| A rare neural tube defect with characteristics of cystic dilatation of the central canal of the spinal cord, herniating posteriorly through a dorsal spinal defect. The malformation can occur anywhere along the spinal cord but appears to be more frequent in the posterior cervical and the lumbosacral region. It may be an isolated anomaly or be associated with other defects, including anorectal and genitourinary anomalies, or sacral agenesis. |