherapy. The patient presented with a 10-day history of bilateral leg numbness extending to the umbilicus and gait instability. Magnetic resonance imaging (MRI) studies revealed multiple enhancing nodular nodules throughout the entire spinal canal. Brain MRI revealed no abnormal lesions. A World Health Organization grade II ependymoma was confirmed histologically. At 31 months postoperatively, the patient remained clinically asymptomatic. Although cervical and thoracic MRI revealed stable intradural nodules and several areas of leptomeningeal enhancement, no malignant cells were seen in the cerebrospinal fluid (CSF). He underwent genetic testing to determine the appropriate chemotherapeutic agent if activation of the tumor should arise.

Lessons: Because complete resection of multifocal IDEM ependymomas is not feasible, continued monitoring with brain and spine MRI is warranted to detect potential tumor dissemination in the CSF.