The Colposcope and the Colposcopic Examination

Chapter 3


The Colposcope and the Colposcopic Examination




3 The Colposcope and the Colposcopic Examination


Modern colposcopes permit magnification between ×6 and ×40. Magnification ×10 is most suitable for routine use. Higher magnifications reveal minor features but are not necessary for accurate diagnosis. The colposcope can be equipped with a green filter to filter out red and thereby enhance the vascular appearance of the vessels by making them look darker.


A colposcope can be mounted in different ways. For routine use, a swivel arm attached to the gynecologic examination chair is very practical (Fig. 3.1). The scope can be easily adjusted by hand, both vertically and horizontally. A colposcope on a mobile stand is independent of the examination table (Fig. 3.2). It can be fitted with a swivel arm and, with the wheels locked, can be used in the same way as a scope mounted on the examination table. Colposcopes mounted on the wall or ceiling are easy to handle because of their mobility. The head of the colposcope can be tilted up, down, and sideways. There is usually no need for the fine adjustment, as a sharp focus can be achieved just as easily by positioning the scope at the working distance of 20 to 24 cm.


Photographic and video equipment are important accessories. For teaching, a camera and video equipment are mandatory. Video colposcopy can improve patient satisfaction. New technologies are likely to improve the colposcopic detection of precancerous lesions.




3.1 Colposcopic Instruments


Colposcopy requires few instruments. In addition to the colposcope, one needs a duckbill speculum or Breisky-type retractors, anatomic forceps and swabs, dilute acetic acid and iodine, and biopsy instruments (Fig. 3.3). Some colposcopists use an endocervical speculum to improve access to the cervical canal (Fig. 3.3).


3.1.1 Specula


A duckbill speculum (Fig. 3.3) usually provides adequate exposure of the cervix and can be manipulated by the examiner without assistance. Duckbill specula are available in various sizes. On occasion, vaginal (Breisky) retractors (Fig. 3.3) are helpful, particularly to evaluate lesions involving the fornix and vagina. A disadvantage of the Breisky speculum is that the anterior blade needs to be held by an assistant.


3.1.2 Forceps


Anatomic forceps 20 cm or longer are needed to handle swabs (Fig. 3.3). They are more practical than tenacula. Sometimes forceps can be used to improve access to the cervical canal, for example, to evaluate the squamocolumnar junction (SCJ) and define the type of transformation zone.


3.1.3 Containers


Swabs are placed in a bowl from which they can be easily retrieved with forceps. For the acetic acid test (Fig. 3.3), swabs are soaked in 3% acetic acid and handled with forceps. Iodine (Lugol’s solution) is put into test tubes, which are placed in a rack. Tampons, which can be removed by the patient later (Fig. 3.12), are available.


3.2 Biopsy Instruments


There are several types of biopsy instruments (Fig. 3.3). They are usually scissor-shaped and between 20 and 25 cm in length. Sharp curets of various sizes are needed for scraping the endocervical canal and to obtain material from clinically invasive cancers. To curet a narrow endocervical canal, instruments with fine, sharp grooves are more practical than spoon-shaped ones.



3.2.1 Tenacula


To prevent slipping of the biopsy punch and obtain an accurately directed biopsy, fixation of the cervix is sometimes helpful. This can be done easily and painlessly with a single-toothed tenaculum (Fig. 3.3). Cervical polyps can be avulsed with polyp forceps (Fig. 3.3).


3.2.2 Chrobak’s Probe


Chrobak’s probe (Fig. 3.4) is a thin steel sound with a bulbous head that is useful to distinguish between carcinomas and papillomas or flat ectocervical ulcers. When investigating normal tissue or benign tumors, the probe encounters an elastic resistance; in contrast, malignant tissue feels soft, like warm butter.


3.3 The Colposcopic Examination


The colposcopic examination begins with an explanation for the patient. Video systems make this easier. The vulva and perianal region are inspected. An appropriate duckbill speculum is inserted; lubrication of the speculum can be helpful. Secretions and signs of inflammation in the vagina are noted, if present. The cervix is visualized and dry swabbed to remove mucous. The cervix, particularly the vessels, is inspected colposcopically in the native state. A smear for cervical cytology (Pap smear) is obtained with an Ayre’s spatula, cervical brush, or cotton-tipped swab. If indicated, material for human papillomavirus (HPV) testing is obtained with an appropriate brush. If liquid-based cytology is used, only one sample of material is obtained with an appropriate brush and transferred to the container; cytology, HPV testing, and other molecular tests are done from the liquid suspension.


On occasion, the cervix can be difficult to expose adequately. This can be the case in very obese women, patients with a narrow vagina or vaginal stenosis, or patients with pelvic tumors or a fibroid uterus distorting the anatomy. In these (rare) cases, we obtain a smear without visualizing the cervix proper.


