Introduction to Colposcopy


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. Click here for a Transformation Zone picture.

Indications for colposcopy include: (1)

  1. Papanicolaou smear consistent with dysplasia or cancer.
  2. Papanicolaou smear with evidence of HPV infection (don't assume it is only HPV).
  3. Papanicolaou smear with ASCUS or repeated ASCUS.
  4. Papanicolaou smear with repeated inflammation.
  5. Abnormal-appearing cervix.
  6. 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. (2)


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.


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.



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.


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. Inadequate 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. (4)

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: (5)

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. (5, 6)

A more formal system of assessing the severity of cervical dysplasia is the Reid Colposcopic Index. (5, 6) 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.

ECC and Biopsy

Apply topical 20% benzocaine (Hurricane Solution) to decrease pain. It is effective in 30 to 45 seconds. Perform an Endocervical Curettage (ECC) before taking any biopsies unless the resultant blood would make biopsy difficult. Use a Kevourkian curette (preferably without a basket) and scrape the canal, 360 degrees, twice. The sample appears as a coagulum of mucus, blood, and small tissue fragments. Use ring forceps or a cytobrush to gently retrieve the sample. Submit on paper and label "ECC." Do not do an ECC on pregnant patients.

Next, perform cervical biopsy. Biopsy posterior areas first to avoid blood dripping over future biopsy sites. The cervix can be manipulated with a Q-tip or hook if necessary to provide an adequate angle for biopsy.

Align the forcep radially from the os so that the fixed jaw of the forcep is placed on the most posterior part of the site. The jaws should be centered over the area to be biopsied. Biopsies should be approximately 3 mm deep and should include all areas with vessel atypism. It is not necessary to include normal margins with biopsy samples. If bleeding is profuse from a particular site and more biopsies are needed, apply a Q-tip to the area and proceed with the next biopsy.

Do not apply Monsel's solution until all biopsies are completed. Apply pressure first and Monsel's solution if needed to bleeding sites. The Monsel's should be as thick as toothpaste to be most effective. Swab out the excess Monsel+blood debris, that appears as a nasty black substance which eventually will pass and may cause alarm (and potential late night phone calls).


Follow-up is usually in 2 to 3 weeks to discuss pathology results and plan treatment if necessary. With the high regression rate of CIN 1, patients can be followed with serial colposcopy if adequate follow-up can be assured. (4) CIN 2 and 3 are usually treated.

Be concerned if a significant discrepancy is found between the colposcopic impression, Pap cytology, and biopsy histology. Be especially concerned if the biopsy reports are significantly less than Pap cytology. For instance, a Pap smear indicating carcinoma-in-situ and biopsies of only mild dysplasia could signify that the worst area was not biopsied. In general, a difference of one grade (i.e., Pap = CIN 2 and biopsy = CIN 3) is common and acceptable. Do not freeze any cervix until you have adequately and sufficiently explained any discrepancy between histology and cytology. If the discrepancy cannot be explained, conization is indicated. (2) Repeating colposcopy is forgivable, even in the hands of the best. Freezing invasive cancer is not.

Cone biopsy (cold cone, laser, or LEEP cone) is indicated if the endocervical curettage sample reveals dysplasia. It is a sin to freeze the cervix with disease in the canal. "Positive" ECC's are sometimes a result of contamination with dysplastic lesions at the verge of the os. Nonetheless, do not assume this!

Know your limitations! Never be afraid to call in help with an uncertain lesion or result.


Candidates for outpatient cervical cryotherapy are patients with smaller lesions that do not enter the cervical os. Large lesions (over 1" in diameter, more than 1/2" from the os, or involving more than two cervical quadrants), even if they are only mild dysplasia, may be more appropriate loop or laser therapy candidates than a small focal severe dysplasia that may respond to ambulatory cryotherapy very well. (4) Large lesions, lesions that enter the cervical os, or CIN 3 / CIS lesions are most appropiately treated with LEEP or laser therapy.

Follow-up after treatment is in 4- to 6-month intervals for 2 years, with colposcopy or colposcopy intersperced with Pap smears. Recurrence is most common in the first 2 years after therapy. Recurrences are most common in the os and on the outside margins. A positive margin on a LEEP specimin requires colposcopic follow-up.


1. Newkirk GR, Granath BD. Teaching colposcopy and androscopy in family practice residencies. J Fam Pract 1990; 31:171-8.

2. McCord ML, Stovall TG, Summitt RL, Ling FW. Discrepancy of cervical cytology and colposcopic biopsy: Is cervical conization necessary? Obstet Gynecol 1991; 77:715-9.

3. Sadan O, Frohlich RP, Driscoll JA, Apostoleris A, Savage N, Zakust H. Is it safe to prescribe hormonal contraception and replacement therapy to patients with premalignant and malignant uterine cervices? Gynec Oncol 1986; 34:159-63.

4. Brotzman GL, Apgar BS. Cervical intraepithelial neoplasia: Current management options. J Fam Pract 1994; 39:271-8.

5. Reid R, Campion MJ. HPV-associated lesions of the cervix: Biology and colposcopic features. Clin Obstet Gynecol 1989; 32:157-79.

6. Reid R, Scalzi P. Genital warts and cervical cancer. VII. An improved colposcopic index for differentiating benign papillomaviral infections from high-grade cervical intraepithelial neoplasia. Am J Obstet Gynecol 1985; 153:611-8.

7. Stafl A, Wilbanks GD. An international terminology of colposcopy: Report of the nomenclature committee of the International Federation of Cervical Pathology and Colposcopy. Obstet Gynecol 1991; 77:313-4.