Colposcopic Findings

Chapter 6

Colposcopic Findings

6 Colposcopic Findings

It is important to appreciate that very similar colposcopic appearance can be produced by different biologic processes. Understanding this requires knowledge of the underlying histology. The relationship between cervical histology and pathology and colposcopic diagnosis is fundamental and reciprocal.

6.1 Normal Colposcopic Appearances

6.1.1 Original Squamous Epithelium

Like other normal superficial squamous epithelia, the native, original squamous epithelium of the uterine cervix is smooth and uninterrupted by gland openings (Fig. 6.1). This sets it apart from normal squamous epithelium that has arisen through metaplasia. More detailed observation of a surface covered by epithelium of metaplastic origin shows gland (crypt) openings and retention cysts, which indicate that the area was originally occupied by columnar epithelium (Figs. 6.2 and 6.3a–c). The original squamous epithelium during the reproductive period displays a reddish color that can vary from pale to intense pink during the various phases of the menstrual cycle. It stains deep brown with iodine, reflecting its glycogen content (Fig. 6.3c).

The so-called portio rugata is seen especially during adolescence. The cervix is dome-shaped, with a dimple-like os but can expand distally to resemble a mushroom (Fig. 6.4). Sometimes the surface looks like a cockscomb (Fig. 6.5a, b). This is probably an incidental finding without clinical relevance.

6.1.2 Atrophic Squamous Epithelium

After menopause, in the absence of estrogen, the squamous epithelium becomes thin and devoid of glycogen, and the stromal blood supply diminishes. These changes result in a pale epithelium that can show a fine network of capillaries (Fig. 6.6a). The epithelial thinning and loss of glycogen are patchy, resulting in a stippled appearance with iodine because of its irregular uptake (Fig. 6.6b). In older women, the epithelium assumes a uniform light brown to yellow color as a result of complete loss of glycogen (Fig. 6.7). The thin epithelial covering is fragile and makes the terminal vessels vulnerable to minor trauma, which can result in erosions and subepithelial hemorrhages (Fig. 6.8).

6.1.3 Ectopy (Columnar Epithelium)

Ideally, the original squamocolumnar junction (SCJ) is situated at the external os. Depending on the size, shape, and patulosity of the external os, varying portions of the canal may be visible. In patulous cervices, the architecture of endocervical mucosa can be seen clearly (Fig. 6.9).

In adolescents and young women, the columnar epithelium is frequently situated on the ectocervix at some distance from the external os. This is referred to as ectopy. In cases of marked eversion of the endocervical mucosa, its rugose architecture becomes evident (Figs. 6.106.12a, b).

Ectopy appears classically as a “red patch” (Fig. 6.2a). Grossly, it may look suspicious to the inexperienced examiner. More detailed colposcopic examination shows its unique papillary architecture, which identifies its real nature. Ectopy does not stain with iodine (Fig. 6.2b).

Ectopy is usually covered by mucus secreted by the columnar epithelium. Acetic acid helps to remove the mucus (see Chapter 3), revealing the distinctive papillary structure. Acetic acid also causes the tissue to swell, throwing the mucosal architecture into sharp relief and giving the papillae a grapelike appearance. The intense red of the red patch changes to pink or whitish (Figs. 6.3 and 6.13).

The SCJ is usually sharp and step-like (Figs. 6.2, 6.9, and 6.13). Careful inspection often reveals a slender, white margin and gland openings, which indicates the initiation of transformation (Figs. 6.3, 6.11, and 6.14). It is important to pay close attention to the margins of ectopy so as not to overlook significant colposcopic lesions.

Ectopic columnar epithelium is less resilient and more vulnerable to trauma than squamous epithelium. It is subject to contact bleeding at speculum examination (contact bleeding should also make the examiner consider the possibility of cancer). Although neoplastic papillary fronds tend to be coarse and irregular, they can be mistaken for benign changes.

The influence of exogenous and endogenous sex steroids on the transformation of the columnar epithelium has been studied longitudinally (Fig. 6.15a–d). Estrogen-containing oral contraceptives appear to have a positive and enhancing effect on ectopy, and women who discontinue contraceptives show transformation in a relatively brief time (Fig. 6.16a, b).

6.1.4 Transformation Zone

The transformation zone (TZ) can appear as a nonspecific red area. Sometimes there is a fine vascular pattern (Fig. 6.17a). Application of acetic acid turns the previously red epithelium grayish white. Within the TZ are openings of cervical glands (crypts) and small islands of residual columnar epithelium. The demarcation from the original squamous epithelium is indistinct (Fig. 6.17b).

The process of transformation characteristically begins at the SCJ. The flat epithelial margin around the periphery of an ectopy can be distinguished from the original squamous as well as columnar epithelium by its variable color and by the presence of gland openings (Figs. 6.2, 6.6, and 6.186.20).

