Heterotopic spinal cord? A curiosity.

Unusual morphological findings were encountered in a high cervical meningomyelocele sac of a neonate. Magnetic resonance imaging revealed a massive liquid-filled sac traversed by a linear structure. The spinal cord was seen to be located normally within the spinal canal. At operation, a spinal cord-like structure was identified within the sac. This cord terminated posteriorly at the neural tissue lining the meningomyelocele sac. There were fibrous strands connecting the cord to the sac like the rigging of a ship. The anterior end of this cord terminated in a fibrous band. It extended upwards into the spinal canal through the narrow neck of the meningomyelocele sac above the arch of the atlas. The whole of this cord, along with the meningomyelocele sac, was excised. Histological analysis confirmed that this spinal cord-like structure consisted of glial tissue with an ependymal-lined cavity. The excised sac was lined by neural tissue.