GI Pathology Flashcards
How long should a normal oesophagus be?
25 cm long muscular tube mostly lined by squamous epithelium
What are the two oesophageal sphincters?
Sphincter at upper end (cricopharyngeal) and lower end (gastro-oesophageal junction)
What is distinct about the distal 1.5-2cm of the oesophagus?
Distal 1.5-2 cm are situated below the diaphragm and lined by glandular (columnar) mucosa.
Where is the squamo-columnar junction?
The squamo-columnar junction is usually located at 40 cm from the incisor teeth.
What are the causes of oesophageal inflammation?
Infectious Bacterial, viral (HSV1, CMV), fungal (candida) Chemical Ingestion of corrosive substances Reflux of gastric contents
What is the reflux of bile called?
duodeno-gastric reflux
What are the risk factors for reflux oesophagitis?
Defective lower oesophageal sphincter
Hiatus hernia
Increased intra-abdominal pressure
Increased gastric fluid volume due to gastric outflow stenosis
What is a hiatus hernia?
Abnormal bulging of a portion of the stomach through the diaphragm
Histologically, what would be seen in reflux oesophagitis?
Squamous epithelium
Basal cell hyperplasia, elongation of papillae, increased cell desquamation
Lamina propria
Inflammatory cell infiltration (neutrophils, eosinophils, lymphocytes)
What can be the complications from reflux oesophagitis?
Ulceration
Haemorrhage
Perforation
Benign stricture (segmental narrowing)
Barrett’s oesophagus
What is Barrett’s oesophagus?
Cause:
Longstanding reflux
Risk factors:
Same as for reflux (male, Caucasian, overweight)
Macroscopy:
Proximal extension of the squamo-columnar junction
Histology:
Squamous mucosa replaced by columnar mucosa > “glandular metaplasia”
What are the types of columnar mucosa?
Gastric cardia type
Gastric body type
Intestinal type = “specialised Barrett’s mucosa”
Why is Barrett’s oesophagus concerning?
Premalignant condition with an increased risk of developing adenocarcinoma
Regular endoscopic surveillance is recommended for early detection of neoplasia
How common is oesophageal carcinoma?
8th most common cancer in the world
What are the 2 histological types of oesophageal carcinoma?
Squamous cell carcinoma
Adenocarcinoma
Which gender is oesophageal adenocarcinoma more common in?
Male 7:1
What is the aetiology for oesophageal adenocarcinoma?
Barrett’s oesophagus
tobacco, obesity
Where are oesophageal adenocarcinomas usually found?
lower oesophagus
What does an oesophageal adenocarcinoma look like?
Plaque-like, nodular, fungating, ulcerated, depressed, infiltrating
What are the risk factors for squamous carcinoma?
Tobacco and alcohol Nutrition (potential sources of nitrosamines) Thermal injury (hot beverages) HPV Male Ethnicity (black)
Where are squamous carcinomas most common?
Iran, China, South Africa, Southern Brazil
How are oesophageal cancers staged?
TNM system
How is the depth of invasion of the primary tumour scored?
pT1: tumour invades lamina propria, muscularis mucosae or submucosa pT2: tumour invades muscularis propria pT3: tumour invades adventitia pT4: tumour invades adjacent structures
How are the regional lymph node involvements scored?
pN0: no regional lymph node metastasis
pN1: regional lymph node metastasis in 1 or 2 nodes
pN2: regional lymph node metastasis in 3 to 6 nodes
pN3: regional lymph node metastasis in 7 or more nodes
What are the 4 anatomical regions of the stomach?
Cardia
Fundus
Body
Antrum
What features normally protect the stomach from gastritis>?
- Balance of aggressive
(acid) and defensive
forces - Surface mucous
- Bicarbonate secretion
- Mucosal blood flow
- Regenerative capacity
- Prostaglandins
What factors can cause increased aggression of gastritis?
Excessive alcohol
- Drugs
- Heavy smoking
- Corrosive
- Radiation
- Chemotherapy
- Infection
What factors can impair defences against gastritis?
- Ischaemia
- Shock
- Delayed emptying
- Duodenal reflux
- Impaired regulation of
pepsin secretion
What are the pathogenic mechanisms of autoimmune gastritis?
Anti-parietal cell and anti-intrinsic factor antibodies
Sensitised T-lymphocytes
What are the pathogenic mechanisms of bacterial gastritis? (H.Pylori)
Cytotoxins Liberation of chemokines Mucolytic enzymes ?Ammonia production by bacterial urease Tissue damage by immune response
What is the pathogenic mechanisms of NSAID gastritis?
Disruption of the mucus layer
What is the pathogenic mechanisms of bile reflux gastritis?
Degranulation of mast cells
What is Helicobacter Pylori?
Gram negative spiral shaped bacterium
2.5-5.0 micrometres long
4 to 6 flagellae
Lives on the epithelial surface protected by the overlying mucus barrier
Where in the stomach is H.pylori most common?
the antrum
What does h.pylori result in?
glandular atrophy, replacement fibrosis and intestinal metaplasia