Preschooler with constipation and anal stenosis on physical exam

CT and MRI of Currarino syndrome
3D CT of the pelvis (left) shows near complete absence of the lower sacrum with the sacrum having a sickel shape on the right. Midline sagittal T2 MRI of the lumbar spine (middle) shows the conus medullaris to be low in position terminating at L5. Off center sagittal T2 MRI (right) shows a small round low signal intensity lesion anterior to the S2 vertebral body.

The diagnosis was caudal regression syndrome in the form of Currarino syndrome with anal stenosis, a sickle shaped and hypoplastic sacrum, and a presacral mass in the form of an anterior myelomeningocele.