The surface contour of an ectopy changes as transformation takes place. The papillae become coarse and fused, resulting in only slight fissuring of the surface. These changes signify the initiation of squamous metaplasia. Fields of metaplastic epithelium within a TZ may vary widely in their maturation, easily verifiable by application of iodine (the Schiller’s test), which is a sensitive indicator of epithelial maturity (Fig. 6.20b).

The topographic progression of transformation can be haphazard, and its stage of development can vary markedly from one part of the periphery to another. Islands of squamous epithelium can appear in a sea of columnar epithelium; these must have arisen by metaplasia (Figs. 6.15a–d, 6.16a, b, and 6.19). The metaplastic epithelium can form tongues or fingerlike processes that interdigitate with intact columnar epithelium (Fig. 6.21). Even when most of an ectopy is fully transformed, small islands of columnar epithelium can remain; this appearance is referred to as TZ with ectopic residuals (Fig. 6.22). Longitudinal study of the TZ over years is particularly informative (Figs. 6.15 and 6.16).

The transformation of an ectopy from columnar to squamous epithelium does not always proceed to completion. Areas of the newly formed squamous epithelium can be fully mature, whereas other parts of an ectopy can remain columnar for long periods (Fig. 6.23). The new SCJ is again situated at the external os. Squamous epithelium of metaplastic origin can be distinguished from original squamous epithelium by the presence of gland openings, more prominent vessels (Fig. 6.24), or retention cysts (Fig. 6.25). Undulations from numerous retention cysts (nabothian follicles), with long vessels coursing over their surface, are also characteristic (Fig. 6.26). The vasculature in such cases is so typical that the presence of deep-seated and otherwise invisible cysts can be easily inferred (Figs. 6.132 and 6.133).

6.2 Abnormal Colposcopic Findings

6.2.1 Acetowhite Epithelium

The 2011 International Federation for Cervical Pathology and Colposcopy nomenclature distinguishes between thin and dense acetowhite epithelium, the former being a minor change and the latter a major change. Rapid appearance of acetowhitening is also considered a major change. Acetowhite epithelium does not show mosaic, punctation, or leukoplakia. It does usually contain gland openings and even retention cysts. It usually corresponds to the normal TZ but differs from it in several important aspects. It is characterized by the hallmarks of transformation (e.g., gland openings, retention cysts, residual islands of columnar epithelium) but differs from normal in one or more of the following features:

• A dull to yellow-red color before application of acetic acid.

• A more pronounced color change from red to white with acetic acid application.

• Cuffed gland openings.

• A richer vascularity with occasional atypical vessels.

• A characteristic canary yellow tinge after application of iodine, with at least part of its circumference being sharply demarcated.

These criteria do not always signify the development of atypical epithelium. Transformation can also result in a metaplastic epithelium with only slight keratinization and no elongated stromal papillae and thus will not appear colposcopically as keratosis, punctation, or mosaic. Compared with original squamous epithelium, metaplastic epithelium undergoes a more distinct color change with acetic acid, and its junction with original squamous epithelium is sharply defined (Fig. 6.27). In spite of these differences, it is not always possible to distinguish colposcopically between metaplastic epithelium and squamous intraepithelial lesion (SIL). Even the whitish epithelium of high-grade SIL (HSIL) may be only discrete (thin acetowhite epithelium) so that it can be difficult to distinguish from a normal TZ (Fig. 6.28).

There may be subtle hints of the presence of white epithelium before application of acetic acid. Any shade of red other than the fresh red of the normal TZ should be viewed with suspicion. Grayish red tones, which give the TZ an opaque appearance, and yellow shades, which are probably due to marked inflammatory infiltration of the stroma (Figs. 6.29 and 6.30a), are particularly worrisome. In such cases, acetic acid usually induces a distinct white color change and reveals sharp borders (Figs. 6.29b and 6.30b). A rich vascular bed suggests unusual transformation but is not pathognomonic of epithelial atypia (Fig. 6.31).

The best diagnostic criterion is the acetic acid test. The more marked and the more rapid the color change and the greater the swelling, the greater the likelihood of epithelial atypia (dense acetowhite epithelium; Figs. 6.30b, 6.32, and 6.33). However, the spectrum of color changes is wide (Figs. 6.34 and 6.35a).

6.2.2 Atypical Transformation Zone

The term atypical transformation zone was previously used as an umbrella designation for practically all abnormal colposcopic appearances such as leukoplakia, punctation, and mosaic, as these also occur outside the TZ. The term is no longer part of the official nomenclature.

6.2.3 Mosaic

The term mosaic refers to a colposcopic pattern of cobblestone-like tiles with capillaries forming the borders of the individual tiles. As with punctation, the appearances of mosaic are determined by epithelial changes, which allow distinction between fine mosaic (minor change) and coarse mosaic (major change).

