Figure 20. Cervical intraepithelial neoplasia stage I–II after application of acetic acid.

Aceto-white lesion in the transformation zone abutting the squamo-columnar junction (dashed line). The white area is dense and has feathery margins (arrows), possibly with some mosaic pattern (ovals). This finding probably represents cervical intra-epithelial neoplasia (CIN) stage one to two. CIN refers to the premalignant neoplastic changes taking place in the squamous epithelium in the transformation zone of the cervix before the possible development of cervical squamous carcinoma. These changes can be divided into three groups based on the proportion of epithelium thickness involved in the dysplastic process. Early stages of CIN may be confused with homogenous yellow areas of the sandy patches, and late stages may involve some of the same vessel patterns that can be seen in schistosome lesions [6]. However, the schistosome lesions are not aceto positive, and they are not confined to the transformation zone.