Intraepithelial Lesions colposcopy and directed biopsy (75). This is because two-thirds of patients with this cytologic finding will have CIN 2 or greater. After colposcopically directed biopsy and determination of the distribution of the lesion, excisional or ablative therapy that addresses the entire transformation zone should be performed.
Acetowhite Epithelium Epithelium that turns white after application of acetic acid (3%– 5%) is called acetowhite epithelium (53). The application of acetic acid coagulates the proteins of the nucleus and cytoplasm and makes the proteins opaque and white (5).
The acetic acid does not affect mature, glycogen-producing epithelium because the acid does not penetrate below the outer one-third of the epithelium. The cells in this region have very small nuclei and a large amount of glycogen (not protein). These areas appear pink during colposcopy. Dysplastic cells are those most affected. They contain large nuclei with abnormally large amounts of chromatin (protein). The columnar villi become “plumper” after acetic acid is applied, making these cells easier to see. They appear slightly white, particularly in the presence of the beginning signs of metaplasia. The immature metaplastic cells have larger nuclei and show some effects of the acetic acid. Because the metaplastic epithelium is very thin, it is not as white or opaque as CIN but instead appears gray and filmy (5).
Leukoplakia Translated literally, leukoplakia is white plaque (5). In colposcopic terminology, this plaque is white epithelium, visible before application of acetic acid. Leukoplakia is caused by a layer of keratin on the surface of the epithelium. Immature squamous epithelial cells have the potential to develop into keratin-producing cells or glycogen-producing cells. In the vagina and on the cervix, the normal differentiation is toward glycogen. Keratin production is abnormal in the cervicovaginal mucosa. Leukoplakia can be caused by HPV; keratinizing CIN; keratinizing carcinoma; chronic trauma from diaphragm, pessary, or tampon use; and radiotherapy.
Leukoplakia should not be confused with the white plaque of a monilial infection, which can be completely wiped off with a cotton-tipped applicator. The most common reason for leukoplakia is HPV infection (Fig. 19.8). Because it is not possible to see through the thick keratin layer to the underlying vasculature during colposcopy, such areas should undergo biopsy to rule out keratinizing carcinoma.
CHAPTER 19 Intraepithelial Disease of the Cervix, Vagina, and Vulva
Figure 19.8 Colposcopy of cervical intraepithelial neoplasia 2 (CIN 2) associated with human papillomavirus (HPV) infection of the cervix.
Punctation Dilated capillaries terminating on the surface appear from the ends as a collection of dots and are referred to as punctation (Fig. 19.9). When these vessels occur in a well-demarcated area of acetowhite epithelium, they indicate an abnormal epithelium— most often CIN (5) (Fig. 19.10). The punctate vessels are formed as the metaplastic epithelium migrates over the columnar villi. Normally, the capillary regresses; however, when CIN occurs, the capillary persists and appears more prominent.
Figure 19.9 Diagram of punctation. The central capillaries of the columnar villi are preserved and produce the punctate vessels on the surface.
Figure 19.10 Human papillomavirus (HPV)/cervical intraepithelial neoplasia 2 (CIN 2) presents as a white lesion with surface spicules.