10/14- Large Intestine, Pathology Flashcards

Question

Describe the morphology of Crohn's disease: - Location - Continous/not - Common features

Answer 1

Affects **all the GI tract** - Most common in **ileum**, **ileocecal valve**, and **cecum** * 40% limited to the small intestine * 30% involvement of small intestine and colon - Multiple, **separate, sharply delineated** areas of disease; **skip lesions** are characteristic - **Stricture** common

Answer 2

Skip lesions in Crohn's - Normal mucosa separated by inflamed mucosa

Answer 3

- **Cryptitis** and **crypt abscess** with crypt **destruction** - **Ulcer** with abrupt transition between ulcerated and adjacent normal mucosa - Distortion of architecture due to repeated crypt destruction and regeneration - **Epithelial metaplasia** - Architectural and metaplastic changes may persist even in inactive disease - **Noncaseating granuloma**: hallmark of Crohn (35% of cases) - Absence of granuloma does not rule out Crohn

Answer 4

Colon with distortion of architecture (Crohn's disease): - Crypts not equally spaced

Answer 5

Crohn's disease - Increased chronic inflammatory cells in lamina propria - Granulomas

Answer 6

Crohn's disease: - **Cryptitis**: neutrophils in the crypt epithelial cells - **Granuloma** in lamina propria: epithelioid macrophages surrounded by lymphocyte

Answer 7

Crohn's disease: - **Cryptitis**: neutrophils int he crypt epithelial cells - Increased chronic inflammatory cells in lamina propria - **Crypts abscess**: neutrophils inside the crypt

Answer 8

- Limited to colon and rectum Common extra-intestinal manifestations of ulcerative colitis overlap with those of Crohn disease - Migratory polyarthritis - Sacroiliitis - Ankylosing spondylitis - Uveitis - Skin lesions - Pericholangitis - Primary sclerosing cholangitis (2.5% to 7.5%) Prognosis depends on severity of active disease and disease duration

Answer 9

**Ulcerative colitis** - Riable edematous mucosa - Pancolitis and its response to treatment. A: only scattered fragments of mucosa are left, C-D: over time mucosa is being regenerated

Answer 10

- Always involve rectum; then proximal extension - No skip lesions - Pancolitis: disease of the entire colon - Small intestine normal, although mild mucosal inflammation of the distal ileum, backwash ileitis, may be present in severe cases of pancolitis **Grossly:** colonic mucosa red and granular or with extensive, broad-based ulcers - Abrupt transition between diseased and uninvolved colon - **Ulcers** along the long axis of colon - **Pseudopolyp**: isolated islands of regenerating mucosa - **Mucosal atrophy** in chronic disease - No mural thickening or strictures _Complications:_ - Colonic dilation and toxic megacolon: risk of perforation

Answer 11

Ulcerative colitis

Answer 12

**Similar to Crohn**: inflammatory infiltrates, crypt abscesses, architectural crypt distortion, and epithelial metaplasia - Inflammation diffuse, limited to mucosa and superficial submucosa - Severe case: extensive mucosal destruction with ulcers that extend more deeply into the submucosa - Involvement of muscularis propria: rare _Signs of healed disease:_ - Submucosal fibrosis - Mucosal atrophy - Distorted mucosal architecture to almost normal in prolonged remission No granuloma

Answer 13

**Ulcerative colitis** - Increased chronic inflammatory cells in lamina propria

Answer 14

**Ulcerative colitis** - Cryptitis: neutrophils in the crypt epithelial cells

Answer 15

Relapsing disorder: - Episodes of bloody diarrhea with stringy, mucoid material - Lower abdominal pain, and cramps - Temporarily relieved by defecation - Duration of symptoms days to months Initial attack can present as medical or surgical emergency - \> 50% patients have mild disease, all with one relapse in 10 year - 30% require colectomy in the first 3 years after presentation Colectomy cures intestinal disease, but not extra-intestinal manifestations

Answer 16

**True**- depends on duration and extent of disease - (2% after 10 years, 8.5% after 20 years, and 17.8% after 30 years of disease)

Answer 17

Early detection of malignancy: surveillance 8 years after disease initiation - Major exception: patients with primary sclerosing cholangitis; enrollment in surveillance at the time of diagnosis - Regular and extensive mucosal biopsy is expensive

Answer 18

- Acquired pseudo-diverticular outpouchings of the colonic mucosa and submucosa - Rare under 30 yo; 50% are 60+ yo in Western population - Multiple = "diverticulosis" - Dietary differences: less common in Japan - Increased intraluminal pressure due to increased peristaltic contractions, enhanced by low fiber diet -\> decrease stool bulk, especially in sigmoid colon

