Imaging features represent midline dorsal central disc extrusion with minimal caudal migration and marked mass effect upon the conus medullaris. Disc extrusion is a type of intervertebral disc herniation and is distinguished from a disc protrusion in that it has a narrow neck and extends above or below the disc level. It is associated with a defect in the annulus fibrosus which allows herniation of nucleus pulposus beyond the confines of the disc. It also shows no evidence of interrupted connection with the original disc and this differentiates it from disc sequestration.