Colposcopy involves the use of a colposcope and chemical solutions to optically magnify the exposed vagina and cervix by 5 to 40 times. It allows for the observation of vascular patterns and epithelial structures, identification of abnormal areas, and targeted biopsy of suspicious lesions. Combined with cytology results and HPV testing, colposcopy provides imaging guidance for clinical management. Additionally, colposcopy is also employed in the evaluation of lesions on the vulva, perineum, and perianal regions.
Indications
While colposcopy may cause some discomfort and its interpretation is subjective, it cannot be used as a cervical cancer screening tool. The indications for colposcopy are as follows:
- Positive HPV types 16 or 18.
- Persistent high-risk HPV positivity.
- High-risk HPV positivity accompanied by ASC-US (Atypical Squamous Cells of Undetermined Significance) on cervical cytology.
- Cervical cytology results of LSIL (Low-Grade Squamous Intraepithelial Lesion) or higher.
- Visible cervical ulcers, masses, or suspected cervical cancer.
- Unexplained lower genital tract bleeding or abnormal vaginal discharge.
- Suspicious vulvar or vaginal lesions.
- Pre-conization evaluation to determine the extent of resection and preoperative assessment of cervical cancer lesion involvement.
- Follow-up after treatment of cervical, vaginal, or vulvar lesions.
For cytology findings of ASC-H (Atypical Squamous Cells–Cannot Exclude High-Grade) or glandular cell abnormalities, HPV types 16 or 18 positivity, type III transformation zones, lesions extending into the cervical canal, or colposcopic suspicion of high-grade lesions, endocervical curettage is recommended.
Contraindications
There are no absolute contraindications; relative contraindications include acute lower genital tract infections and menstruation. Activities such as vaginal douching, use of vaginal medications, and sexual intercourse within 24 hours prior to colposcopy are discouraged.
During pregnancy, endocervical curettage is prohibited.
Examination Procedure
Evaluation and Documentation
The indication for colposcopy is assessed, and prior histories such as cytology and HPV testing results, treatments, contraception methods, pregnancy status, menopausal status, hysterectomy status, smoking history, HIV status, and HPV vaccination history are recorded. Informed consent is obtained from the patient.
Observation of the Cervix
The cervix is sufficiently exposed with minimal patient discomfort, and cervical mucus is removed using saline-moistened cotton swabs. The cervix is observed in its entirety under magnification of 7 to 8 times, which allows identification of leukoplakia and abnormal vasculature. A green filter lens is used with magnification of 10 to 15 times for further assessment of vascular changes.
Acetic Acid Test
This is considered a definitive test. A cotton swab soaked with 5% acetic acid is applied to the upper vaginal wall and cervical surface, allowing sufficient action time (at least 1 minute). The cervix and upper vaginal wall are observed under magnification, with further exploration of the mid and lower vaginal walls if abnormalities are detected. Following acetic acid application, nuclear proteins of epithelial cells coagulate, reducing epithelial translucency and causing a white appearance known as the acetowhite reaction. Normal columnar epithelium may display slight whitening that is transient. Higher-grade lesions exhibit faster acetowhite reactions, more pronounced changes, and longer-lasting effects.
Iodine Test
This test complements the acetic acid test when necessary. A cotton swab soaked with 5% iodine solution (Lugol's iodine) is applied to the upper vaginal wall and cervical surface. Iodine staining is observed, with further exploration of the mid and lower vaginal walls if abnormalities are noted. Mature squamous epithelial cells rich in glycogen stain dark brown. Columnar epithelium, immature metaplastic epithelium, keratinized epithelium, and atypical dysplastic epithelium lack glycogen and typically do not stain with iodine.
Assessment and Identification of Abnormal Epithelium
The size, shape, position, and extent of lesions are evaluated. Based on the medical history and colposcopic findings, the need for biopsy and endocervical curettage is determined. Targeted biopsies are performed at one or multiple sites of abnormal or suspicious lesions, and biopsy specimens are labeled by site for pathological examination.
Documentation of Colposcopic Findings
Findings are documented with detailed descriptions of imaging characteristics, biopsy sites are marked, and a colposcopy report is generated along with any necessary follow-up instructions.
Colposcopy Terminology
The International Federation of Cervical Pathology and Colposcopy (IFCPC) updated its colposcopic terminology system in 2011 based on evidence-based medical data, and this system has been in use since then. The standardized terminology enhances the ability of colposcopy to provide evidence for clinical decision-making.
The colposcopic diagnostic terms for the cervix are described as follows:
General Evaluation
This refers to the assessment of the reliability of the colposcopic examination and includes three components:
- Adequacy of the Examination: Evaluates whether the cervix is sufficiently exposed and whether factors affecting the reliability of the examination are present.
- Visibility of the Squamocolumnar Junction (SCJ): Classified as fully visible, partially visible, or not visible.
- Transformation Zone (TZ) Type:
- Type I: The transformation zone is fully visible.
- Type II: The transformation zone is fully visible with the aid of instruments or other adjunctive measures.
- Type III: The transformation zone is either partially visible or not visible at all.
Normal Colposcopic Findings
Normal findings include mature or atrophic original squamous epithelium, ectopic columnar epithelium, squamous metaplasia, and decidual changes during pregnancy.
Abnormal Colposcopic Findings
These include:
- General Description: The location of the lesion (described using clockface orientation), the number of quadrants involved, and the percentage of the area affected.
- Major Abnormalities: Refers to high-grade lesions, including rapid acetowhite reactions, thick acetowhite epithelium, sharply demarcated borders, coarse and irregular mosaic patterns, coarse and irregular punctation, gland openings with cuff-like appearances, acetowhite demarcations within the lesion, and ridge-like protrusions.
- Minor Abnormalities: Refers to low-grade lesions, including thin acetowhite epithelium, irregular boundary patterns, uniform fine mosaic patterns, and uniform fine punctation.
- Non-Specific Findings: Includes leukoplakia, iodine-positive areas, or unstained areas during iodine testing.
Suspicious Features of Invasive Cancer
Suspicious findings for invasive cancer include atypical blood vessels, fragile blood vessels, necrosis, ulceration, and tumors.
Other Findings
These include congenital transformation zones, warts, polyps, inflammation, stenosis, congenital anomalies, post-treatment changes of the cervix, and endometriosis affecting the cervix.