Cervical intraepithelial neoplasia (CIN) (also known as cervical dysplasia) is the potentailly premalignant stage in the dysplastic changes in the squamous epithelium of the cervix.
Grading of CIN is based on the degree of dysplasia seen in a sample of cervical tissue:
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CIN I
- similar to condylomata acuminata
- nuclear enlargement and hyperchromasia of superficial cells
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CIN II
- atypical cells are seen also in the lower layers
- pleomorphism
- increase in nuclear:cytoplasmic ration
- loss of polarity
- increase in number of mitoses
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CIN III = stage 0 cervical cancer
- entire thickness of epithelium is replaced with atypical cells with no surface differentiation.