OC 11 - pathogenesis of HNC 3 Flashcards
(23 cards)
What is dysplasia?
a pre-malignant process
can be identified in many tissues
In tumour growth, what is the “initial event”?
initial event is where DNA damage occurs
In tumour growth, what is “mild dysplasia”?
damage has led to atypical proliferation of cells, but this is contained within the epithelium
In tumour growth, what is “severe dysplasia”?
full thickness of epithelium becomes involved - not invasive malignancy yet though because the tumour cells are still in the surface epithelium and havent breached the basement membrane
In tumour growth, what is “invasive malignancy”?
tumour cells have breached the basement membrane and are invading surrounding tissue
What is epithelial dysplasia?
a premalignant process - indicates a risk of developing carcinoma
In epithelial dysplasia, where are atypical epithelial alterations limited to?
limited to the surface squamous epithelium
What are architectural changes?
maturation and differentiation
What are cytological changes?
changes in cells
What is the key point to remember about epithelial dysplasia!
cells show abnormal features that are also seen in cancer cells but they do not yet possess the ability to invade adjacent normal tissues
What are the histological features of epithelial dysplasia?
- nuclear and cellular pleomorphism
- alteration in nuclear/cytoplasmic ratio (invariably an increase)
- nuclear hyperchromatism
- prominent nucleoli
- increased and abnormal mitoses
- loss of polarity of basal cells
- basal cell hyperplasia
- drop-shaped rete pegs
- irregular epithelial stratification or disturbed maturation
- abnormal keratinisation (dyskeratosis)
- loss/reduction of intercellular adhesion
What is nuclear and cellular pleomorphism?
variation in the size and shape of the nuclei and the cells themselves
What are ‘drop-shaped’ rete pegs?
wider at their deepest part
What is dyskeratosis?
cells start to keratinise before the surface is reached
What makes oral epithelial dysplasia different to oral SCC?
in dysplasia the atypical cells are confined to the surface, in SCC the atypical cells invade into the underlying connective tissue
What are the 3 categories in the WHO 2017 grading of epithelial dysplasia?
mild
moderate
severe (= carcinoma in situ)
What are the WHO 2017 gradings of epithelia dysplasia based on?
based on 1/3 of epithelium
What are the characteristics of mild dysplasia?
disorganisation, increased proliferation and atypia of basal cells
basal 1/3 of epithelium
What are the characteristics of moderate dysplasia?
more layers of disorganised basaloid cells, atypia, suprabasal mitoses
extending to 2/3rds of the epithelium (basal and middle third)
What are the characteristics of severe dysplasia?
very abnormal, affects full thickness of epithelium (all 3rds)
What are oral potentially malignant disorders?
oral mucosal lesions that have a potential risk of developing into oral SCC
What are some oral potentially malignant disorders?
- Leukoplakia
- Erythroplakia
- Erythroleukoplakia
- Oral submucous fibrosis
- Syphilitic glossitis
- Dyskeratosis congenita
- Chronic candidiasis
- Lichen planus
- Discoid lupus erythematosus
- Smokeless tobacco keratosis
- Palatal lesions associated with reverse smoking
- Actinic keratosis (lip only)
What is oral submucous fibrosis?
pale fibrous bands
- progressive deposition of collagen in the submucosal tissue, also associated with atrophy of the surface epithelium
