Hirschsprung's disease is a medical problem where the enteric nervous system is missing from the end of the bowel. When the ENS is absent, the region of the bowel that is aganglionic fails to relax causing a blockage in the bowel. People with Hirschsprung disease always have aganglionosis (lack of neurons) at the end of the bowel, but the length of bowel that is aganglionic varies. Severe symptoms may occur with even short segments of aganglionosis and symptom severity does not correlate well with the extent of aganglionic bowel. The absence of ganglion cells results in a persistent over-stimulation of nerves in the affected region, resulting in contraction and thus leading to delayed passage of stool, constipation and abdominal distension. In this case we see an aganglionic part of the sigmoid colon.