Colposcopy and Treatment of Cervical Intraepithelial Neoplasia - RHO

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Chapter 1 In premenopausal women, the transformation zone is fully located on the ectocervix. After menopause through old age, the cervix shrinks with the decreasing levels of estrogen. Consequently, the transformation zone may move partially, and later fully, into the cervical canal. The transformation zone may be described as normal when it is composed of immature and/or mature squamous metaplasia along with intervening areas or islands of columnar epithelium, with no signs of cervical carcinogenesis (Figure 1.14a). It is termed an abnormal or atypical transformation zone (ATZ) when evidence of cervical carcinogenesis such as dysplastic change is observed in the transformation zone (Figure 1.14b). Identifying the transformation zone is of great importance in colposcopy, as almost all manifestations of cervical carcinogenesis occur in this zone. Congenital transformation zone During early embryonic life, the cuboidal epithelium of the vaginal tube is replaced by the squamous epithelium, which begins at the caudal end of the dorsal urogenital sinus. This process is completed well before birth and the entire length of vagina and the ectocervix is meant to be covered by squamous epithelium. This process proceeds very rapidly along the lateral walls, and later in the anterior and posterior vaginal walls. If the epithelialization proceeds normally, the original squamocolumnar junction will be located at the external os at birth. On the other hand, if this process is arrested for some reason or incomplete, the original squamocolumnar junction will be located distal to the external os or may rarely be located on the vaginal walls, particularly involving the anterior and posterior fornices. The cuboidal epithelium remaining here will undergo squamous metaplasia. This late conversion to squamous epithelium in the anterior and posterior vaginal walls, as well as the ectocervix, results in the formation of the congenital transformation zone. Thus, it is a variant of intrauterine squamous metaplasia, in which differentiation of the squamous epithelium is not fully completed due to an interference with normal maturation. Excessive maturation is seen on the surface (as evidenced by keratinization) with delayed, incomplete maturation in deeper layers. Clinically, it may be seen as an extensive whitish-grey, hyperkeratotic area extending from the anterior and posterior lips of the cervix to the vaginal fornices. Gradual maturation of the epithelium may occur over several years. This type of transformation zone is seen in less than 5 % of women and is a variant of the normal transformation zone. 12
Chapter 2 An introduction to cervical intraepithelial neoplasia (CIN) • Invasive squamous cell cervical cancers are preceded by a long phase of preinvasive disease, collectively referred to as cervical intraepithelial neoplasia (CIN). • CIN may be categorized into grades 1, 2 and 3 depending upon the proportion of the thickness of the epithelium showing mature and differentiated cells. • More severe grades of CIN (2 and 3) reveal a greater proportion of the thickness of the epithelium composed of undifferentiated cells. • Persistent infection with one or more of the oncogenic subtypes of human papillomaviruses (HPV) is a necessary cause for cervical neoplasia. • Most cervical abnormalities caused by HPV infection are unlikely to progress to high-grade CIN or cervical cancer. • Most low-grade CIN regress within relatively short periods or do not progress to high-grade lesions. • High-grade CIN carries a much higher probability of progressing to invasive cancer. • The precursor lesion arising from the columnar epithelium is referred to as adenocarcinoma in situ (AIS). AIS may be associated with CIN in one-to two-thirds of cases. Invasive cervical cancers are usually preceded by a long phase of preinvasive disease. This is characterized microscopically as a spectrum of events progressing from cellular atypia to various grades of dysplasia or cervical intraepithelial neoplasia (CIN) before progression to invasive carcinoma. A good knowledge of the etiology, pathophysiology and natural history of CIN provides a strong basis both for visual testing and for colposcopic diagnosis and understanding the principles of treatment of these lesions. This chapter describes the evolution of the classification systems of cervical squamous cell cancer precursors, the cytological and histological basis of their diagnosis, as well as their natural history in terms of regression, persistence and progression rates. It also describes the precancerous lesions arising in the cervical columnar epithelium, commonly referred to as glandular lesions. The concept of cervical cancer precursors dates back to the late nineteenth century, when areas of noninvasive atypical epithelial changes were recognized in tissue specimens adjacent to invasive cancers (William, 1888). The term carcinoma in situ (CIS) was introduced in 1932 to denote those lesions in which the undifferentiated carcinomatous cells involved the full thickness of the epithelium, without disruption of the basement membrane (Broders, 1932). The association between CIS and invasive cervical cancer was subsequently reported. The term dysplasia was introduced in the late 1950s to designate the cervical epithelial atypia that is intermediate between the normal epithelium and CIS (Reagan et al., 1953). Dysplasia was further categorized into three groups – mild, moderate and severe – depending on the degree of involvement of the epithelial thickness by the 13
