A3- Gastrointestinal Pathology Flashcards
What is Histopathology?
Branch of medicine concerned with the study of changes within tissues associated with disease.
Typically involves using a microscope to examine tissue samples removed from a patient to provide a diagnosis to guide clinical management.
Specimen journey
• The specimen is obtained, placed in 10%
_____ _______ ______ and transported
to the lab.
Specimen journey
• The specimen is obtained, placed in 10%
neutral buffered formalin and transported
to the lab.
Formalin is a ‘fixative’
What does this mean?
links protein molecules together to make tissues rigid and prevent decay. Also ‘kills’ pathogens making the tissue biologically inert
What happens to the speciemen in the labortatory?
- The specimen is booked in
- Placed in a numbered cassette
- Processed through formalin, alcohol, xylene and paraffin wax
- Embedded in a wax block
- Sectioned and mounted on a glass slide
- Stained
What happens after a specimen is stained
a report is produced
What is metaplasia?
Reversible transformation from one type of mature adult tissue to another
What is dysplasia?
Potentially reversible process where cells acquire genetic abnormalities which may ultimately lead on to cancer.
Classified on the basis of morphology as low or high grade
Malignant tumours
What does proliferation mean?
– Independent of the initiating stimulus
Malignant tumours
What does invasion mean?
– Beyond muscularis mucosae
– Gives potential to access vessels and lymphatics
Malignant tumours
What does metastasis mean?
– Spread to organs beyond site of origin
– Blood, lymph nodes, transcoelomic
WHat are the three basic layers of the GI tract
– Mucosa – epithelium + lamina propria (superficial layer)
– Submucosa
– Muscularis propria
Oesophagus is lined with
Squamous epithelial lining
What type of surface is there in the Duodenum for absorption
villous
Duodenum has what kind of glands?
Brunner’s gland
Stomach is lined with…
– Specialised body type with _____ ____
– Non-specialised ___ ____
– Specialised body type with parietal cells
– Non-specialised antral type
Explain what you see in the red arrow compared to black arrow
black arrow shows normal basal layer (normal squamous epilethilum)
red arrow head (glandular epiethilum)
What is a classic presentation of Barrett’s Oesophagus
Middle aged to elderly white males with raised BMI and a
history of reflux disease and hiatus hernia.
Barretts is a major risk factor for?
Major risk factor for adenocarcinoma hence screening programmes exist BUT have similar mortality rates to general population, death from oesophageal adenocarcinoma is rare and those being screened may present with interval carcinomas.
Diagnosing Barrett’s?
- Gold standard diagnostic tool is endoscopy
- Normal distal squamous epithelium has been replaced by metaplastic columnar epithelium, which is clearly visible endoscopically >1cm above the GOJ
How do you report barretts
- Barrett’s oesophagus with gastric metaplasia only
- Barrett’s oesophagus with intestinal metaplasia
- No evidence of Barrett’s oesophagus
Barretts dysplasia (rare) can be classified as?
- Endoscopically visible or not
- Classified as indefinite, low grade or high grade
What grade is this barretts
high grade
What does this show
inflammatory cells between the globlet cells
What are the histological features of gastritis?
– Inflammation – acute/chronic/granulomatous
– Helicobacter
– Intestinal metaplasia
– Gland atrophy
– Dysplasia/malignancy
Types of gastritis?
• Acute/erosive - alcohol
• Drug induced – NSAID’s, iron pills
• Ischaemia
• Radiation
• Infection (other than HP)
• Autoimmune
• Helicobacter pylori
• Chemical/reflux
Complications of HP gastritis?
• Peptic ulcer disease – 15-20% lifetime risk in those with
infection.
• Gland atrophy – intestinal metaplasia – gastric
carcinoma (linked to up to 70% of cases).
• Stimulation of mucosal associated lymphoid tissue –
extranodal marginal zone lymphoma (MALToma)
What is the generic tumour type called of these cell origins.
Epithelial
Lymphoid
Mesenchymal
Melanocyte
Mesothelial
What disease is the most common cause of malabsorption in Western
populations
Coeliac disease
• Serological tests: for Coeliac disease
– tTGA – highest sensitivity
– EMA – almost absolute specificity
Coeliac Tx
Treatment/outcome
– Excellent prognosis on gluten free diet
– Ongoing symptoms with poor compliance
– Risk of developing lymphoma