Fine Mosaic

Fine mosaic, like fine punctation, occurs in sharply demarcated areas in the plane of the superficial epithelium. The appearance of such an area before application of acetic acid can be nonspecific and can remind one of a relatively vascular TZ, which, however, is usually devoid of gland openings or cysts (Figs. 6.27 and 6.366.42). A distinct color change to gray-white occurs with acetic acid application, and the margins become sharp. The blood vessels become less conspicuous (Fig. 6.27b). The whole area remains in the same plane as before. The mosaic pattern is delineated by the fine network of pale red lines. Such an area may not display the mosaic pattern throughout its entirety; in places, the surface may be uniform and flat because the epithelium is not supported by elongated stromal papillae.

It can be difficult to classify mosaic as fine or coarse (Figs. 6.39 and 6.42). Intermediate forms are mostly caused by low-grade squamous intraepithelial lesion (LSIL), which may also produce various forms of punctation, depending on the degree of atypia and epithelial architecture.

Coarse Mosaic

Coarse mosaic is characterized by greater irregularity of the mosaic pattern. The network of fissures is more pronounced and intensely red. The furrows are more widely spaced, and the epithelial cobbles between them are bigger and more variable in shape than in the fine form (Figs. 6.386.41). The swelling from acetic acid makes the structures stand out (Fig. 6.41); the peak effect may take a minute to develop. The metamorphosis can be observed through the colposcope as the coarse structure of the mosaic and punctation gradually appears. In contrast, the effect of acetic acid on fine mosaic is immediate.

Gland openings and nabothian follicles are usually not found within areas of punctation or mosaic. Like leukoplakia, mosaic and punctation can also be found outside the TZ, in original squamous epithelium (Figs. 6.39, 6.43, and 6.44; see also Fig. 6.52). This is fundamental to the understanding of the morphogenesis of punctation and mosaic and epithelial atypia.

Punctation and mosaic occur in isolated fields (Figs. 6.39 and 6.436.45) and can coexist with other lesions (see Fig. 6.42; also see Fig. 7.20). In the latter case, the more peripherally located lesions usually represent lower-grade lesions (LSIL, CIN 1) or merely metaplastic epithelium, which was confirmed by topographic studies showing that mosaic and punctation occur more commonly outside than inside the TZ (84 vs. 16%). Histologically, mosaic and punctation outside the TZ corresponded to benign metaplastic epithelium in 70% and to CIN in only 30% of treated cases; within the TZ, the respective rates were 20 and 80%. Thus, mosaic and punctation within the TZ are more likely to represent CIN than are the same lesions outside the TZ.

6.2.4 Punctation

Punctation is a colposcopic finding caused by capillary loops near to and visible through the epithelial surface as dots in a stippled pattern. Usually, punctation is imprinted on a uniform surface that is undisturbed by either gland openings or nabothian follicles or by any other signs of a TZ. The degree of punctation depends on the type of underlying epithelial abnormality. The type of punctation, as well as of mosaic, is important at colposcopic evaluation. The colposcopist should be aware that similar colposcopic appearances can be due to either benign metaplastic epithelium or atypical epithelium, which differ only in arrangement and degree of expression.

Two types of punctation are of diagnostic importance: fine punctation (minor change) and coarse punctation (major change). There are good diagnostic criteria to distinguish between the two types, but it is not always possible to categorize a given case as one or the other. Such appearances should always be regarded with suspicion: biopsy should be carried out, or cytology should be repeated.

Fine Punctation

Fine punctation characteristically imparts delicate stippling to an otherwise circumscribed grayish white to reddish area (Fig. 6.45). When the epithelium is keratinized, the dots may appear white, but they are usually red and remain in the same plane as the surface epithelium, even after the application of acetic acid. The “dots” of fine punctation are close together (Fig. 6.46). Fine punctation is often combined with equally fine mosaic. Fine focal punctation may be due to inflammation, in which case the margins of the inflamed area appear indistinct after application of iodine (see Figs. 6.47 and 6.48b). Fine punctation can also be associated with LSIL (caused by human papillomavirus [HPV] infection). With the Schiller’s iodine test, the punctations become yellow to ocher, whereas the adjacent epithelium, as a result of the koilocytes, stains brown. This is known as iodine-positive punctation (Fig. 6.45b).

Coarse Punctation

Coarse punctation usually indicates HSIL. The petechiae are more pronounced, bigger, and widely separated (Figs. 6.44 and 6.496.51). In extreme cases, punctation resembles papillae (Fig. 6.52). With higher magnification, corkscrew capillaries can be seen in the papillae. After application of acetic acid, coarse punctation stands out from the plane of the surrounding surface epithelium (Fig. 6.49a, b). Coarse punctation may be combined with coarse mosaic. The two patterns may overlap, with intermingling of dots and fissures (Fig. 6.50).

Apr 16, 2018 | Posted by in OBSTETRICS | Comments Off on Colposcopic Findings
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