Migratory schwannoma of the cauda equina with a change in radicular pattern: illustrative case.

Background: Intradural spinal tumors are an uncommon entity with a variety of pathologies and symptom patterns. Few cases reports in the literature have described tumor migration within the spinal canal.
Observations: A 38-year-old male presented with bilateral upper lumbar radicular symptoms of anterior thigh pain, with an enhancing tumor of the cauda equina initially located at L1-2. He declined surgery initially, and at a follow-up 3 years later, his symptoms were unchanged but the tumor was now located at T12-L1. He again declined surgery, but 3 months later, he had a significant change in his pain distribution, which was now along his posterolateral right leg to his foot with associated dorsiflexion and extensor hallicus longus weakness. At this time, the tumor had migrated to L2-3. He underwent laminectomy and tumor resection with resolution of his radicular symptoms and improvement in his strength back to baseline by the 1-month follow-up. Pathology was consistent with a World Health Organization grade I schwannoma.
Lessons: Migratory schwannoma is a rare entity but should be considered when radicular symptoms acutely change in the setting of a known intradural tumor. Repeat imaging should be performed to avoid wrong-level surgery. Intraoperative imaging can also be used for tumor localization.