Potentially Malignant Disorders and Oral Cancer

Question 1

what is a potentially malignant lesion?

Answer 1

altered tissue in which cancer is more likely to form

Question 2

what is a potentially malignant condition?

Answer 2

generalized state with increased cancer risk

Question 3

What systemic conditions make a person more likely to develop cancer? [potentially malignant conditions]

Answer 3

• lichen planus [erosive variety]
• oral submucous fibrosis
• iron deficiency [causes atrophy of oral epithelium]
• tertiary syphilis [develops white patch on tongue]

Question 4

What can cause oral submucous fibrosis?

Answer 4

Chewing betel nut which causes
- atrophy
- abnormal collagen
- restricted mouth opening
- xerostomia
- increased cancer risk

Question 5

what type of leukoplakia can be potentially malignant?

Answer 5

• chronic hyperplastic candidoses
• proliferative verrucous leukoplakia

Question 6

Where is chronic hyperplastic candidosis found? What causes it?

Answer 6

• caused by Candida albicans
• found on the commissures of the mouth

Question 7

What typically causes chronic hyperplastic candidosis?

Answer 7

smokers

Question 8

What investigation should you do when a pt has chronic hyperplastic candidosis?

Answer 8

Biopsy!!
- check for dysplasia as these lesions can become malignant

Question 9

How does hyperplastic candidosis appear under microscope?

Answer 9

• excessive keratin deposits (where epithelium is generally not keratinised)
• acanthosis of epithelium (stratum spinosum layer)
• inflammatory cells within the lamina propria (macrophages, neutrophils etc)

Question 10

What specific stain is needed to demonstrate candida albicans hyphae clearly?

Answer 10

Periodic Schiff Stain (PAS)

Question 11

How is chronic hyperplastic candidosis treated?

Answer 11

1. systemic antifungal
   - Fluconazole 1x 50mg everyday for 2 weeks
2. biopsy
3. smoking cessation
4. observe

Question 12

do all cases of oral cancer have potentially malignant lesions beforehand?

Answer 12

NO
- most oral carcinomas in UK arise in clinically normal mucosa

Question 13

What sites of oral cavity are higher risk of leukoplakia becoming malignant?

Answer 13

• floor of mouth
• tongue

Question 14

What sites of oral cavity are lower risk of leukoplakia becoming malignant?

Answer 14

buccal mucosa

Question 15

Not every leukoplakia will develop into cancer, what markers may suggest that a lesion will?

Answer 15

• age and gender (older)
• idiopathic
• site [tongue & FoM]
• non-homogenous lesions

Question 16

What predictor markers do we look for in histopathology that suggest malignant change?

Answer 16

• dysplasia
• atrophy
• candida infection

Question 17

what molecular markers may determine if a lesion will become malignant?

Answer 17

HPV & p53 (apoptosis)

Question 18

What is dysplasia ?

Answer 18

disordered maturation (growth) in a tissue

Question 19

What is atypia?

Answer 19

changes in cells

Question 20

For a potentially malignant lesion, what is the criteria for diagnosis?

Answer 20

• abnormal architectural changes
• cytological abnormalities (cellular atypia)

Question 21

What does grading refer to?

Answer 21

Histopathology

Question 22

What does staging refer to?

Answer 22

Clinical assessment

Question 23

What is basal hyperplasia?

Answer 23

increased basal cell numbers

Question 24

How does histopathology appear in mild dysplasia?

Answer 24

• changes in architecture of lower third
• mild atypia [pleomorphism and hyperchromatisim]

Question 25

How does histopathology appear in moderate dysplasia?

Answer 25

- architectural changes extend into middle third - moderate atypia

Question 26

How does histopathology appear in severe dysplasia?

Answer 26

- architectural changes extending into upper third - severe atypia & numerous mitosis

Question 27

How would a carcinoma-in-situ appear under the microscope?

Answer 27

- abnormal architecture = full thickness of viable cell layers - pronounced cytological atypia

Question 28

How are potentially malignant lesions / oral cancer detected?

Answer 28

Visual oral examination alongside biopsy & histopathological investigation

Question 29

What common diagnostic tests are used in clinical practise to investigate potentially malignant lesions?

Answer 29

- vital staining - oral cytology - optical imaging

Question 30

What are the two main factors that contribute to carcinogenesis?

Answer 30

- genetic predisposition - environmental factors

Question 31

what are oncogenes?

Answer 31

normal genes that produce growth factors in cells - in cancer these can become activated and contribute to tumour growth

Question 32

Explain Knudsons two hit theory:

Answer 32

First hit = Individuals inherit one mutated copy of a tumor suppressor gene from one of their parents. This mutation is present in all cells of the body and predisposes the individual to cancer development. Second hit = A second, somatic mutation occurs in the remaining functional copy of the tumor suppressor gene within a specific cell or tissue. This second mutation results in the complete loss of function of the tumor suppressor gene in the affected cell, leading to uncontrolled cell growth and tumor formation.

Question 33

What genes are involved in driving oral cancer?

Answer 33

- oncogenes - tumour suppressor genes - Tp53 mutation - genes that regulate apoptosis - genes involved in DNA repair - miRNA

Question 34

What are epigenetic changes?

Answer 34

chemical changes in DNA, such as methylation and modification of the histones that package DNA

Question 35

What are the six genetic hallmarks of cancer?

Answer 35

- self sufficiency and growth signals - evading apoptosis - insensitivity to anti-growth signals - tissue invasion and metastasis - sustained angiogenesis - limitless replicative potential

Question 36

What % of oral cancer is squamous cell carcinoma?

Answer 36

95% of oral cancer cases

Question 37

How does oral cancer spread?

Answer 37

1. local extension of disease 2. lymphatic spread 3. haematogenous spread

Question 38

If a histopathological view of oral cancer has a non-cohesive front, what may this suggest?

Answer 38

The cancer has spread to the lymph nodes

Question 39

What system is used for clinical staging of oral cancer?

Answer 39

TNM staging - T = size - N = lymph node involvement - M = metastasis

Question 40

What are some subtypes of oral squamous cell carcinomas?

Answer 40

- basaloid squamous (associated with HPV) - verrucous carcinoma - spindle cell