Title: Intraosseous Notochord Remnant

Imaging Findings:
Figure CT images (arrows) reveal corticated, lytic intraosseous lesion containing a cleft.

Clinical:
Most commonly an incidental finding. Rarely may be associated with back pain.

Etiology:
Embryologic notochord is a major structural organizer and inducer of chondrification and segmentation of the mesenchymal elements. Normally this entity regresses during fetal life and contributes to the formation of the intervertebral disc nucleus pulposus (1, 2). Notochord remnants, as intraosseous rests, can give rise to chordomas.

References:
1. Salisbury JR. The pathology of the human notochord. J Pathol 1993;171:253-255.
2. Darby AJ, Cassar-Pullicino VN, McCall IVV, Jaffray DC. Vertebral intraosseous chordoma or giant notochordal rest? Skeletal Radiol 1999; 28:342-346.