Small Bowel Tumours

Benign
Lipoma
Leiomyoma
Adenoma

Malignant
Carcinoid tumours
Carcinoma
Lymphoma
Sarcoma (GI stromal tumours)


Carcinoid Tumours
Neuroendocrine cells
Secrete gastrin/5HT/somatostatin/VIP/Insulin/other endocrine things

Site
Malignancy depends on site of origin
Appendix/Rectum
Locally invasive
Resectable
SmI/St/Col
Highly invasive
Metastatic

NB - also occur in lungs

Symptoms and Cx - Carcinoid Syndrome
Flushing
Diarrhoea
Wheezing
Abdo fibrosis
Cardiac valve fibrosis/stenosis/regurgitation

If metastasises to liver:
5HT bypasses portal system = CS
 - otherwise metab in first past metabolism
NB therefore lung tumours drain directly into system = CS


Gastrointestinal Stromal Tumours
*Stomach/SmI
SmM/neural differentiation
Ben/Malig
Malignant = higher mitotic rate/necrosis/neural differentiation


Gastrointestinal Tract Lymphomas
*GIT extranodal lymphoma

1) MALT lymphoma
2) Enteropathy-associated lymphomas
3) Other B Cell lymphomas (mantle cell Lys & follicular Lys)

1) MALT
B Cell neoplasm
Fr mucosa associated lymphoid tissue
*SmI & Col - Tx difficult
St with H.Py
H.Py = chronic inflammation = chronic inflammatory cell infiltrate
Tx of H.Py can Tx Lymphoma (therefore ABs)

2) Enteropathy-associated Lymphomas
eg a/w/ Coeliac disease
* T cell

Ulcerative Colitis

Pancolitis

Starts at rectum

Retrograde into colon

Continuous

x Skip lesions

10% Backwash ileitis (mild mucosal inflamm of distal ileum)

Epidemiology
*White
*20-25

Symptoms
Worse Pn than Crohn's
Acute appendicitis
Diarrhoea - Haem/Mel/Mucus
Toxic megacolon (toxin damage of Nplexus and MPp = shutdown of neuromuscular function = distension & gangerene. W/o intervention = perforation & sepsis)

Pathology
Limited to mucosa
Pseudopolyps (extensive superficial ulceration = small islands of residual mucosa resembling polyps)
x transmural
x serosal inflammation
x fat wrapping
x fissuring
x fistulae
x thickening

Micro
Diffuse mucosal ulceration
Cryptitis (lim to muc)
Crypt abscesses (lim to muc)
Crypt distortion (long-standing inflammation)
x Granulomas

Cx
Increased risk - dysplasia & colonic carcinoma
Up risk with time
10yrs = x20R
35yrs = 30%

Prevention
10yrly colonoscopies (NB if init BP -ve  or dysp = lower risk of Ca)

Crohn's Disease

Epidemiology
*White
*20-30yrs (any age)

RFx
SMOKING!!!

Symptoms
Insid O/S
Abdo pain
Diarr
WL
Perianal disease
Skin tags
Fisulae
Fissures
Abscesses
Appendicitis

Pathology
Sharply delimited & transmural
Mucosal damage & inflammation
Non-caeseating granulomas
Deep fissuring (rose thorn ulcers)
Cobblestoning (islands of residual mucosa surrounded by deep ulcers)
Fat wrapping of mesentery (serosal - the external surface of bowel - inflammation)
Adhesions to another bowel loop/bladder/uterus

Fistulas (fissuring ulcers extend between serosa & bowel loop/bladder/uterus) =
Pneumouria/faecesuria/air or faeces per vagina

Transmural inflamm of muscPp (main muscle coat of bowel) =
Neuromusc Hplasia & thickening of bowel wall =
Stricture =
Sx Tx

Ix
Micro
Full thickness ulceration w/ granuloma formation (50% biopsies)
Lp inflammation & cryptitis (containing Nps)
Crypt abscesses (Nps destroying crypts)

Cx
Increases ColCa x5/6

Ischaemic Bowel Disease

Any part of bowel

Causes

• Atheroma
• Emboli
• Thrombosis
• Vasculitis
• Radiation

Diverticular Disease

Diverticulosis
Outpouchings of mucosa through bowel wall
Diverticulitis
Inflamed diverticula
Diverticular Disease
Symptomatic diverticulosis
Solitary & multiple diverticula poss throughout colon/smI
*sigmoid colon

Epidemiology
Affects Western, elderly population
>60% >80
Rare in Asia & Africa

Pathology
60% only in sigmoid
Never rectum
SmI diverticula
*duodenum
Incidental
Rarely Sy

NB
Diverticulosis - if Right-sided colon = ?different disease (*younger; oriental)

Pathogenesis
Fibre diet has inverse relationship with disease
Fibre = large 'residue' in bowel
Muscularis propria thickened (raised intraluminal pressure with empty colon)

Cx
Diverticulitis (leads to perforation/Abscesses)
Fistulae (*colovesical; ut/vaginal/abdo wall)
Intestinal obstruction fr inflammatory mass
Haemorrhage - diverticula *form where arteries enter muscPp

Inflammatory Bowel Disease

Chronic relapsing inflammation of the GIT with unknown origins

2 Types

• Crohn's
• UC

Crohn's

Granulomatous disease

Can affect any part of GI tract

*smI & colon

Ulcerative Colitis

Nongranulomatous disease

Limited to colon

Both have extra intestinal inflammatory sites

Eyes
(uveitis/episcleritis/conjunctivitis)
Joints
(Monoarticular arthritis/Ank Spond/Sacroileitis)
Skin
(Erythema nodosum/vasculitis/pyoderma gangrenosum)
Liver
(fatty change/sclerosing cholangitis/hepatitis/cirrhosis)
Calculi
(higher incidence of calculi - urinary tract & GB)

