- A colposcope is a binocular microscope with magnification from 6 x to 40 x and a variable intensity light source to allow visualization of the lower genital tract. Box 1 lists the common terms in colposcopy.
- Patient preparation and procedure
a. The patient is placed in the lithotomy position, and the largest speculum that can comfortably be inserted is used to visualize the cervix and upper vagina.
b. Any excess mucus is gently removed with a cotton swab.
c. The entire cervix and transition zone must be clearly visualized. Inability to visualize the entire squamocolumnar junction results in an unsatisfactory colposcopy.
d. A green filter and high magnification may be used to allow improved visualization of the subepithelial angioarchitecture and to help identify abnormal vasculature.
e. Acetic acid (3% to 5%) is gently applied to the cervix with a cotton swab. Acetic acid reacts with nuclear protein, causing the tissue to swell, which prevents light from passing through it. Abnormal or dysplastic lesions have a large amount of nuclear protein; they therefore have a strong reaction to acetic acid and appear white (acetowhite).
BOX 1. Colposcopic Terminology
- Acetowhite epithelium (modification of epithelium after application of 5% acetic acid solution).
Grade 1: pale, pinkish appearance of underlying stroma still visible
Grade 2: whiter epithelium, increased thickness Grade 3: very opaque, irregular surface
- Punctation: set of vascular red dots disseminated in acetowhite lesion. Regularity and coarseness vary with severity of lesion.
- Mosaic: surface vessels arranged in a mosaic pattern. Density and irregularity of epithelial paving vary with grade of lesion.
- Hyperkeratosis: white epithelial lesion present before acetic acid application representing surface keratin.
- Abnormal vessels: abnormal forms of surface vessels described as commas, corkscrews, or spaghetti like. These vessels are signs of invasive disease.
From Alexander Meisels, Carol Morin: Cytopathology of the uterine cervix . American Society of Clinical Pathologists.
f. Once abnormal tissue has been identified, colposcopic biopsy can be performed using a cervical biopsy punch. If needed, multiple biopsies can be obtained. Each biopsy should be sent separately and labeled as to its location of origin. Any bleeding from the biopsy site can be controlled with Monsel’s solution or a silver nitrate stick.
g. An endocervical curettage (ECC) allows sampling of the endocervical canal above the squamocolumnar junction.
h. It is necessary to make a carefully diagrammed picture of the findings in the chart as well as to document plans for follow-up.