Inflammatory bowel disease
Ulcerative colitis

Topic Completed: 1 September 2014

Minor changes: 13 April 2021

Copyright: 2003-2021,, Inc.

PubMed Search: Ulcerative colitis[title]

Hanni Gulwani, M.B.B.S.
Page views in 2020: 32,645
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Cite this page: Gulwani H. Ulcerative colitis. website. Accessed April 14th, 2021.
Definition / general
  • Affects 4 - 12 per 100,000 in U.S., usually whites, peak onset ages 20 - 25 and 70 - 80 years; no gender preference
  • Almost always rectal involvement at disease onset but may develop rectal sparing and patchiness after treatment or chronic disease, resembling Crohn's colitis (Am J Clin Pathol 2004;122:94)
  • Moderate to markedly active chronic cecal involvement is associated with backwash ileitis (Am J Clin Pathol 2006;126:365, Am J Surg Pathol 2005;29:1472)
  • Ileal changes in 17%, generally mild (villous atrophy, increased inflammation, scattered crypt abscesses), not associated with increased rate of ileo-anal pouch complications, dysplasia or carcinoma; attributed to backwash etiology or other pathogenetic mechanisms (Am J Surg Pathol 2005;29:1472)
  • Extraintestinal manifestations: migratory polyarthritis, sacroiliitis, ankylosing spondylitis, pyoderma gangrenosum, clubbing of fingertips, primary sclerosing cholangitis, pericholangitis, uveitis, cholangiocarcinoma (rare)
Clinical features
  • Symptoms: relapsing, bloody mucoid diarrhea (stringy mucus) with pain / cramps relieved by defecation; lasts days / months, then remission for months / years; initial attack may cause medical emergency for fluid and electrolyte imbalance
  • Complications: perforation, toxic megacolon (due to toxic damage to muscularis propria and neural plexus with shutdown of neuromuscular function), iliac vein thrombosis, carcinoma, lymphoma
  • Skip areas: typically associated with Crohn's disease but occur in UC with long term oral or topical therapy; also associated with focal, appendiceal or only left sided disease; initial presentation in pediatric patients may show skip areas
  • UC patients with primary sclerosing cholangitis show a propensity for more extensive but less active, disease; also, rectal sparing and patchy disease activity is not seen (Am J Surg Pathol 2009;33:854)
  • Definitive diagnosis (per Sternberg): diffuse disease limited to colon, rectal involvement with continuous proximal involvement; no skip lesions; no deep fissural ulcers; no transmural sinus tracts, no transmural lymphoid aggregates or granulomas
Case reports
  • Local or systemic steroids, infliximab (monoclonal antibody to tumor necrosis factor, N Engl J Med 2005;353:2462), total colectomy; note - steroid refractory disease is CMV+ in 25%, often detectable only by immunohistochemistry (Am J Surg Pathol 2004;28:365)
  • 30% require colectomy during first 3 years due to uncontrollable disease
Gross description
  • Ulceroinflammatory disease, usually limited to colon, diffuse continuous disease from rectum proximally (pancolitis in some cases), see exceptions above; ileitis and involvement of appendix also occurs in continuity with severe colitis; anal lesions also (fissures, fistulas, skin excoriation, abscess); disease worse distally than proximally
  • Usually no deep fissuring ulceration, no strictures or fistulas, no sinus tract formation, no small intestinal involvement, no serositis, no bowel wall thickening, no fat wrapping
  • Early: mucosa is hemorrhagic, granular, friable; changes usually diffuse (similar intensity throughout)
  • Late: extensive ulceration along bowel axis but usually not serpentine as in Crohn's disease; have pseudopolyps (isolated islands of regenerating mucosa) and flat mucosa; usually normal wall thickness and normal serosa; severe cases may have megacolon or fibrotic, narrow or shortened colon
Gross images

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Inflammatory pseudopolyps

Continuous hemorrhage

Toxic megacolon

Active disease

Microscopic (histologic) description
  • Affects primarily mucosa and submucosa, except in most severe cases
  • Active changes include diffuse mononuclear inflammatory infiltrate in lamina propria, crypt abscesses (neutrophils in glandular lumen) and cryptitis but usually no neutrophils in lamina propria and reduced intraepithelial mucin; plasma cells are common at base of crypts (basal plasmacytosis), muscularis mucosa may be exposed by ulceration or be covered by granulation tissue and reepithelialization; submucosal fibrosis present; may have Schwann cell proliferation (Hum Pathol 2009;40:1159)
  • Chronic changes include architectural glandular disarray (branching and irregular glands, not parallel and not evenly spaced, irregular luminal border; also present in recently diagnosed ulcerative colitis) with reactive epithelial changes (nuclear enlargement, mitotic activity, reduced mucin), glandular atrophy (glands don’t reach muscularis mucosa), hypertrophic muscularis mucosa, mast cells at border with normal mucosa, Paneth cells, hyperplastic endocrine cells, mucosal capillary thrombi; pseudopolyps are composed of granulation tissue, inflamed and hyperemic mucosa, may have multinucleated stromal giant cells (J Clin Pathol 1993;46:874)
  • Endarteritis obliterans in submucosal arteries (10%)
  • No granulomas, no fissures, no transmural inflammation (except in fulminant cases), no submucosal edema or inflammation, no neuronal hyperplasia
  • Definitive diagnostic criteria: diffuse disease limited to colon, involvement of rectum, no transmural lymphoid aggregates or granulomas
  • Chronic ulcerative colitis in remission: architectural glandular disarray (branching and irregular glands, not parallel, not evenly spaced, irregular luminal border) with reactive epithelial changes (nuclear enlargement, mitotic activity, reduced mucin), glandular atrophy (glands don't reach muscularis mucosa, reduced number of crypts), hypertrophic muscularis mucosa, Paneth cells; these findings are not specific, must be interpreted with clinical and endoscopic findings
  • Children: initial rectal biopsies show diffuse architectural abnormalities in fewer (32%) cases, have shorter duration of symptoms (mean 17 weeks) than adults (mean 55 weeks, Am J Surg Pathol 2002;26:1441)
  • Stomas / pouches: may develop colonic metaplasia and ulcerative colitis-like lesions, including inflammatory polyps
  • The presence of 1+ tissue sections from an IBD patient's colectomy specimen showing complete absence of histologic features of chronicity or activity but bordered on both sides by chronic or chronic active disease, does not justify changing diagnosis from UC to Crohn's disease (Am J Surg Pathol 2010;34:689)
Microscopic (histologic) images

Contributed by Elaine Alt, M.D.

42 year old female with history of ulcerative colitis

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Crypt abscesses


Intense inflammation with loss of goblet cells

Multinucleated stromal giant cells (arrows)

Positive stains
Molecular / cytogenetics description
Differential diagnosis
Pediatric ulcerative colitis
Definition / general
  • More likely than adults to have patchiness of microscopic chronicity (21%), relative or absolute (23% / 3%) rectal sparing, relatively normal rectal biopsies; more likely to have initial pancolitis (42%, Am J Surg Pathol 2004;28:190)
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