Caudal regression syndrome

An otherwise asymptomatic 9-year-old girl was referred for pediatric neurology consultation for neurogenic bladder with urinary incontinence and chronic constipation. At observation she showed distal atrophy of the lower limbs and short gluteal cleft. She had had poor follow up over the years, and this was the first imaging exam she ever had, an MRI of the lumbar and sacral spine. Further investigation revealed that the child’s mother was diabetic.

MRI of the spine was performed with sagittal T1 and sagittal STIR. The images show partial sacrococcigeal agenesis with S2 being the last fully formed vertebra and with a hypoplastic S3. There is a complete absence of coccyx. There is also an abrupt wedge-shaped terminus of the cord, which lies opposite T12 and an abnormal course of the cauda equina with separation of the anterior and posterior nerve roots, forming the “double bundle shape.” The dural sac is abnormally highly placed, ending at L5.