An unusual sequelae of an infected persistent dermal sinus tract.

CASE REPORT: We present a case of a child born with a birthmark over the lumbar spine, which harbored a pinhole-sized opening. At 6 months of age the child presented with fever of unknown origin. Subsequent lower extremity pain resulted in imaging studies that revealed a spinal mass with extension into the posterior mediastinum. At operation, the child was found to have an infected dermal sinus tract. DISCUSSION: This case highlights the importance of a thorough examination of the midline craniospinal axis in children with fever of unknown origin. To our knowledge, this is the first reported case of an infected dermal sinus tract with extension into the posterior mediastinum.