WK10L4 - Gastrointestinal Pathology

Question 1

Oesophagus

Answer 1

4 layers of the GIT clearly seen in the oesophagus
Oesophageal mucosa - a NKSSE and contains small mucus secreting glands called the oesophageal glands
Closer to the stomach, the mucosa contains groups of glands called the cardiac glands which secrete additional mucus
The upper 1/3 of the oesophagus, the muscularis is exclusively skeletal muscle similar to that of the tongue
The middle portion of the oesophagus has a combination of skeletal and smooth muscle fibres
The lower 1/3 the muscularis is exclusively smooth muscle
Only the distal 1-2cm of the oesophagus, in the peritoneal cavity is covered by serosa, the rest is enclosed by loose CT of the adventitia

Question 2

Pathology of the Oesophagus

Answer 2

Lesions found in the oesophagus include;

• cancers
• heartburn
• oesophageal varices (often assoc with cirrhosis and portal hypertension)
• oesophagitis
• hiatal hernia

Question 3

Disorders of the Oesophagus - Congenital Anomalies

Answer 3

Ectopic tissue - growth of normal tissue in incorrect place
Congenital cysts - usually present as masses
Atresia - segment of the oesophagus is represented by a thin non canalised cord with a proximal pouch leading to the stomach
Fistula - attaches the lower or upper pouch to a bronchus or trachea
Oesophageal mucosal webs - protrusions of mucosa into the oesophageal lumen
Oesophageal rings - are concentric plates of tissue protruding into the lumen of the distal oesophagus
Oesophageal stenosis - fibrous thickening of the oesophageal wall at the submucosa with atrophy of the muscularis propria

Question 4

Disorders of the Oesophagus - Lesions Associated with Motor Dysfunction

Answer 4

Achalasia - failure to relax, where the smooth muscle layer of the oesophagus loses normal peristalsis
Hiatus hernia - separation of the diaphragmatic crura (fibroelastic bands) and widening of the space between the muscular crura and oesophageal wall
Lacerations - longitudinal tears in the oesophagus called Mallory-Weiss tears
Oesophagitis - inflammation of the oesophageal mucosa

Question 5

Reflux Oesophagitis (GERD) and Barrett’s Oesophagus

Answer 5

GERD = Gastro-esophageal reflux disease
GERD - reflux of gastric contents into the lower oesophagus is the most common causative factor
Barrett oesophagus
- a complication of long standing GERD
- it is the single most important risk factor for oesophageal adeno ca
- the distal sq mucosa is replaced by metaplastic columnar epithelium as a result to injury

Question 6

Oesophageal Varices

Answer 6

These are abnormal, enlarged veins in the lower part of the oesophagus
Occur most commonly as a result of those with serious liver diseases
They develop when:
- normal blood flow to the liver is slowed
- this blood then backs up into nearby smaller vessels, similar to those in the oesophagus, causing the vessels to swell
Occasionally, OV can rupture, causing life threatening bleeding
Asymptomatic until they rupture

Question 7

Criteria Required for the Diagnosis of Barrett’s Oesophagus

Answer 7

1 - endoscopic evidence of columnar epithelial lining above the gastroesophageal junction
2 - histologic evidence of intestinal metaplasia in the biopsy specimens highlighting columnar epithelium
Definitive diagnosis is only made when the columnar mucosa contains intestinal goblet cells

Question 8

Barrett’s Oesophagus - Clinical

Answer 8

Barretts is recognised as a red, velvety mucosa located between the smooth pale pink oesophageal squamous mucosa and the light brown gastric mucosa
It may exist as patches or islands extending up from the gastroesophageal junction or as a broad irregular circumferential band displacing the squamocolumnar junction
Patient’s tend to have a long history of heartburn and other reflux symptoms and appear to have massive reflux with longer reflux episodes than most reflux patients
Pathogenesis is still unclear - but is an alteration in the differentiation of stem cells of the oesophageal mucosa

