pathology of the large intestine dr. shaun walsh ninewells hospital dundee
TRANSCRIPT
Pathology of the Large Intestine
Dr. Shaun Walsh
Ninewells Hospital
Dundee
• Large bowel is affected in a vast array of diseases
• Large bowel pathology varies widely worldwide
• Large bowel pathology varies with age
• We have 50 minutes!
Pathology of the Large Bowel
• Common diseases only
• Western world diseases only
• Adult diseases mostly
• Focus on the visual aspects of these diseases
Pathology of the Large BowelCore content
• Diverticular disease• Ischaemia• Antibiotic induced colitis• Microscopic Colitis• Radiation colitis
• Inflammatory bowel disease and colon cancer are separate lectures
Pathology of the Large BowelCommon diseases
• Endoscopic appearance
• Macroscopic (Gross) appearance
• Histopathologic appearances
• Discussion
• Diagnostic tests, treatments etc… will be covered elsewhere
Pathology of the Large BowelLecture plan
Pathology of the Large BowelNormal appearance
Pathology of the Large BowelPatient Endoscopy 1
Arrows denote diverticular orifices
Pathology of the Large Bowel
Pathology of the Large Bowel
Pathology of the Large Bowel
On transverse slicing
Pathology of the Large Bowel
Muscularis
Serosa
Pathology of the Large Bowel
Diagnosis?
• Common
• Often assymptomatic
• Related to low fibre diet and increased intralumenal pressure
• Symptoms only if complicated…surgery
Diverticular disease of the Large Bowel
• Complications
- Inflammation- Rupture- Abscess- Fistula- Massive bleeding
Diverticular disease of the Large Bowel
Pathology of the Large BowelPatient Endoscopy 2
Withering of crypts and smudging of lamina propria
Diagnosis?
• Elderly
• Left sided disease
• Aetiology
- CVS disease - Atherosclerosis of mesenteric vessels
- A.Fibrillation - Shock
- Embolus - Vasculitis
Ischaemia of the Large Bowel
Diagnosis: Ischaemic colitisHistopathological clues
• ‘withering of crypts’
• ‘pink smudgy lamina propria’
• ‘fewer chronic inflammatory cells’
• Clinical context:Elderly people
Left sided
Segmental on endoscopy
• Complications
- Massive bleeding
- Rupture
- Stricture
Pathology of the Large BowelIschaemic colitis
Pathology of the Large BowelPatient Endoscopy 3
Pathology of the Large Bowel
Patchy yellow membranous exudate on mucosal surface
Pathology of the Large Bowel
Explosive fibrinopurulent exudate on surface
Explosive lesions on mucosa
Diagnosis?
• Patients on broad spectrum antibiotics
• Clostridium Difficile selected out
• Toxin A and B attack endothelium and epithelium
• Massive diarrhoea and bleeding
• Treat with Flagyl/Vancomycin
• May need colectomy and may be fatal
Antibiotic-induced “Pseudomembranous” colitis
Pathology of the Large BowelPatient 4: Watery diarrhoea
Normal Mucosa
Collagenous Colitis
Collagenous Colitis
Increase in thickness of subepithelial collagen
Collagenous Colitis
• Thickened basement membrane
• Normal is between 2-3 microns
• Disease is patchy
• Associated with intraepithelial inflammatory cells
• No chronic architectural changes
• Check clinical history for watery diarrhoea, normal endoscopy, drug history etc
Pathology of the Large BowelPatient 5: Watery diarrhoea
Normal Mucosa
Normal crypt architecture
Massive increase in intraepithelial lymphocytes
Lymphocytic Colitis
• No chronic architectural changes in crypts• Intraepithelial lymphocytes are raised• No thickening of BM
• Check for correct history, normal endoscopy
• Raise possibility of Coeliac disease in report
Microscopic colitis?
• A misnomer somewhat• Normal endoscopy• Useful for cases with mixed features of
CC and LC• Should use in appropriate clinical context• Not Crohn’s or UC• Be prepared to reclassify on subsequent
biopsies
Pathology of Large BowelPatient 6
Rectal biopsy: Pt with history of cervical carcinoma
Radiation Colitis
• Chronic active or inactive colitis
• Telangectasia
• Bizarre stromal cells, bizzarre vessels
• May be other complications of immunosuppression if also on chemotherapy
• Should only be reported with certainty in the clinical context
Pathology of Large BowelPatient 7
Busy epithelium but no crypt irregularity
Florid diffuse acute cryptitis
Focal acute cryptitis in otherwise unremarkable colonic mucosa
Acute (infective) Colitis
• Infection
• Rarely Drugs, ischaemia, endoscopy prep.
• But not specific for infection as it may rarely herald the onset of IBD.
• Needs to be followed up closely.
• Diverticular disease
• Ischaemia (Ischaemic colitis)
• Antibiotic induced colitis
• Microscopic colitis
• Radiation Colitis
• Infective Colitis (acute colitis)
• Ulcerative Colitis and Crohn’s disease
Pathology of the Large BowelCommon diseases
Others
• CMV
• Mycophenylate
• Graft versus Host disease
• Etc…