Cervical intraepithelial neoplasia classification

Grades
CIN has three distinct grades:
 * CIN1 (Grade I), the least risky type, represents only mild dysplasia, or abnormal cell growth and is considered a low grade squamous intraepithelial lesion (LGSIL). . It is confined to the basal 1/3 of the epithelium.
 * CIN2 (Grade II), as well as CIN III, are considered high grade squamous intraepithelial lesions (HSIL). CIN2 represents moderate dysplasia, and is confined to the basal 2/3 of the epithelium
 * CIN3 (Grade III): In this lesion, severe dysplasia spans greater than 2/3 of the the entire epithelium, and may involve the full thickness. This lesion may also be referred to as cervical carcinoma in situ.