BRIEF REPORT Management of Children With Metastatic Spinal Myxopapillary Ependymoma Using Craniospinal Irradiation Daniel M. Chinn, MD, 1 Sarah S. Donaldson, MD, 1 Gary V. Dahl, MD, 2 Jon D. Wilson, MD, 3 Stephen L. Huhn, MD, 4 and Paul G. Fisher, MD 2,5 * Key words: myxopapillary ependymoma; craniospinal irradiation; metastasis; children; filum terminale Ependymomas comprise 10–20% of all parenchymal tumors in the spinal cord among children, compared with 50–60% in adults [1–4]. Myxopapillary ependymoma (MPE) is a distinct histologic variant first described in 1932 by Kernohan [5]. It is noteworthy for pseudopap- illary architecture, arborizing vasculature, and mucin production [6] (Fig. 1). MPE usually arises in the filum terminale, and only rarely originates in the brain, the superior spinal cord, or an extradural site, such as the subcutaneous sacrococcygeal region [7–12]. This tumor is diagnosed most frequently during the fourth decade of life; children rarely harbor MPE [6,13]. The clinical course of a patient with MPE is typically indolent. Total resection can frequently be achieved by severing the fi- lum terminale from its origin and dissecting the tumor from nerve roots. Anaplastic transformation is unlikely to occur; however, this tumor has a tendency to invade lo- cally and to recur in 15–33% of patients [1,3,6,10,14– 16]. Although considered benign, MPE can sometimes ex- press a malignant phenotype. Intracranial, spinal, and systemic metastases have been reported following local treatment of spinal disease in both children and adults [3,10,13,14,17–20]. In addition, several cases of meta- static spinal ependymoma have been reported in the lit- erature, none of which were described as MPE occurring in a child [1,21,22]. Here we report three children with metastatic spinal MPE, two occurring at diagnosis and one at the time of disease progression, all managed suc- cessfully with craniospinal irradiation (CSI). CASE 1 A 13-year-old boy presented with a 13-month history of progressive lumbosacral pain. Physical examination revealed atrophy of the gluteal muscles, quadriceps, and gastrocnemius, 4/5 strength in the extensor hallucis lon- gus muscles, and hyperreflexia with ankle clonus. MRI of the brain and spine revealed an expansile, intramed- ullary mass extending from the conus medullarus to the sacrum with heterogeneous enhancement and leptomen- ingeal seeding to the midthoracic spine, as well as dis- crete nodules at the C5 and T2 levels. A T12 through L5 laminectomy was performed. Only a partial resection could be achieved because of the risk of neurologic injury. Pathology revealed MPE, with a low MIB-1 index (predominantly 1%, focally up to 3%). This monoclonal antibody reacts with the Ki-67 nuclear antigen, a marker seen in cycling cells (G1, S, G2, M phases) but not in noncycling cells (phase G0). The child received postoperative CSI to a dose of 35.7 Gy to the cranium and spine, followed by boosts to total doses of 44.2 Gy to C3 through T3 and 50.4 Gy to T12 through the sacrum. The overall treatment time was 39 days using 1.7 Gy/fraction. MRI of the spine 1 year after irradiation demonstrated stable abnormalities at C5, T2, and T12 through the conus medullaris. CASE 2 An 8-year-old girl presented with a 9-month history of left lower extremity pain radiating to the hip and buttock 1 Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 2 Department of Pediatrics, Stanford University School of Medicine, Stanford, California 3 Department of Pathology, Stanford University School of Medicine, Stanford, California 4 Department of Neurosurgery, Stanford University School of Medi- cine, Stanford, California 5 Department of Neurology, Stanford University School of Medicine, Stanford, California Grant sponsor: NIH/NINDS; Grant number: K12 NSO 1692-05. *Correspondence to: Paul Fisher, MD, Room A343, Stanford Univer- sity Medical Center, 300 Pasteur Drive, Stanford, CA 94305-5235. E-mail: pfisher@stanford.edu Received 14 February 2000; Accepted 20 April 2000 Medical and Pediatric Oncology 35:443–445 (2000) © 2000 Wiley-Liss, Inc.