Ulcerative Colitis (UC)

General: UC is one of the inflammatory bowel diseases, along with Crohns disease. Although historically considered to be confined to the large intestine, there is a growing body of publications indicating there may also be diffuse microscopic gastritis, without granulomas, consisting of mononuclear cells with similar immunophenotype to those found in the rectal mucosa of those affected by UC.

Classically, UC consists of inflammation & ulceration beginning in the rectum and progressing proximally in a continuous fashion, with associated fever, diarrhea, abdominal pain, & weight loss. There should be no "skip lesions" (better termed "skip areas"), or areas of essentially normal mucosa separating areas of inflammation, as can be seen in Crohn's. Colectomy may be required in the setting of impending fulminant colitis/toxic megacolon, etc.

Gross: Rectal erythema or frank ulceration, diffusely progressing proximally as far as the ileocecal valve, but not beyond. No "creeping" serosal fat and no thickened bowel wall, which suggest Crohn's instead. Fistulas usually suggest Crohn's, except in the case of fulminant colitis.

Microscopic: There is superficial colitis, confined to the upper submucosa and above, diffuse throughout an affected region. If disease has progressed to fulminant colitis, however, transmural inflammation, fistulas, and fissuring ulcers may develop due to the ischemic component. There are no granulomas (their presence points to Crohn's disease).

Stains:

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

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