Question 9

Benign Tumours of the Oesophagus

Answer 9

These are mainly mesenchymal is origin and lie within the oesophageal wall
Most common benign tumours are those of smooth muscle origin such as leiomyomas, fibromas, lipomas, haemangiomas, neurofibromas and lymphangiomas
Mucosal polyps can occur and usually arise from fibrous, vascular or adipose tissue covered by intact mucosa:
- fibrovascular polyps
- pedunculated lipomas
- squamous papillomas (can be sessile, assoc with HPV)
- inflammatory polyp (may resemble a malignant lesion)

Question 10

Malignant Tumours of the Oesophagus

Answer 10

Oesophageal cancer in Australia is a malignant tumour arising from the mucosa of the oesophagus
Most commonly it is found in the lower oesophageal junction where it adjoins the stomach
- the most common malignancy in Aus is adeno carcinoma followed by SCC
5 year survival rate for oesophageal cancer is 22%

Question 11

Pathogenesis of Oesophageal Cancer

Answer 11

Deficiency in Vit A, C, Riboflavin, Thiamine 
Fungal contamination of food
Burning hot food/drink
Alcohol consumption
Smoking
Long standing oesophagitis
Achalasia 
Ectodermal dysplasia

Question 12

Symptoms of Oesophageal Cancer

Answer 12

Early stage disease often does not show any signs or symptoms that are assoc with this disease process
Most oesophageal cancers are in advanced stages of disease and signs and symptoms may include:
- dysphagia or pain on swallowing
- episodes of choking
- weight loss
- development of upper abdominal discomfort especially when eating
- vomiting up blood
- new or worsening heartburn or acid reflux
- bloody or black coloured stools
- hoarseness or a chronic cough

Question 13

Oesophageal SCC

Answer 13

Similar to SCC in other locations and begins in an area of intraepithelial neoplasia or CIS
About 20% of SCC arise in the upper 1/3, about 50% in the middle 1/3 and 30% in the lower 1/3
Early lesions appear as small gray/white, plaque like thickenings or elevations of the mucosa
Takes months to years for these lesions to become tumorous masses

Question 14

Oesophageal SCC - Morphological Patterns

Answer 14

3 morphological patterns seen:

1. Protruded (60%)
   - polypoid exophytic lesions that protrude into the lumen
2. Flat (15%)
   - a diffuse, infiltrative form that may spread within the wall of the oesophagus resulting in thickening, rigidity and narrowing of the lumen
3. Excavated/ulcerated (25%)
   - necrotic cancerous ulcerations that excavates deep into surrounding structures and may erode into the respiratory tree

Question 15

Oesophageal Adenocarcinoma

Answer 15

A malignant tumour arising from epithelium with glandular differentiation
With increasing awareness and dx of Barrett’s oesophagus, there is recognition of adeno ca in the lower 1/3 of the oesophagus are true oesophageal cancers

Question 16

Pathogenesis of Oesophageal Adenocarcinoma

Answer 16

Barrett’s oesophagus - lifetime risk
- development of dysplasia is a critical step
- Barrett epithelial cells have a higher proliferative activity and dysplastic epithelium lose cell cycle control
- overexpression of P53, with P53 mutations occurring early, DNA damage by gastric reflux, chromosome abnormalities
Smoking
Obesity
H.plyori
Prognosis is poor with under 20% overall 5 yr survival

Question 17

Morphology of Oesophageal Adenocarcinoma

Answer 17

Usually located in the distal oesophagus and may invade the adjacent gastric cardia
Initially appear as flat or raised patches of intact mucosa
May develop large nodular masses up to 5 cm in diameter or may exhibit diffusely infiltrative or deeply ulcerative features

Question 18

Histology of Oesophageal Adenocarcinoma

Answer 18

Most lesions are mucin producing glandular tumours exhibiting intestinal type features
Less often they may be made up of diffusely infiltrative signet ring cells of gastric type or even P Diff small cell type
Multiple foci of dysplastic mucosa are frequently seen adjacent to the tumour, so random bx are performed