Case report: An 11-month-old boy presented with a 3-month history of lower extremity weakness. CT and MRI of the spine revealed an enhancing epidural mass, extending from T1 through T5 and exiting through multiple foramina. The largest extraspinal extent was located at the T3 vertebral level and was accompanied by complete T3 vertebral collapse. A second lytic lesion at the L2 vertebral body without an obvious enhancing mass was also noted. Open biopsy and decompression of the spinal cord were performed, and histopathological analysis revealed a mixed inflammatory lesion with abundant S-100 and CD1a immunoreactive Langerhans cells consistent with the diagnosis of Langerhans cell histiocytosis (LCH). Discussion: The authors present a very rare pediatric case of spinal LCH causing spinal cord compression. Possible clues to early detection, consideration of differential diagnoses, and a brief literature review are presented. © Springer-Verlag 2006.