Gastroenterology: Pathology - Inflammatory bowel disease, diverticulosis and colorectal carcinoma Flashcards
What is ulcerative colitis?
Severe ulcerating inflammatory disease limited to colon and rectum, extending only into mucosa and submucosa
What is Crohn disease?
Inflammatory disease which may involve any part of gastrointestinal tract, typically transmural
What is the sex predilection of inflammatory bowel disease?
More common in women
At what age does inflammatory bowel disease typically present?
Teens and early 20s
Describe five morphological features of Crohn disease
- Transmural inflammation
- Skip lesions
- Non-caseating granulomas
- Fissure and fistula formation
- Punched out aphthous and linear ulcers
Name a risk factor for development of Crohn disease
Smoking
Eight extra-intestinal manifestations of inflammatory bowel disease
- Uveitis
- Migratory polyarthritis
- Sacroiliitis
- Ankylosing spondylitis
- Erythema nodosum
- Clubbing
- Pericholangitis
- Primary sclerosing cholangitis
Are the extra-intestinal manifestations of inflammatory bowel disease more common in Crohn disease or ulcerative colitis?
Ulcerative colitis
Describe three morphological features of Crohn disease
- Pseudopolyps (isolated islands of bulging regenerating mucosa)
- Continuous lesion (primarily from rectum)
- Inflammation limited to mucosa
Two possible complications of ulcerative colitis
- Toxic megacolon
- Perforation
Compare and contrast the macroscopic features of Crohn disease and ulcerative colitis, in terms of:
- Affected bowel region
- Distribution
- Tendency to stricture
- Wall appearance
Crohn disease:
- Ileum +/- colon affected
- Skip lesions present
- Stricturing
- Thickened wall appearance
Ulcerative colitis:
- Only colon affected
- Diffuse
- Rarely strictures
- Thin wall appearance
Compare and contrast the microscopic features of Crohn disease and ulcerative colitis, in terms of:
- Inflammation type
- Presence of pseudopolyps
- Ulceration
- Lymphoid reaction
- Presence of fibrosis and serositis
- Presence of granulomas
- Fistulae/sinuses
Crohn disease:
- Transmural inflammation
- Moderate burden of pseudopolyps
- Deep, knife-like ulcers
- Marked lymphoid reaction
- Marked fibrosis and serositis
- Granulomas in 35%
- Formation of fistulae/sinuses
Ulcerative colitis:
- Inflammation limited to mucosa
- Marked burden of pseudopolyps
- Superficial, broad-based ulcers
- Moderate lymphoid reaction
- Mild to none fibrosis and serositis
- No granulomas
- No fistulae/sinuses
Compare and contrast the clinical features of Crohn disease and ulcerative colitis, in terms of:
- Presence of perianal fistulas
- Fat/vitamin malabsorption
- Malignant potential
- Recurrence after surgery
- Risk of toxic megacolon
Crohn disease:
- Perianal fistulas in chronic disease
- Causes fat/vitamin malabsorption
- Malignant potential with colonic involvement
- Recurrence after surgery common
- Does not cause toxic megacolon
Ulcerative colitis:
- No perianal fistulae
- No fat/vitamin malabsorption
- Malignant potential
- No recurrence after surgery
- Can cause toxic megacolon
Five complications of diverticulosis
- Diverticulitis (infection; due to luminal obstruction of diverticulae)
- Abscess
- Sinus tracts / fistulae
- Perforation
- Haemorrhage
What is the most common GIT malignancy?
Colorectal adenocarcinoma
Describe the two main pathogenic pathways of colorectal cancer. Which is more common?
- APC/B-catenin pathway: classic adenoma-carcinoma sequence (80%), involves KRAS and p53
- DNA mismatch repair deficiency: due to microsatellite instability
Describe the typical morphology of colorectal adenocarcinomas in the proximal vs distal colon
Proximal colon: polypoid exophytic lesions, rarely cause obstruction
Distal colon: “napkin ring” constrictions with luminal narrowing, may cause obstruction
Describe the typical clinical presentation of R- vs L-sided colorectal adenocarcinomas
Right-sided: fatigue and weakness due to iron deficiency anaemia
Left-sided: occult bleeding, change in bowel habit, cramping LLQ pain
What are the two most prognostic factors associated with colorectal cancer?
- Depth of invasion
- Presence of absence of lymph node metastases
What is the most common site for colonic metastases?
Liver (rectal do not tend to metastasise to liver as unlike the colon they don’t drain via portal circulation)
Four common sites of metastasis of colorectal cancer
- Regional lymph nodes
- Liver
- Lung
- Bone
Describe the normal tissue of the anal canal
Upper 1/3: glandular columnar rectal epithelium
Middle 1/3: transitional epithelium
Lower 1/3: stratified squamous epithelium
What is squamous cell carcinoma of the anal canal associated with?
HPV
