Ulcerative Colitis
Differential Diagnosis
- Fungal, mycobacterial, amebic and other parasitic diseases must all be ruled out by close inspection and by laboratory tests
- In cases of ulcerative colitis refractory to treatment, cytomegalovirus must be ruled out immunohistochemically (link)
- Quiescent colitis may be histologically indistinguishable from the effects of radiation or chemotherapy or chronic ischemia
- Clinical correlation is necessary
- Segmental colitis associated with sigmoid diverticular disease may be histologically identical to ulcerative colitis
- Clinical correlation is necessary
| Ulcerative Colitis |
Crohn Disease |
| Inflammation limited to mucosa and superficial submucosa |
Transmural inflammation |
| Contiguous disease, no skip lesions |
Discontinuous, patchy disease with skip lesions |
| Limited to colon |
May involve entire GI tract |
| No granulomas |
Granulomas may be present |
| Predominantly neutrophilic infiltrate with crypt abscesses |
Predominantly lympho-histiocytic infiltrate |
| Perinuclear anti-neutrophilic cytoplasmic antibody (pANCA) favors ulcerative colitis |
Anti-Saccharomyces cerevisiae antibody (ASCA) favors Crohn disease |
- The distinction may be impossible on biopsies and always requires clinical correlation
- Rare cases deviate from some of these criteria
- Up to 15% of cases may be indeterminate even after full evaluation
- pANCA and ASCA have considerable overlap and are felt by some to lack clinical utility
| Ulcerative Colitis |
Acute Self-limited Colitis |
| Basal lymphoid aggregates frequent |
Basal lymphoid aggregates absent |
| Neutrophil infiltrate in crypts with frequent crypt abscesses |
Neutrophil infiltrate predominantly in lamina propria |
| Inflammation involves all levels of mucosa |
Inflammation largely restricted to upper and mid zones of mucosa |
| Architectural changes of chronic colitis are present |
Architecture is preserved |
| Duration at least 6 months |
Short duration |
Common organisms include Salmonella, Shigella, Campylobacter, Yersinia and viruses
- Histologically indistinguishable
