Diverticular disease, colon

During the prediverticular phase of the disease there is a marked thickening of the colon wall due to the thickening of the tenia and the circular muscular layer. An increase in the elastine content of the tenia is present. The circular muscular layer forms interdigitating processes that criss-cross the lumen and give it a corrugated appearance. The muscular thickening causes redundancy of the mucosal folds, thereby increasing the narrowing of the lumen. This pathological change has been named myochosis and it will be observed most typically in the sigmoid colon.

Findings on barium contrast enema are characterized by luminal narrowing due to the muscular thickening. There is a series of finger-like or wedge-shaped indentations along both margins of the colon. Haustral clefts are not symmetric on both sides and not facing each other anymore. On the contrary they indent alternatively from one border to another creating a staggering effect and giving the margins of the colon a serrated or "saw-toothed" or "zig-zag" pattern. Typically these changes persist during full distension because of the muscle thickening whereas those due to spasm will disappear during colon distension. Similar luminal changes will be seen on cross-sectional imaging by CT, a method which also allows appreciation of the thickened wall itself.

ALB