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Abnormal colposcopic findings
Most of abnormal colposcopic findings develop after the application of an aqueous 3-5% solution of Acetic acid. Impregnation of the cervix with acetic acid solution allows a clear visualization of the cervical epithelium. The mucus is dissolved and within one minute a strict contrast between the normal mucosa (remains unaltered) and any metaplasia or epithelial abnormality (becomes aceto-white) is fully developed, making possible their accurate direct visualization.
Another key element in the colposcopic examination is a Schiller's test. A solution of Iodine (Lugol's solution) is applied to the cervix to visualize any epithelial abnormalities. Following the iodine application, the normal mucosa will stain mahagony brown (iodine positive or Shiller's test negative), in contrast to epithelial abnormalities (metaplasia, CIN) that stain pale or remain completely unstained (iodine-negative or Shiller's test positive). It should be remembered that Schiller's test is not specific, i.e. cannot discriminate immature epithelium or benign changes from dysplasia.
Abnormal (atypical) colposcopic findings are the result of abnormal metaplasia, presented by abnormal colposocopic pictures.
General principles
Position of lesion inside or outside of the T-zone
T-zone: outer limit of T-zone can usually be recognized by the presence of gland openings and/or Nabothian cystis which are indicating where metaplasia has started. Immature metaplastic epithelium in T-zone which is undergoing the dynamic process of transformation from columnar to squamous epithelium, is susceptible to the development of atypical cellular changes. Abnormal colposcopic findings within this zone are generally considered more clinically significant.
Number of cervical quadrants the lesion covers:
This is not a rule, but there is an evidence that the larger the lesion is, the more severe epithelial abnormality is present. There is a direct relationship between the size of a lesion and the likelihood of invasion.
Types of abnormal findings
In colposcopy, it is essential to assess whether Transformation zone is normal or abnormal. Abnormal transformation zone is presented by variety of epithelial and vascular changes which can be seen as abnormal (atypical) colposcopic findings
Main types of abnormal colposcopic findings are:
• Acetowhite epithelium
• Mosaicism (mosaic)
• Punctation
• Leukoplakia
• Abnormal (atypical) vessels
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Acetowhite epithelium
Any lesion or abnormality in the uterine cervix and elsewhere in the lower genital system that appears white after the application of acetic acid is considered Aceto white (AW) epithelium. It is important to realize that acetowhite lesions comprise a wide variety of benign (metaplasia), premalignant (CIN) and malignant lesions and as such, acetowhite staining is not a specific diagnostic colposcopic pattern. In case of precancer/cancer, the intensity of the acetowhite staining correlates with the severity of the lesion.
Acetowhite epithelium can be caused by:
• HPV infection
• Immature squamous metaplasia
• Regenerative or reparative changes
• Congenital Transformation Zone
• Inflammation
• CIN
• Adenocarcinoma
• Invasive squamous carcinoma
Mosaicism or mosaic
Mosiac is colposcopic finding reflecting the islands of squamous epithelium, encircled by blood vessels in a basket-like arrangement. This is a characteristic colposcopic pattern where the underlying small blood vessels become visible on colposcopic examination in a pattern resembling a mosaic. Grading the mosaic as regular, irregular and coarse correlates with the severity of the lesion.
Punctation
Punctation is colposcopic finding reflecting the capillaries in the stromal papillae that penetrate the epithelium and are seen end-on. It is a characteristic colposcopic pattern where the underlying small blood vessels become visible on colposcopic examination as a punctuate lesion. Similarly to mosaic, grading the punctation as regular, irregular and coarse correlates with the severity of the lesion.
Causes of Punctation and Mosaic could be:
• Inflammation
• Rapid growth of metaplastic epithelium
• CIN
• Invasive squamous carcinoma
• Recurrence of cervical cancer
Leukoplakia
Leukoplakia is a distinct colposcopic pattern denoting a white patch. In pathology, leukoplakia is a clinical term, not a histopathological entity. In the cervix, leukoplakia is an area that becomes visible as white epithelium before the application of Acetic acid. On light microscopy such an epithelium usually presents with a thick layer of hyperkeratosis or parakeratosis. It also may cover a serious underlying pathology.
Leukoplakia can be caused by:
• HPV infection
• Keratinizing CIN
• Keratinizing cancer
• Chronic trauma
• Radiotherapy
• Immature metaplasia
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Abnormal (atypical) vessels
Atypical vessels are considered a key mark of invasion, However, some benign conditions may display atypical vascular pattern (diabetes, systemic diseases, vasculitis, chronic cervicitis). Each of these conditions requires thorough examination. Vessels should be graded atypical when their branching pattern is not tree-like (from larger to smaller), when they present with highly different shapes and show anastomosis. The frequency of atypical vessels usually increases in parallel with the severity of the lesion, being most common in invasive carcinoma.
