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 |
Eosinophilic (Allergic) Proctocolitis | Ulcerative Colitis |
May occur <12 months of age | Very rare <12 months |
Marked tissue eosinophilia >60/10 HPF | May have moderate numbers of eosinophils |
Incidental Chronic Colitis | Ulcerative Colitis |
Virtually restricted to cecum/right colon | Involves rectum with contiguous disease proximally in most cases |
Incidental, asymptomatic | Nearly always symptomatic |
- Histologically indistinguishable