Colitis

General:

Gross:

Microscopic: The colitides tend to have similar histologic features, though different etiologies. There are two primary categories of colitis:

Active: The presence of neutrophils in the mucosa indicates active colitis, though they may have been present for months or longer (thus it is not termed acute). Although rare solitary neutrophils are allowed in the lamina propria of "normal" colonic mucosa, collections or an abundance (~>3 per typical mucosal biopsy specimen) of them indicate activity. Neutrophils within crypt epithelium (cryptitis) or collections within a crypt lumen (crypt abscess) are always abnormal. Erosions, ulcers, or pseudomembranes also qualify.

Chronic: Although the presence of increased mononuclear inflammatory cells in the lamina propria may be considered chronic colitis, generally a diagnosis of chronic colitis should not be rendered unless there is also other evidence of epithelial injury. This may include, roughly in order of relevance: crypt shape/alignment distortion, crypt atrophy (decrease in length &/or number), surface villiform change, Paneth cell metaplasia (if distal to the hepatic flexure), basal lymphoid nodules, and basal plasmacytosis. Be wary of specimens with no muscularis mucosae, as it normally serves as an anchor to maintain regular, closely spaced crypts; its absence may give a false impression of decreased number of crypts due to increased space between them.

Stains:

• Positive:
• Negative:
• Suggested, focused panel:

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Images:

Cases: