Cervical dysplasia is a precancerous condition in which abnormal cell growth occurs on the surface lining of the cervix or endocervical canal, the opening between the uterus and the vagina. It is also called cervical intraepithelial neoplasia (CIN). Strongly associated with sexually transmitted human papillomavirus (HPV) infection, cervical dysplasia is most common in women under age 30 but can develop at any age.