Histo: Upper GI Disease Flashcards
What is a key histological feature of the oesophageal mucosa?
Presence of submucosal glands
what is the Z-line?
The point in the oesophagus at which the epithelium transitions from being squamous to being columnar
What does the cell types does the body and fundus of the stomach have in abundance?
Specialised glands responsible for producing acid and enzymes
- Parietal cells - produce HCL and IF
- Chief cells - produce pepsinogen and gastric lipase
Which part of the stomach tends to be affected by H. pylori-associated gastritis?
Pylorus and antrum
What are the three layers of the gastric mucosa?
- Columnar epithelium
- Lamina propria
- Muscularis mucosa
Describe the structure of the duodenal mucosa
Intestinal type epithelium - glandular epithelium with goblet cells
Villous architecture
What is the normal villous: crypt ratio?
2:1
What does the presence of goblet cells in the stomach signify?
Intestinal metaplasia
NOTE: goblet cells are NOT normally seen in the stomach
What is the most common cause of oesophagitis
Reflux oesophagitis/GORD
What is the characteristic histological feature of acute oesophagitis?
Presence of lots of neutrophils
What can acute oesophagitis result in?
- Ulceration
- Fibrosis
- Haemorrhage
- Perforation
- Stricture
- Barrett’s oesophagus
Define Barrett’s oesophagus.
Metaplastic process by which the normal sqaumous epithelium of the lower oesophagus is replaced by columnar epithlieum
NOTE: this is also known as columnar-lined epithelium (CLO)
What are the 2 types of oesopahgeal metaplasia in Barrett’s
- Gastic metaplasia: no goblet cells
- Intestinal metaplasia: with goblet cells (associated with increased risk of cancer)
NOTE: metaplasia is reversible
Define dysplasia.
Changes showing some of the cytological and histological features of malignancy but with no invasion through the basement membrane.
What is adenocarcinoma of the oesophagus associated with and which part does it affect?
- Associated with reflux
- Affects lower 1/3 of oesophagus
- Most common type of oesophageal cancer in developed countries
Describe the main histological feature of oesophageal adenocarcinoma
Moderate to well-differentiated, mucin producing glands (intestinal type mucosa)
Usually adjacent regions of Barrett’s present
What is squamous carcinoma of the oesophagus associated with and which part does it affect?
- Smoking and alcohol
- It tends to affect the upper 2/3 of oesophagus
- It is the most common type of oesophageal cancer in developing countries
What are the main histological features of squamous cell carcinoma of the oesophagus?
Cells produce keratin (normal oesophageal squamous epithelium is non-keratinised)
Intercellular bridges
How is eosinophilis oesophagitis treated?
- Steroids
- Allergen removal
NOTE: this is associated with an allergic reaction (asthma of the oesophagus). It is due to allergy to food causing muscle spasm and dysphagia.
What is the commonest cause of oesophageal varices?
- Cirrhosis of the liver (Most common)
- Portal vein thrombosis
List some causes of acute gastritis
Chemical: NSAIDS, alcohol, corrosives
Infection: H pylori
List some causes of chronic gastritis
- Autoimmune (e.g. pernicious anaemia, anti-parietal cell) - affects body
- Bacterial (H. pylori) - affects antrum
- Chemical (NSAIDs, bile reflux) - affects antrum
NOTE: the key inflammatory cells in chronic gastritis are lymphocytes
What is mucosa-associated lymphoid tissue and what is their presence indicative of?
- Chronic gastritis caused by H. pylori infection induces lymphoid tissue in the stomach
- The presence of lymphoid follicles in a stomach biopsy, is highly suggestive of H. pylori infection
- This is important because it is associated with an increased risk of lymphoma
What are some complications of H. pylori gastritis
- Adenocarcinoma
- MALT lymphoma
H. pylori asscoaited with 8x increased risk of gastric cancer
Name a key virulence factor that enables H. pylori to cause chronic infection.
Cag-A positive H. pylori has a needle-like appendage that injects toxins into intercellular junctions allowing bacteria to attach more easily
List some other cause of gastritis.
- CMV
- Strongyloides
- Crohn’s disease
What are the two pathways that lead to the development of GI cancer?
- Metaplasia-Dysplasia pathway (e.g. oesophageal cancer)
- Adenoma-Carcinoma pathway (e.g. colon cancer)
Define gastric ulcer.
A break in the gastric mucosa. The depth of the loss of tissue goes beyond the muscularis mucosa (into the submucosa)
NOTE: if you only get loss of surface epithelium with or without involvement of the lamina propria then it is an erosion
What is the difference between acute and chronic ulceration?
Chronic ulcers are accompanied by scarring and fibrosis
What must you do with all gastric ulcers?
They should all be biopsied to rule out malignancy.
List some complications of gastric ulcers.
Bleeding - anaemia; massive haemorrhage and shock
Perforation - peritonitis
What type of cancer is gastric cancer?
- 95% adenocarcinoma
- 5% squamous cell carcinoma, lymphoma (MALToma), gastrointestinal stromal tumour (GIST), neuroendocrine tumours
What are the two main morphological subtypes of gastric adenocarcinoma? What are their key features?
- Intestinal: well-differentiated, presence of gland producing mucin
- Diffuse: poorly differentiated, composed of single cells with no attempt at gland formation
Name two types of diffuse adenocarcinoma of the stomach.
- Linitis plastica
- Signet ring cell carcinoma
What is the overall survival rate of gastric cancer?
15%
What is gastric lymphoma/MALToma? How is it treated?
- Lymphoma of the gastric mucosa that is driven by chronic inflammation (H. pylori gastritis)
- Consists of lots of B lymphocytes (marginal zone)
- Treatment: if limited to stomach and H. pylori present - H. pylori eradication
NOTE: if H. pylori is also present, crypts may also contain neutrophils
What causes duodenitis and duodenal ulcers?
- Caused by increased acid produced in the stomach that spills into the duodenum
- It can also occur due to chronic inflammation and gastic metaplasia with H. pylori infection
List some other pathogens that affect the duodenum.
- CMV
- Cryptosporidium
- Giardiasis
- Whipple’s disease (Tropheryma whippelii)
List some histological features of coeliac disease.
- Villous atrophy
- Crypt hyperplasia
- Increased intraepithelial lymphocytes (>20 per 100 enterocytes)
NOTE: the T cell response to gliadin in Coeliac disease is responsible for the damage to villi
What is lymphocytic duodenitis?
- When you get the inflammatory changes (increased intraepithelial lymphocytes) without architectural changes
- Many people with this condition either have coeliac disease or will go on to develop coeliac disease
How is coeliac disease diagnosed?
Antibodies: anti-tTG, anti-endomysial
Duodenal biopsy
NOTE: duodenal biopsy will be normal in people with coeliac disease who have been following a strict gluten-free diet
Which other condition has very similar clinical and histological features to coeliac disease?
Tropical sprue
What type of lymphoma is associated with coeliac disease
Enteropathy associated T cell lymphoma
NOTE: lymphomas in the stomach due to H. pylori are B cell lymphomas