The acetic acid test and the iodine test (Schiller’s test), which we consider integral parts of the colposcopic examination, are next. At the end of the colposcopic examination, we make a decision as to whether and where to biopsy. It is our practice to biopsy a major lesion noted at colposcopy without awaiting the results of cytology or HPV testing.


3.3.1 Application of Acetic Acid


Application of 3% acetic acid plays a decisive role in colposcopic diagnostics. No colposcopic examination is complete without it.



After removing vaginal secretions with dry swabs, the cervical epithelium is often still masked by a film of mucus, especially in the presence of ectopy. Cleansing the cervix of mucous with acetic acid enhances the colposcopic features. This applies especially to the grapelike structure of columnar epithelium in ectopy. However, all epithelial lesions become more distinct with acetic acid, the color changes are accentuated, and the various structures become more easily distinguishable from one another (Fig. 3.5). Care should be taken to apply the swab with acetic acid for 10 seconds or longer; if there is any question, application of acetic acid should be repeated.


Ectopy shows a dramatic change of color after application of acetic acid. The intense dark red ectopic columnar epithelium becomes paler and displays shades of pink to white. At the same time, the grapelike structures become more pronounced because of swelling and enlargement of the villi (Fig. 3.6).


Similar changes can be seen in altered epithelia. The epithelial swelling caused by acetic acid turns atypical epithelium white and accentuates its surface contour (Fig. 3.7). The patterns of mosaic and punctation also become more distinct, and the red partitions and fine petechiae stand out against the white epithelium (Fig. 3.8).


Because the effect on pathologic epithelium is not as rapid as on ectopic columnar epithelium, the white epithelium that appears after application of acetic acid should not be confused with leukoplakia.


3.3.2 Schiller’s (Iodine) Test


Application of iodine quickly produces intense staining of glycogen-containing epithelium (Fig. 3.1). This makes it an important diagnostic aid for assessing colposcopic findings. Lugol’s iodine solution was first used in clinical diagnosis by Walter Schiller in 1929, hence the term Schiller’s test. While some colposcopists do not use iodine, we find it very useful for the evaluation of colposcopic morphology. We pay particular attention to how acetowhite epithelium reacts with the Lugol’s solution (Table 3.1).






The 1% iodine solution consists of 2 g iodine and 4 g potassium iodide dissolved in 200 mL distilled water.


The Schiller’s test depends on the interaction between iodine and glycogen. The glycogen-containing vaginal epithelium of women of reproductive age quickly takes up iodine to produce an intense mahogany brown. Glycogen-free epithelium stains yellow (not brown) with iodine (Fig. 3.9). Such an area is referred to as iodine-yellow (sometimes—and in our opinion incorrectly—to as iodine negative).


Iodine solution stains normal glycogen-containing squamous epithelium uniformly deep brown. Such epithelium is found during the reproductive period and reflects the influence of estrogens (Fig. 3.10).


Columnar epithelium does not stain with iodine (Fig. 3.10) nor does thin regenerating epithelium, seen during the early stages of squamous metaplasia (Fig. 3.11). Failure to stain with iodine is useful to assess inflammatory lesions, which, because of their increased vascularity and capillary dilatation, can mimic punctation. Inflammation is associated with indistinct margins and failure to react strongly with iodine (Fig. 3.12).


Dysplastic epithelium stains with iodine as described later, even when still thin. This is an important difference between the normal transformation zone and the acetowhite epithelium. A colposcopic lesion, as well as the whole length of the vagina, can display all shades between tan and the chestnut brown of normal squamous epithelium (Fig. 3.13).


The vagina can have a stippled brown appearance, especially after menopause, when the effect of estrogen wanes. The postmenopausal cervix and vagina stain light brown to yellow (Fig. 3.14; see also Fig. 6.7).


Table 3.1 Normal and abnormal reactions with iodine





































Designation


Staining


Underlying histology


Iodine positive


Deep brown (mahogany)


Mature glycogen-containing squamous epithelium


Iodine negative


None


Columnar epithelium Immature metaplastic epithelium Inflammation


Weak staining


Lighter shades of brown


Waning estrogen effect (menopause) Transformation zone during metaplasia


Iodine-yellow


Characteristic canary yellow to ocher


HSIL (CIN 2, CIN 3)


Nonsuspicious iodine-yellow area


Yellow


Metaplastic squamous epithelium LSIL (CIN 1)


Iodine positive mosaic or punctation


Brown, brownish, speckled brown


Condylomatous colpitis, condylomatous lesions


Abbreviations: CIN, cervical intraepithelial neoplasia; HSIL, high-grade squamous intraepithelial lesion; LSIL, low-grade squamous intraepithelial lesion.


Apr 16, 2018 | Posted by in OBSTETRICS | Comments Off on The Colposcope and the Colposcopic Examination
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