Giant intradural intramedullary spinal ependymoma: illustrative case.

backgroundSpinal ependymomas are the most common intramedullary spinal cord tumors in adults but rarely span multiple vertebral segments. Giant intradural intramedullary spinal ependymomas are exceedingly rare and pose diagnostic and surgical challenges due to their size and location. OBSERVATIONS: The authors report the case of a 31-year-old female who presented with progressive neck pain, lower extremity weakness, and sensory deficits. MRI revealed a large intramedullary lesion extending 11 spinal levels from C1 to T4. Gross-total en bloc resection of a 16-cm intramedullary ependymoma was achieved via C1-T4 laminectomy with posterior midline myelotomy, guided by multimodal intraoperative neuromonitoring. Pathological examination revealed a WHO grade 2 ependymoma. Postoperative MRI confirmed no residual tumor. The patient experienced transient postoperative motor deficits with gradual neurological recovery noted at follow-up. LESSONS: This case represents one of the largest reported intramedullary spinal ependymomas in the literature and demonstrates the feasibility of gross-total resection using a posterior longitudinal midline myelotomy approach. Successful management was facilitated by careful microsurgical technique and intraoperative neuromonitoring. Early recognition and timely surgical intervention are critical in optimizing outcomes in patients with spinal ependymomas; however, patients with multilevel intramedullary tumors will likely have residual neurological deficits. https://thejns.org/doi/10.3171/CASE25686.