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SMALL INTESTINE (normal)

Simple columnar epithelium

Scattered GOBLET CELLS

Distinguish from large intestine by presence of both crypts and VILLI

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LARGE INTESTINE (normal)

long, cigar-shaped/test tube shaped goblet cells

Only crypts (no villi) this is how to distinguish from small intestine

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This is Crohns disease

1) Histo findings: blunting of the villi/abnormal villous architecture; inflammatory

infiltrate (lymphocytes & plasma) which may be transmural & deep into tissues(compare to ulcerative colitis, in which inflammatory infiltrate is often shallow, w/

mucosal involvement only)

2) skip lesions (patchy areas of inflammation, may appear ulcerated)

3) NOD2 (CARD15) , ATG16L1, IRGM (many more have been discovered, but these were

the ones emphasized in lecture)

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Creeping fat

The serosal surface is normally smooth; in Crohns you see fat globules hanging off

serosal surfaceDevelops because mesenteric fat is beginning to spread over the serosal surface

secondary to the inflammation

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In additoin to the strictures, there is transmural thickening and cobblestoning

Transmural thickening + fibrosis

stricture formation

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Absence of normal villous architecture

Inflammatory infiltrate throughout (versus only at the surface for ulcerative colitis)

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loss of villi

Arrow knife-like ulceration

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Non-caseating granuloma seen in quadrant II (light oval-shaped area near the X of the

gridlines)

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Left is UC

Entire mucosal surface is inflamed (not patchy inflammation as in Crohns)

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1) Ulcerative colitis

2) Continuous (moving front lesions; not skip lesions); broad-based ulcers and

pseudopolyps3) limited to mucosa and submucosa

4) Pseudopolyp = random areas of leftover normalmucosa in a sea of irregular

pathology (denuded epithelium

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1) There is a moving front of ulceration in this specimen, starting in the rectum and

moving proximally A) moving front of ulceration starting in rectum B) Hemorrhage C)

Cecum unaffected2) This is the common pattern in ulcerative colitis (continuous spread starting in

rectum, moving proximally)

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1) Inflammation in the mucosa only. There is also loss of architecture of mucosa

(random orientation, loss of test tubes in a rack appearance of the surface, ie loss

of cigar-shaped/fusiform glands)2) This is suggestive of ulcerative colitis

Normal findings: http://www.youtube.com/watch?v=7zrgHuplA18

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Crypt abscesses with neutrophils in the lumen = sign of active inflammation (active

chronic colitis)