Investigations of an infected anterior sacral meningocele showed partial agenesis (white arrow) in x-ray (a); a presacral soft tissue mass (double arrow) protruding through the sacral defect (curved arrow) seen in CT (b,c); L5 butterfly vertebra (L5), scimitar-shaped sacrum and scimitar sword (inset) were observed involume rendering (VR) images (d).