Features that are useful to distinguish and characterize any lesion are gross appearance, acetowhitening, vascular changes, internal and external boundaries, and iodine uptake. Low-grade lesions exhibit typical changes in most or all of these characteristics. Gross visual inspection of the cervix is an essential first step in evaluation.
The vast majority of low-grade lesions are flat with a smooth surface. The exceptions are acuminate and flat condylomas. Condylomas may arise within the transformation zone or as skip lesions within the mature squamous epithelium. Papillary spike-like projections are macroscopically apparent on the surface of acuminate warts and are visible as regular projections (asperites) on the surface of flat condylomas with colposcopic magnification.
Some low-grade lesions may appear white prior to the application of acetic acid and are termed leukoplakia. The majority of these lesions represent benign hyperkeratosis or occasionally low-grade human papillomavirus lesions, but on rare occasions may mask an underlying keratinizing carcinoma.
The degree of acetowhitening is variable in low-grade lesions. The acetowhitening of low-grade lesions is typically faint. The acetowhite change may be slow to develop, transient, and quick to disappear. It also may be a bright white, which is characteristic of condyloma.
Low-grade lesions are characterized by a smooth surface with indistinct borders or irregular, “feathered” or “geographic” outer borders. Internal borders within the lesion are not present. Satellite acetowhite lesions arising within the mature squamous epithelium outside of the transformation zone are almost always low-grade.
Lugol’s iodine application is negative in immature squamous metaplasia, atrophy, and cervical intraepithelial neoplasia due to a lack of glycogenation of the squamous epithelium. A speckled or tortoise shell appearance, indicating partial iodine uptake, is associated with slight acetowhite change may be immature metaplasia or low-grade intraepithelial neoplasia. Complete iodine negativity is more suggestive of high-grade neoplasia.
Low-grade lesions are either featureless or have fine mosaicism or punctation. The vascular change has a regular pattern with equal intercapillary distances. If the intercapillary distance is markedly increased and irregular it is more likely a high-grade lesion. As a general rule, atypical vessels such as nonarborizing comma or hairpin vessels are not present in low-grade lesions. A notable exception is the prominent vascularity that may be present with inflammatory reparative lesions and the central capillary loops of condyloma.
It is a general rule that the most severe area of the lesion is the most proximal to the squamocolumnar junction. The difficulty lies in learning to distinguish low-grade lesions from immature metaplasia which also exhibits acetowhitening and fine vascular patterns. With experience, recognition of benign variants like immature metaplasia, cervicitis, atrophy, and pregnancy changes that mimic neoplasia can be accomplished. In fact, the distinction is often based on the degree of subtle colposcopic findings and biopsy is often necessary to confirm the diagnosis. Due to the variability of the colposcopic appearance of low-grade lesions, the accuracy and reproducibility of diagnosis is less than that of higher grade lesions.
References
- Walker P, Dexeus S, DePalo G, et al. International terminology of colposcopy: An updated report from the international federation for cervical pathology and colposcopy. Obstet Gynecol 2003;101(1): 175-7.
- Apgar BS, Spitzer M, Brotzman GL (eds):. Colposcopy Principles and Practice. An Integrated Textbook and Atlas. Philadelphia, PA, W.B. Saunders Company, 2002.
- Burghardt E, Pickel H, Girardi F: Colposcopy-Cervical Pathology: Textbook and Atlas. 3rd ed. New York, Thieme, 1998.
- Modern Colposcopy Textbook and Atlas, Second Edition. American Society for Colposcopy and Cervical Pathology. Kendall-Hunt Publishing Co., Dubuque, 2004. Chapters 3, 18.
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