Phlegmonous colitis is a very rare disorder that presents as submucosal cellulitis. It is rarer than its gastric counterpart, discussed in Chapter 4 (379). The bowel appears thickened and congested with submucosal edema and expansion. The mucosa is intact but the folds are thickened due to the submucosal edema. An intense neutrophilic infiltrate is present in the submucosa, which variably spreads into the muscularis propria. It associates with various bacterial infections, but often an organism is not identified.