Purpose or Case Report: We will present imaging findings of segmental spinal dysgenesis in a series of 3 cases of this rare congenital abnormality. We will also describe the embryological basis and pertinent clinical features.

Case 1: 8-year-old female recently adopted from China with history of severe scoliosis, neurogenic bladder, and chronic kidney disease. Plain radiographs demonstrate severe destroscoliosis in thoracolumbar region with associated kyphosis. MRI reveals multiple segmentation/formation anomalies in the lumbosacral region. The coccyx was not identified, likely representing associated partial sacrococcygeal dysgenesis. The spinal cord was severely dysgenetic in the lower thoracic region (Figure 1, white outlined arrow). The superior segment of the spinal cord extends from the cervicomedullary junction to the level of T8, where it ends abruptly. No intervening cord tissue is seen between the T8 level and lumbar region. There is an enlarged spinal cord segment at the level of the sacrum in the spinal canal, separate from the superior segment (Figure 2, solid white arrow). CT with 3D reconstruction better demonstrated multiple segmentation/formation anomalies in the thoracic and lumbosacral region, including butterfly vertebrae, hemivertebrae, and block vertebrae. There were 10 ribs on the right noted with the superior 2 ribs fused.
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Conclusions: Spinal segmental dysgenesis is a congenital developmental abnormality with severe hypoplasia/absence of variable length of the spine and spinal cord. The spinal cord in the involved portion may be severely hypoplastic to totally absent. There are no associated dorsal defects of meningomyelocele at the involved levels.