An Overview on Cervical Intraepithelial Neoplasia (CIN)

Abstract

Background: Cervical intraepithelial neoplasia (CIN) represents premalignant changes in the squamous epithelium of the cervix and is strongly associated with persistent infection with high-risk human papillomavirus (HPV), particularly types 16 and 18. CIN is histologically classified into three grades (CIN 1, CIN 2, and CIN 3) based on the extent of epithelial dysplasia. While low-grade lesions (CIN 1) often regress spontaneously, high-grade lesions (CIN 2 and CIN 3) carry a significant risk of progression to invasive cervical carcinoma if left untreated. Early detection through cervical cytology (Pap smear), HPV testing, and colposcopic evaluation has markedly reduced the incidence and mortality of cervical cancer worldwide. Management strategies depend on lesion grade, patient age, reproductive plans, and associated risk factors, and range from observation to ablative or excisional procedures such as loop electrosurgical excision procedure (LEEP) or cold knife conization.