Answer 19

Low fiber diet - \> Chronic constipation - \> Increased intraluminal pressure (Combined with possible connective tissue disorders) - \> Muscular hypertrophy - \> Herniation of mucosa through the muscular wall

Answer 20

Diverticulosis

Answer 21

- Most common in sigmoid colon - Small, flask-like outpouchings, 0.5 to 1 cm in diameter, along the taeniae coli _Histology:_ - Thin wall of a flattened or atrophic mucosa - Compressed submucosa, - Attenuated or absent muscularis propria Obstruction -\> inflammatory change: diverticulitis and peri-diverticulitis -\> perforation -\> pericolonic abscesses, sinus tracts, and peritonitis

Answer 22

Diverticular disease

Answer 23

- Most patients asymptomatic - Often an incidental finding - 20% have intermittent cramping, continuous lower abdominal discomfort, constipation, distention, and a sensation of never being able to completely empty the rectum * Rarely regress in early stage of development * More common: number increases and become large - Symptomatic improvement with high-fiber diet - When diverticulitis occurs, it most often resolves spontaneously and rare patients need surgery

Answer 24

- Any localized projection above the surrounding colonic mucosa - Most common in colon - Most bengin - Intestinal polyps: Non-neoplastic or neoplastic * The most common neoplastic polyp: adenoma with potential to become malignant

Answer 25

- Any neoplastic mass lesion in GI tract - Carcinoid tumors, stromal tumors, lymphomas, and even metastatic carcinoma - The most common neoplastic polyps: adenomas - Benign polyps… majority of colorectal adenocarcinomas

Answer 26

- Sessile or pedunculated - Equal genders - 50% of adults in Western world by age 50 - Surveillance colonoscopy by age 50 * If family history: screen 10 years before the youngest age at which a relative was diagnosed - Less common in Asia; increasing frequency - ADENOMA = MILD DYSPLASIA

Answer 27

- 0.3 to 10 cm in diameter - Histologic hallmark: nuclear hyperchromasia, elongation and stratification - Tubular, tubulovillous, or villous based on architecture * Tubular adenoma: small, pedunculated polyps with small rounded, or tubular glands * Villous adenoma: larger and sessile with slender villi * Tubulovillous adenoma: mixture of tubular and villous - Invasion more in villous adenoma

Answer 28

Normal colonic mucosa (pedunculated tubular adenoma); the rest of crypts are darker

Answer 29

Villous adenoma

Answer 30

#1 malignancy of the GI tract Epidemiology - 15% of all cancer-related deaths (2nd to lung cancer) - Incidence peak: 60-70 yrs of age, fewer than 20% before 50 - Males \> females - Most prevalent in US, Canada, Australia, New Zealand…

Answer 31

- Genetic and epigenetic abnormalities - Two distinct genetic pathways: * APC/β-catenin pathway, associated with WNT and the classic adenoma-carcinoma sequence * Microsatellite instability pathway, associated with defects in DNA mismatch repair - Stepwise accumulation of multiple mutations - Epigenetic events, the most common one methylation-induced gene silencing, may enhance progression

Answer 32

- Tumors in **proximal** colon often polypoid, rarely cause obstruction - Carcinomas in **distal** colon: annular with "napkin-ring" constrictions and luminal obstruction - **Both**: grow into bowel wall: palpable firm mass _Right- and left-sided cancer have similar microscopic features_ - Invasion: a strong stromal desmoplastic response - Poorly differentiated tumor: few glands - Some mucin production: poor prognosis

Answer 33

Glands with necrotic material inside

Answer 34

- Endoscopic screening for adenomas - **Cecal and other right-sided colon cancers**: fatigue and weakness due to iron deficiency anemia * Iron deficiency anemia in an older man or postmenopausal woman is GI cancer until proven otherwise - **Left-sided tumors**: occult bleeding, changes in bowel habits, or cramping/discomfort left lower quadrant

Answer 35

- Poorly differentiated and mucinous tumors: poor prognosis - Two most important prognostic factors: depth of invasion and lymph node metastases - Patients with small numbers of metastases do well for years following resection of distant tumor nodules * Clinical and molecular heterogeneity of colorectal carcinomas - Metastases: regional lymph nodes, lungs and bones * The most common site of metastases: liver

10/14- Large Intestine, Pathology Flashcards

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