Recurrent pediatric posterior fossa anaplastic ependymoma managed with multiple resections: illustrative case.

backgroundMaximal safe resection of ependymoma should be attempted whenever feasible. To clarify the potential and limits of surgery in recurrent pediatric ependymoma, the authors report a posterior fossa anaplastic ependymoma in a boy who ultimately underwent 18 resections. OBSERVATIONS: After initial multimodal therapy, resection with no detectable contrast-enhancing tumor on imaging and/or no visually apparent residual tumor intraoperatively was achieved at each operation from the 5th through the 16th, yielding 8 years 8 months of surgery-only local control. At the 17th surgery, a small remnant invading the right dorsolateral medulla was unavoidable; 7 months later, an 18th procedure achieved only partial resection and was followed by reirradiation. Recurrences arose from varying ependymal sites along the floor of the fourth ventricle rather than a single fixed locus, and a normal-appearing ependymal lining re-formed after sequential resections. Across all 18 operations, no infectious complications occurred. The tumor later progressed to circumferential brainstem involvement, and the patient died of respiratory failure 16 years 8 months after initial therapy. LESSONS: Repeated resections achieving no radiographic and intraoperative residual tumor may contribute to long-term survival in ependymoma; however, durable survival appears to depend on the persistence of locally resectable relapse. https://thejns.org/doi/10.3171/CASE25834.