Page 1 and 2: Colposcopy and Treatment of Cervica
Page 3 and 4: INTERNATIONAL AGENCY FOR RESEARCH O
Page 5 and 6: Published by the International Agen
Page 7 and 8: Contents 11 Management that provide
Page 9 and 10: Acknowledgements The authors gratef
Page 11 and 12: Preface Health care providers have
Page 13 and 14: Chapter 1 An introduction to the an
Page 15 and 16: An introduction to the anatomy of t
Page 23: An introduction to the anatomy of t
Page 27 and 28: An introduction to cervical intraep
Page 33 and 34: Chapter 3 An introduction to invasi
Page 35 and 36: An introduction to invasive cancer
Page 41 and 42: Chapter 4 Table 4.1: Indications fo
Page 43 and 44: Chapter 4 FIGURE 4.2: Colposcope wi
Page 45 and 46: Chapter 4 FIGURE 4.6: Endocervical
Page 47 and 48: Chapter 4 Table 4.2: Preneoplastic
Page 49 and 50: Chapter 5 between the two ocular le
Page 51 and 52: Chapter 5 Obtain specimens for labo
Page 53 and 54: Chapter 5 FIGURE 5.2: Biopsy techni
Page 55 and 56: Chapter 5 tissue tends to mimic inv
Page 57 and 58: Chapter 6 invasive carcinoma. Even
Page 59 and 60: Chapter 6 ages (Figures 1.7d, 1.7e,
Page 61 and 62: Chapter 6 FIGURE 6.7: The colour ch
Page 63 and 64: Chapter 6 Crypt openings Immature s
Page 65 and 66: Chapter 6 a FIGURE 6.17: An area of
Page 67 and 68: Chapter 7 The colposcopic diagnosis
Page 69 and 70: Chapter 7 appears as individual sma
Page 71 and 72: Chapter 7 acid stain is correlated
Page 73 and 74: Chapter 7 FIGURE 7.15: Moderately d
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Chapter 7 FIGURE 7.23: A dense acet
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Chapter 7 FIGURE 7.30: Mustard yell
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Chapter 7 We recommend that the stu
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Chapter 8 highlights this responsib
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Chapter 8 Appearance before applica
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Chapter 8 diagnosis of AIS and aden
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Chapter 8 a ↑ FIGURE 8.10: Adenoc
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Chapter 9 Inflammatory lesions of t
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Inflammatory lesions of the uterine
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Inflammatory lesions of the uterine
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Chapter 10 Table 10.1: Common sourc
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Chapter 10 Table 10.2 (cont.): A su
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Chapter 11 FIGURE 11.1: Flow chart
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Chapter 11 treatment policies for p
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Chapter 11 Vaginal delivery can be
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Chapter 12 involvement increases wi
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Chapter 12 Table 12.1: Eligibility
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Chapter 12 a b c d e f FIGURE 12.6:
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Chapter 12 during the follow-up in
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Chapter 13 (2) (1) FIGURE 13.2: Ele
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Chapter 13 (1) (2) (3) (4) (5) (8)
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Chapter 13 Once the specimen has be
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Chapter 13 in the endocervical cana
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Chapter 14 Decontamination, cleanin
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Decontamination, cleaning, high-lev
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References Herrero, R. (1997) Preva
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Further reading Suggestions on furt
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Appendix Leukoplakia Condylom
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Appendix regardless of your pregnan
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Appendix Monsel’s paste Ingredien
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Appendix 5 The modified Reid colpos
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Index Acetowhitening . . . . . . .
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