The Papanicolaou smear (Pap smear) is a commonly used screening test for dysplasia and cancer of the uterine cervix.
Colposcopy is the diagnostic test to evaluate patients with an abnormal cervical cytological smear or abnormal-appearing cervix. It entails the use of a field microscope to examine the cervix after acetic acid and Lougal's iodine are applied to temporarily stain the cervix. The cervix and vagina are examined under magnification, and all abnormal areas are identified.
If the colposcopy is satisfactory (the entire transformation zone is examined and the extent of all lesions is seen), directed biopsies of all lesions and especially the most severe lesions are performed. This leads to a tissue diagnosis of the disease present.
Indications for colposcopy include:
(1) Papanicolaou smear consistent with HPV infection, dysplasia, or cancer (LSIL or HSIL).
(2) Papanicolaou smear with ASCUS favor dysplasia or repeated ASCUS.
(3) Papanicolaou smear with repeated unexplained inflammation.
(4) Abnormal-appearing cervix.
(5) Patients with a history of intrauterine diethylstilbestrol (DES) exposure.
Lesions that are more likely to be missed or under-read by colposcopic examination include endocervical lesions, extensive lesions that are difficult to sample, and necrotic lesions.
NORMAL COLPOSCOPIC FINDINGS
Original Squamous Epithelium.The original squamous epithelium is a featureless, smooth, pink epithelium. There are no features suggesting columnar epithelium such as gland openings or Nabothian cysts. Epithelium is considered "always" squamous and was not transformed from columnar to squamous.
Columnar Epithelium.
The columnar epithelium is a single-cell layer, mucous producing, tall epithelium that extends between the endometrium and the squamous epithelium. Columnar epithelium appears red and irregular with stromal papillae and clefts. With acetic acid application and magnification, columnar epithelium has a grape-like or "sea-anemone" appearance. It is found in the endocervix, surrounding the cervical OS, or (rarely) extending into the vagina.
Squamocolumnar Junction(SCJ).
Generally, a clinically visible line seen on the ectocervix or within the distal canal (e.g., post-cryotherapy), which demarcates endocervical tissue from squamous (or squamous metaplastic tissue). This is an anatomical feature.
Squamous Metaplasia.
The physiologic, normal process whereby columnar epithelium matures into squamous epithelium. Squamous metaplasia typically occupies part of the transformation zone. At the squamocolumnar junction it appears as a "ghost white" or white-blue film with the application of acetic acid. It is usually sharply demarcated toward the cervical os and has very diffuse borders peripherally.
Transformation Zone (Tz).
The geographic area between the original squamous epithelium (before puberty) and the current squamocolumnar junction is the Transformation Zone. It may contain gland openings, Nabothian cysts, and islands of columnar epithelium surrounded by metaplastic squamous epithelium.
ABNORMAL COLPOSCOPIC FINDINGS
Atypical Transformation Zone.A transformation zone with findings suggesting cervical dysplasia or neoplasia. (Terms also can be applied to findings outside the transformation zone, i.e., vagina)
Acetowhite (AW). A transient, white-appearing epithelium following the application of acetic acid. Areas of acetowhiteness correlate with higher nuclear density.
Punctation. A stippled appearance to capillaries seen end-on, often found within acetowhite area appearing as fine to coarse red dots.
Mosaicism. An abnormal pattern of small blood vessels suggesting a confluence of "tile" or "chickenwire" reddish borders.
Leukoplakia (hyperkeratosis). Typically an elevated, white plaque seen prior to the application of acetic acid.
Abnormal blood vessels. Atypical, irregular vessels with abrupt courses and patterns, often appearing as commas, corkscrews, or spaghetti. No definite pattern is recognized, as with punctation or mosaicism.
Suspect invasive cancer. Complex pattern consisting of roughened, irregular cervical epithelium, typically with abundant irregular vessel patterns. Blood vessels take bizzare forms, which appear as commas, hair pins, spaghetti, or long, dilated, unbranching vessels with irregular diameters.
OTHER COLPOSCOPIC FINDINGS
Vaginocervicitis. Cervicitis may cause abnormal Pap smears and make colposcopic assessment more difficult. Many authorities recommend treatment before biopsy when a STD is strongly suspected.
Traumatic erosion.Traumatic erosions are most commonly caused by speculum insertion and over vigerous Pap smears but can also result from such irritants as tampons, diaphrams, and intercourse.
Atrophic epithelium.Atrophic vaginal or cervical epithelium may also cause abnormal Papancolaou smears. Colposcopists will often prescribe estrogen for 2 to 4 weeks before a colposcopy in order to "normalize" the epithelium before the examination. This is generally felt to be safe even if dysplasia or cancer is present because the duration of therapy is short and these lesions do not express any more estrogen receptors than a normal cervix. (3)
Nabothian cysts.Nabothian cysts are normal. They are areas of mucus producing epithelium that are "roofed over" with squamous epitelium. They do not require any treatment. They provide markers for the transformation zone since they are in squamous areas but are remnants of columnar epithelium.
UNSATISFACTORY COLPOSCOPY
The practice of colposcopy assumes that the worst parts of the worst lesions will be biopsied. This requires that the borders of all lesions be entirely seen. The entire transformation zone, including all the squamocolumnar junction, also must be visualized in order for a colposcopy to be considered adequate. Unsatisfactory colposcopy with cytologic evidence of dysplasia or extensive canal disease frequently requires cervical cone biopsy for work-up. If the entire squamocolumnar junction or the limits of all lesions cannot be completely visualized, a diagnostic conization with a cold knife cone, laser cone, or LEEP conization is necessary.
Grading lesions
Carefully note the shape, position, and findings of all lesions in order to draw a picture of the lesions and biopsy sites.
Classically, the following parameters are used to grade severity of lesions:
Less Severe > > More Severe
1) Mild acetowhite epithelium > Intensely acetowhite
2) No blood vessel pattern > Punctation > Mosaic
3) Diffuse vague borders > Sharp demarcated borders
4) Follows normal contours of the cervix > "humped up"
5) Normal iodine reaction (dark) > Iodine-negative epithelium (yellow)
6) Leukoplakia - usually a very good (condylomata) or a very bad sign (SCC)
Atypical vessels usually indicate severe dysplasia or cancer. Acetowhite areas that have sharp geographic borders and a dimension of thickness or roughness are likely to be histologically more severe. Furthermore, all other things being equal, the presence of vessel atypia in any lesion implies more severe dysplasia.
A more formal system of assessing the severity of cervical dysplasia is the Reid Colposcopic Index. It uses a point system to grade the lesion margins, color, blood vessel pattern, and strong iodine staining characteristics. It is more objective but not universally accepted as better to classic subjective grading.
