Fig. 5

Histological findings of the resection specimens. A Resection specimens showed steep caliber changes in the bowel diameter on both the oral and the anal sides of the dilated bowel. B Normal ganglion cells were seen circumferentially within the submucosa and the muscularis propria in the dilated colon 5 cm from the oral edge (dotted line in A). C At 9–11 cm from the oral edge (between the solid lines in A), there was a decrease in the number of ganglion cells in the muscularis propria, corresponding to the transition zone. C Shows the area where no ganglion cells were observed