pathogenesis of head and neck cancer 3 Flashcards
Describe oral epithelial dysplasia (OED)
is a spectrum of architectural and cytological epithelial changes resulting from accumulation of genetic alterations, usually arising in a range of oral potentially malignant disorders (OPMD) and indicating a risk of malignant transformation to squamous cell carcinoma (SCC)
Which sites are associated with high risk of malignant transformation
- Lateral border of tongue
- Ventral tongue
- retromolar area
- floor of mouth
What are the histological features of epithelial dysplasia?
1) Nuclear and cellular pleomorphism
2) Alteration in nuclear/cytoplasmic ratio (invariably an increase)
3) Nuclear hyperchromatism
4) Prominent nucleoli
5) Increased and abnormal mitoses
6) Loss of polarity of basal cells
7) Basal cell hyperplasia
8) Drop-shaped rete pegs i.e. wider at their deepest part
9) Irregular epithelial stratification or disturbed maturation
10) Abnormal keratinization ‘Dyskeratosis’ - cell starts to keratinize before the surface is reached
describe epithelial dysplasia grading
- Mild, moderate, severe
- (severe = carcinoma in situ)
- Some pathologists use a binary system ‘Low grade/High grade’
- Grading is subjective - considerable intra and interobserver variation
Describe mild, moderate and severe dysplasia
- Mild - disorganisation, increased proliferation and atypia of basal cells
- Moderate - more layers of disorganised basaloid cells, atypia, suprabasal mitoses
- Severe - very abnormal, affects full thickness of epithelium
- However, defining dysplasia grade only in this manner oversimplifies the complexity of grading
Describe features of epithelial dysplasia
All the features of dysplasia may be seen in oral squamous cell carcinoma, however in dysplasia the atypical cells are confined to the surface epithelium
In squamous cell carcinoma, the atypical cells invade into the adjacent tissues
