Potentially malignant lesions and oral cancer Flashcards
What does the histology of the oral epithelium look like?
What are the potentially malignant conditions of the oral cavity?
- Leukoplakia
- Proliferative verrucous leukoplakia
- Erythroplakia
- Oral lichen planus
- Oral submucous fibrosis
- Actinic Cheilitis (lip only)
- Palatal lesion of reverse cigar smoking
- Discoid lupus erythematosus
- Hereditary disorders eg dyskeratosis congenita
What is this?
Leukoplakia: any white lesion that cannot be identified either pathologically or clinically and is not related to physical or chemical causes other than smoking.
What is the clinical classification of leukoplakia?
HOMOGENEOUS: a predominantly white leukoplakia of generally uniform appearance and texture even though surface irregularities may be present
•NON-HOMOGENEOUS: either a predominantly white
or
•ERYTHROLEUKOPLAKIA: white and red lesion with an irregular texture throughout. Lifetime risk of transformation to OSCC is much higher compared to homogenous leukoplakia.
What is this?
Extensive leukoplakia.
What are the stats for leukoplakia?
- Leukoplakia has
- Seen in 1-5% of population
- < 2% OPMD progress to cancer each year
- Tongue, FOM, retro molar, soft palate are higher risk vs other intraoral sites
What factors would increase the risk profile of a Leukoplakia?
- High risk sites for oral cancer such as floor of mouth and lateral aspect of the tongue.
- Non homogenous texture (non homogenous leukoplakia)
- Mixed red and white non homogenous areas. (erythroleukoplakia)
- Raised compared to surrounding mucosa. •Induration at base of leukoplakia and
surrounding tissues.
- Verrucous (rough, “rugpile like”) surface. •Presence of ulceration.
- Absence of tobacco use to account for leukoplakia increases risk
- Age: older patients more at risk.
- Sex: female patients more at risk.
- Smoking
What is the risk of malignant transformation depending on the degree of dysplasia?
None = 1%
Mild (1/3rd of epithelium dysplastic) = 5%
Moderate (1/2 to 2/3rds) = 15%
Severe (top to bottom of epithelium) = 25%
What is dysplasia?
It can be seen down the microscope and is the amount of ‘disorder’ of cells and disruption of cell layers. There are three categories:
- dysplasia of the epithelial architecture
- cytological features of dysplasia
- functional aspects of dysplasia
You can get basal cell hyperplasia which is when the basal cell layer thickens and goes up into the stratume spinosum (prickle cell layer) and down into the connective tissue (creating drop shaped rete ridges). Does NOT break throught the basement membrane though, if it does the invasion becomes malignant (no longer termed dysplastic).
In dysplasia you also get loss of polarity of cells, the cell nuclei move away from the basement membrane and towards the stratum spinosum (prickle cell layer). Also get darkening of the cells (change in colour on histology slide).
What is the cytology of dysplasia?
- Pleomorphic cells
- Increase in cell size
- Loss of polarity
- Loss of intercellular adhesion
- Nuclear pleomorphism and hyperchromatism
- High nucleus : cytoplasm
- Prominent nucleoli
What are the functional aspects of dysplasia?
• Mitotic figures:
- increased frequency
- mitoses in suprabasal
- abnormal forms
• Aberrantkeratinisation:
- dyskeratosis (keratin production in epithelial layer normally just on the outside surface, in dyskeratosis keratin is seen anywhere in the epithelial layer. This indicates it’s more likely to be malignant.)
What is this?
Normal epithelia
What is this?
Keratosis/hyperplasia
What is this?
Mild dysplasia
What is this?
Moderate dysplasia