Spinal myxopapillary ependymoma arising directly from a lumbar nerve root: illustrative case.

BACKGROUND: Myxopapillary ependymoma (MPE) is a rare primary neoplasm found in the brain and spinal cord that develops from ependymal cells. This tumor type has a prevalence of around 1 in 1 million persons, constitutes 1%-5% of all spinal tumors, and typically arises from the conus medullaris or cauda equina. Prognosis is generally favorable if treated appropriately with resection and, in the event of subtotal resection, radiation therapy. However, MPEs carry a risk of growing or spreading along the neural axis, so timely diagnosis and treatment are crucial. OBSERVATIONS: The authors present a unique presentation of an MPE arising directly from a nerve root at the L1-2 level. Radiographic imaging displayed an intradural extramedullary (IDEM) mass with resultant cord compression; corresponding neurological deficits prompted resection, and gross-total resection was achieved. A subsequent review of the literature identified diagnostic criteria, usual presenting features, and treatment strategies. LESSONS: MPE can be a treatable pathology, with most patients having a favorable prognosis. This tumor type should remain in the differential diagnosis when encountering IDEM lesions superior to the conus medullaris or along spinal roots. Early identification and surgical treatment with maximal resection are crucial to prevent tumor spread. https://thejns.org/doi/10.3171/CASE26297.