Oral epithelial dysplasia

Question 1

What is the normal histology of the oral epithelium?

Answer 1

• Replicating basal cells (keratocyte) sit on a basement membrane
• Cells at the bottom are more rectangular/ columnar and nucleus is visibile
• as cells replicate they are pushed towards the surface → cells get flatter (nucleus is not visible)

Question 2

What are the normal features of a basal cell (keratocyte)

Answer 2

• Nucleus exhibits polarisation (usually at the base)

Question 3

How is the ratio of nucleus: cytoplasm relevant of a basal cell

Answer 3

• Cells with more abnormalities have a BIGGER nucleus

-Cells replicating a lot have a BIGGER nucleus

Question 4

What dictates the colour and texture of the epithelium

Answer 4

thickness of epithelial cell layer

Question 5

What does a red lesion indicate about the thickness of the epithelial cell layer

Answer 5

thin epithelium

Question 6

What does a white lesion indicate about the thickness of the epithelial cell layer

Answer 6

Thick epithelium

Question 7

What are the features of dysplasia at a cellular level

Answer 7

• Larger nucleus
  -Increased nucleus: cytplasmic ratio
• Lose polarity
  -More mitotic figures

Question 8

What is the purpose of a biopsy and how is it conducted for testing?

Answer 8

Fine needle aspiration: take cells out the tissues

Purpose: assess cells and see their arrangement

Question 9

What features on a biopsy indicate dysplasia

Answer 9

1. Disordered maturation (loss of polarity, basaloid appearance throughout whole epithelium)
2. Abnormal cell size/ shape (polymorphism, reduced cell cohesion)
3. Abnormal replication (nuclear hyperchromatism, increased nuclear size, mitotic figures)
4. Abnormal function: abnormal keratinisation (appear white)

Question 10

What is meant by low grade dysplasia

Answer 10

Normal cells at the top, abnormal cells at the bottom

Question 11

What is meant by high grade dysplasia

Answer 11

Abnormal cells through full thickness of epithelium

Question 12

What is rete ridges and their function?

Answer 12

Indentations of basal layer in basement membrane at the interface between epithelial and sub epithelial tissues

function: structural strength to epithelium

Question 13

True or false: dysplasia can improve & regress spontaneously

Answer 13

TRUE:
- Dysplasia can
- Cancer DOESN’T get better

Question 14

What dysplastic changes occur to rete ridges

Answer 14

Drop shaped rete ridges: teardrops where rete ridges are pushed down in subepithelial tissues

Question 15

What is the difference between invasive carcinoma and carcinoma in-situ

Answer 15

Invasive carcinoma: You have cancer, breach in basement membrane: abnormal cells invading through basement membrane

Carcinoma in-situ:
- very abnormal tissues,basement membrane is not breached (not cancer)

Question 16

What are the causes of dysplasia

Answer 16

• spontaneous mutations
• toxins/ radiation
• genetic problems
• tobacco smoke
  -alcohol
• betel nut (Paan)
  -Immune suppression
• Lichen planus

Question 17

How does lichen planus affect dysplasia

Answer 17

Majority of people with lichen planus will not develop cancer/ oral cancer

1 in 100 do (risk factor)

Question 18

What are the features of hyperplasia and how is it treated

Answer 18

Cells under control, thickening of epithelium in response to heat, chemical and mechanical trauma

treatment: removal of cause

Question 19

What are the features of mild/ moderate
(low grade) dysplasia

Answer 19

• Abnormal cells
• polymorphism
• increased nucleus: cytoplasm ratio
• abnormal cell adhesion

-mitotic figures

• Mild:/ low:
  confindement to 1/3 basememnt

moderate: 2/3 basement membrane, gaps between cells, dark cells lower down

Question 20

How is mild/ moderate dysplasia treated

Answer 20

1. Address risk factors e.g smoking cessation etc
2. Observe and monitor low grade lesions
3. High grade lesions remove

Question 21

What are the features of severe dysplasia

Answer 21

• High grade dysplasia (no polarity, large nucleus, basaloid cell appearance)
• Basement membrane in tact
• high cancer risk

Question 22

What is the distinguishing features of SCC & its management

Answer 22

Breach of basement membrane

-surgery, radiotherapy, chemotherapy (node involvement)