Intramedullary abscess caused by a missed congenital dermal sinus. A 12-month-old girl presented with fever and ascending quadriparesis. She had a midline skin dimple in the upper sacral area that had been discovered in her neonatal period. Imaging studies revealed a holocord intramedullary abscess and congenital dermal sinus. Spinal MRI shows a diffuse swelling of the spinal cord and a high signal intensity up to the medulla oblongata and a low-lying conus to the S3 level. On gadolinium-enhanced image, dilatation of the central canal and multiple intramedullary rim-enhancing abscesses are observed. A dermal sinus tract (arrow) is seen from the skin dimple to a bony defect at the S3 level.