In normal TZ blood vessels are usually not visible. Any visible vessels should alert the colposcopist for careful evaluation, whether their appearance is normal or abnormal. Normal vessels could be seen above Nabothian cysts. Abnormal vessels appear as irregular in shape with an abrupt and interrupted course and vessels appearing as commas, corkscrew capillaries or spaghetti-like forms.
Grading of abnormal findings
If any abnormality is seen, colposcopical report should include two important observations:
• Determination of the full extent of the abnormal epithelium.
• An estimation of the severity of the lesion.
The full extent of the abnormal epithelium within the Transformation zone must be seen before a satisfactory colposcopic opinion can be given. This means that the upper extent of the lesion must be seen. If this is not possible, then the presence of an early invasion cannot be excluded.
After the Acetic acid is applied, the squamocolumnar junction must be carefully inspected. If any abnormality is seen, the full extent of abnormal epithelium should be determined.
The estimation of the severity of the lesion is an important part of colposcopic examination. Ideally, colposcopic scoring should allow categorizing the colposcopic pattern as normal, abnormal but not clinically significant and abnormal clinically significant.
Cervical intraepithelial neoplasia (CIN) or Squamouls intraepithelial lesion (SIL) exhibits certain morphologic features that can be identified during a colposcopic exam. These features allow grading of colposcopic findings.
Grading of colposcopic findings takes into account:
• Vascular pattern
• Intercapillary distance
• Color tone and opacity
• Surface pattern
• Borders with normal tissue
Very simplified, the larger mosaic fields, punctations or intercapillary distance is, more severe is the lesion. Lesions which develop more intensive white color are histologically more severe than mildly white areas. Irregular surface is usually seen in more severe lesions, while low grade lesions have flat and smooth surface. Similarly, the lesion with borders which are sharp and linear, is more severe than the lesions which has irregular (geographical) borders, sometimes vaguely delineating it from the surrounding normal epithelium.
Based on severity and combination of these features, all atypical findings on the cervix can be divided to Grade 1 (G1) lesions, which indicates histologically less severe lesion (CIN1/L-SIL) and Grade 2 (G2) which is usually appearance of the higher grade lesion (CIN 2 and 3/H-SIL).
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Grade 1 (Minor grade findings)
Fine aceto-white epithelium
Fine mosaik
Fine punctation
Grade 2 (Major grade findings)
Dense aceto-white epithelium
Coarse mosaic
Coarse punctuation
Cuffed gland openings
Sharp border
However, the application of grading criteria such as color, surface pattern, iodine uptake, presence or absence of abnormal vessels and demarcation of an atypical transformation zone remains challenging, because only 20% of these atypical TZ contain CIN. There are a few more colposcopic signs highly correlated with CIN which can be useful in clinical practice especially for trainees in colposcopy.
Edge definition
An important aspect of colposcopic examination is looking at the margins of the lesion. It could give an important clue about possible severity of the lesion. While low-grade lesions usually have ill-defined margins, merging with the surrounding normal epithelium, imperceptibly, the edge definition comes sharper with increasing severity of the lesion. In high-grade lesions there may be more than one border within the abnormal TZ (inner borders), demarcating lesions with different severity from each other (i.e. low-grade CIN from high-grade CIN).
Inner border sign
Inner border sign (inner demarcation) is a rare colposcopic phenomenon but highly specific for CIN 2 or 3 in young women (usually younger than 35 years). It is a sharp aceto-white demarcation within a less opaque AW area. In 70% of women with inner border, CIN 2 or 3 was confirmed histologically. The sensitivity of the colposcopic sign inner border for detection of CIN 2 or 3 is 20%, and the specificity is 97%. There is no significant association between inner border and any high-risk HPV type.
Ridge sign
Ridge (ledge) sign refers to a thick epithelium growing in the SCJ, which exhibits opaque color and lack of iodine uptake. Colposcopic ridge sign is associated with CIN2 or CIN 3 in 64% to 74%, which gives high positive predictive value. Sensitivity and specificity of ridge sign for detection of CIN 2 or 3 is 33.1%; and 93.1% respectively8BO97UJ1. Women with ridge sign are significantly younger than women with no ridge sign. Contrary to the inner border sign, this sign is associated with the presence of HPV 16.
Rag sign
Rag sign is an opaque acetowhite area at the SCJ, mechanically abraded during either collection of the smear for cytology or HPV testing and/or applying acetic acid or Lugol's solution. In rag sign, part of the epithelium is sloughed off in a rag.
Rapid appearance of acetowhitening
The time needed for a white color to appear, the shorter it is (fast appearance), more severe the lesion is.
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