Features of Hirschsprung disease with a transition zone in the distal colon. 

Hirschsprung disease is an intestinal motor disorder characterized by the absence of Auerbach and Meissner plexuses of the distal GI tract. Lower GI contrast study demonstrates a rectosigmoid ratio of <1.0. However, the depicted transition zone on the contrast enema is not accurate at determining the transition between absent and present ganglion cells.

Case courtesy of Dr Che Zubaidah Bt Che Daud, Consultant Pediatric Radiologist of the Women and Children Hospital, Kuala Lumpur, Malaysia.