Pediatric extraosseous sacral chordoma: case report and literature review of embryonic derivation and clinical implications.

An extraosseous intradural presentation for a sacral chordoma in the pediatric age group has not been reported to date. This is a report on an 11-year-old boy who presented with an extraosseous, intradural sacral chordoma. He underwent gross-total resection and received adjuvant proton beam therapy. Neoplastic transformation of the notochord is reviewed to illustrate the developmental basis for the surgical anatomy and pathogenesis of the classic chordoma variant. Clinical and pathological features are reviewed to differentiate this chordoma presentation from classic osseous chordomas and ecchordosis physaliphora, a related benign developmental notochordal lesion. Finally, the role of developmental signaling in the pathogenesis of chordomas from postembryonic notochordal tissue is discussed.