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Normal Colposcopic Findings
Squamous epithelium:
Squamous epithelium is the main histological type of epithelium lining the female lower genital tract. Stratified squamous epithelium is composed of squamous cells arranged in four distinct layers, known as basal, parabasal (suprabasal), intermediate and superficial layers. CIN lesions have their origin in the basal cells, explaining their histological resemblance to basaloid cells.
Mature
Mature, differentiated squamous epithelum has low content of proteins and high content of glycogen. Due to low contents of proteins normal epithelium remains pink after the application of 3-5% Acetic acid. High contents of glycogen produce brown color in reaction with Iodine.
Atrophic
In postmenopaual period, due to low estrogen levels, normal squamous epithelium undergoes atrophic changes. There is a pronounced atrophy of the vaginal epithelium, and the connective tissue becomes dense. Therefore, the colposcopic interpretation of atrophic vagina can be very difficult. The epithelium is thin, pale and generally smooth. Vaginal folds are flattened and the vaginal wall is less elastic. It is easy to see the blood vessels of the stroma that lies beneath the epithelium. Blood vessels and epithelium are very vulnerable, and petechial hemorrhage and loss of surface epithelium, which are often seen, easily arise when placing a speculum. The application of acetic acid, too, can cause a feeling of intense burning.
Even gentle examination can cause trauma easily, leaving small erosions or lacerations along side walls of the vagina. Denuded stroma is red and when these traumatic lesions are severe, general appearance may be suspicious to neoplasia. Atrophic changes are reversible. The use of local hormonal therapy can improve the colposcopic and cytologic picture of atrophic epithelium.
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