The goal of colposcopy is to identify the cervical intraepithelial neoplasia (CIN) and invasive cancer. The term CIN is used for the squamous precancers; it is not used for the adenocarcinoma precursors. The CIN cells have nuclei that are larger and darker than normally maturing squamous cells. The application of 5% acetic acid causes the cytoplasm to shrink and make the nuclei even more prominent. When the light of the colposcope hits the CIN, the light is reflected back like a mirror, giving the white appearance. The normal cells are translucent and the light goes through to the blood vessels below, and the cervix appears pink. The columnar cells will appear red because they are a single layer over the vascular network. The tech figure (Tech Fig. 15.4) shows a illustration depicting the CIN versus normal epithelium. The acetic acid should be applied for 1.5 to 2 minutes with the scope in focus and the examiner watching the T-zone for acetowhite change. In addition to the appearance of acetowhite, the vascular changes of punctation and mosaic may appear. Punctation vessels are formed by the preservation of the columnar vessels in the neoplastic epithelium (Tech Fig. 15.5). The mosaic vessels are formed by the network of vessels around the glands that the CIN replaces (Tech Fig. 15.6).

The colposcopist will observe for up to 5 minutes with reapplication of acetic acid, if needed. The T-zone will be described as normal if no lesion is seen or abnormal if a lesion is seen. The examination will be termed satisfactory if the entire T-zone is seen and unsatisfactory if it is not.

The most common reason for unsatisfactory is that the lesion goes into the cervical canal. If a lesion is seen, it will be described as low grade if it is CIN 1 or high grade if it is CIN 2 or 3. It will be described as suspect invasive cancer if there are ulcerations, abnormal vessels, or a necrotic surface. The findings used to determine grade are the denseness of the acetowhite change, the distinctness of the border, and the appearance of vascular changes of punctation and mosaic. In 2012, the International Federation of Colposcopy and Cervical Pathology (IFCPC) added three additional signs of CIN 3. They are cuffed-gland sign, inner border sign, and ridge sign.

Low-grade lesions have less dense acetowhite, indistinct borders, and do not have punctation or mosaic (Tech Fig. 15.7). High-grade lesions include CIN 2 and CIN 3. Since CIN 2 lesions may not be treated in young women, it may be useful to separate them from CIN 3 based on the IFCPC criteria above. Additional criteria are the coarseness of the punctation and mosaic. An example of CIN 2 is shown in the tech figure (Tech Fig. 15.8). It has a distinct border with dense acetowhite, but there are no vessels and none of the other IFCPC signs of CIN 3. Lugol solution is used to allow the colposcopist to see the border distinctly and differentiate it from CIN 1 (Tech Fig. 15.9). Punctation and mosaic are shown in tech figure (Tech Fig. 15.10). Here, a cotton-tipped applicator is used to lift the anterior lip of the cervix
to see that the examination is satisfactory. This is CIN 3. The tech figure (Tech Fig. 15.11) shows the inner border sign of an oncogenic HPV. Peripheral to that is the irregular border of a non-oncogenic HPV. This border is indistinct and not thick. There is mosaic as one looks toward the squamocolumnar junction. The tech figure (Tech Fig. 15.12) shows a higher power

of the mosaic area of this patient. The tech figure (Tech Fig. 15.13) shows the cuffed-gland sign and the ridge sign. Both are indicative of CIN 3. The tech figure (Tech Fig. 15.14) shows cuffed glands, irregular mosaic, and another finding called rag sign where the epithelium has peeled away from the stroma. The tech figures (Tech Figs. 15.15, 15.16 and 15.17) show the same patient before acetic acid, after acetic, and when the acetic is wearing off. It shows the thick acetowhite can cover the mosaic and emphasizes why the examiner must observe for up to 5 minutes. The tech figure (Tech Fig. 15.18) shows a large CIN 3 that does not have much acetowhite effect but has cuffed glands, mosaic, and extends into the endocervix. These extensive lesions are difficult to encompass with the wire loops used for loop electrosurgical

excision procedure (LEEP), and a cone should be considered to rule out invasion. The tech figures (Tech Figs. 15.19 and 15.20) are describing the same patient. Again there is very little acetowhite, but there are cuffed-gland openings. This is a large lesion but the examination is satisfactory. The tech figures (Tech Figs. 15.21 and 15.22) are describing the same patient.