Aetiology
?cause
Suggested mechanisms:
1) Inflammatory reactions
Mycobacterium
Measles
Viruses
2) Autoimmune
3) Multifocal infarction of GIT

Comparison of the Crohn's and UC

Crohn's

Mouth 2 anus

Skip lesions

Thickened bowel wall

Transmural inflammation

Granulomas

Deep fissuring ulcers

Fistula form

Cancer rare
Non-surveillance

Ulcerative Colitis

Colon only

Continuous lesion

Normal BW thickness

Mucosal inflammation

x Granulomas

Pseudopolyps

x Fistula formation

Cancer common
Surveillance

Tropical Sprue & Whipple's Disease

Tropical Sprue
Coeliac-like disease
Tropics

Aetiology
?Spec cause
Poss bacterial overgrowth (eg Ecolab/Haemophilic)
Small intestine (entire)

Presentation/CFx
*folate/B12 deficiency - pernicious anaemia

Ix
Micro
Variable

Tx
B-Sp ABs

Cx
x a/w/ T Cell lymphoma


Whipple's Disease
Rare
Systemic
*Intestine/CNS/Joints

Epidemiology
*White
M:F=10:1
*30-40yrs


Aetiology
G+ve Actinomycete - Tropheryma whippelii

Ix
Biopsy/Micro
PAS +ve macrophages within LProp =
SmI distension
E- Micro
Macrophages contain rod shaped bacilli

Coeliac Disease

Pathology affects mucosa of small intestine
Impaired nutrient absorption
Improves on withdrawal of wheat gliadins & related grain proteins from diet

3 Features

1. Small Intestine
2. Malabsorption
3. Iimproves with removal of wheat gliadins from diet.

Aetiology
*Caucasian (Irish = 1/100)
Genetic: HLA DQw2 locus
Imm-med I inj with malab

Ix
Serum
Antiendomysial antibodies
Antigliadins
Biopsy
Confirm positive aBs
Macro
Mucosa smooth
Changes prominent in proximal > distal sm I
Micro
Flattening of villi (villous atrophy)
Lengthening of crypts
Resembles colonic mucosa
Intraepithelial lymphocytosis (*cytotox T cells & up nos. of T helper cells within Lprop)

Tx
Remove wheat gliadins & related grain proteins from diet
Confirm Dx
 - 2nd biopsy post diet (n villous architecture)/gluten challenge
 - decrease in symptoms to confirm

Cx
Up risk - T cell lymphoma
Malignancies of GI Tract & Breast

Malabsorption

Malabsorption

Suboptimal absorption

Fats

Vitamins

Proteins

Carbohydrates

Electrolytes

Minerals

Water

Symptoms

Abdo pain

Bloating
Flatus
Diarrhoea
Steatorrhea
WL
Failure to thrive
Vitamin & metal deficiencies

Pathology
1) xIntraluminal digestion (digestion enzyme dysfunction)
2) xTerminal digestion (luminal brush border dysf)
3) xTransepithelial transport (epith transp dysf)

Causes
Coeliac D (coeliac sprue)
Tropical sprue
Lactose intolerance
Pancreatic insufficiency (CF/ChrPi in alcoholics)
Whipple's disease
Parasitic infection (eg G lam)
Sx (short gut syndrome, gastrectomy)
Crohn's disease

Infectious Enterocolitis

Inflammation of small/large bowel
Bact/Para/Prot/Viral

Bacterial

Pathology

1) Ingestion of toxin (Staph aureus, Clostridium perfringens)

2) Enterotoxic organisms - ingestion of organism and toxin secreted within lumen = mucosal damage (Vibrio cholera, E coli, Cl difficile)
3) Enteroinvasive organisms - ingestion of organism, which invades and damages mucosa (Salmonella, Shigella, some E coli)

 - Clostridium Difficile
Normal commensal of gut

1) Common - Antibiotic-associated colitis

Broad-spectrum ABs =
Overgrowth =
ClDiff acts as a pathogen

2) Rarer - w/o ABs
Post-surgery/Chronic illness

Ix
Macro
< inflammatory exudate

 Adheres to surface mucosa

= Pseudomembrane

Micro

< inflammation of mucosa
Neutrophils erupting from crypts - 'volcano appearance'

Parasitic & Protozoal Enterocolitis

 - Round worms
Strongyloides
Ascaris
Hookworms

 - Flatworms

Tapeworms

Flukes

 - Protozoa (seen on H&E)

Entamoeba Histolytica

Giardia lamblia

 - Entamoeba Histolytica

Faecal/Oral
Amoebas burrow into crypts
Colonic mucosa through muscularis mucosa =
Acute Dysentry

Macro

Numerous ulcers in colonic mucosa
Micro
Penetration of muscularis mucosa
Spreading out
Narrow neck
Broad base
Flask-shaped ulcers
Approx 4% of patients, parasites penetrate portal vessels
Spread haematogenously to liver
= Hepatic abscesses

*Solitary

 Up to 10cm diameter

Other abscess sites:

Lungs

Heart

Renal

Brain

Remain long after dysentry gone
Hard to Tx

 - Giardia Lamblia
Spreads via water
Attaches to small intestine mucosa
x Invasion

Pathology
Normal to blunting villi
Mixed inflamm infiltrate of Lpropria
= Malabsorptive diarrhoea


Viral Enterocolitis

Young Pts
Rotavirus

Adults
Norwalk virus (winter vomiting virus)

Immunocompromised
CMV
Acquired Immunodeficiency Virus
 - 30-60% HIV Pts = diarrhoeal illness
 - Exclusion of other pathogens
 - ?unk path/HIV