Cervical Anatomy• The cervix is composed of columnar epithelium, which lines the endocervical canal, and squamous epithelium, which covers the exocervix. The point at which they meet is called the squamocolumnar junction (SCJ).
Squamocolumnar Junction• The SCJ rarely remains restricted to the external os. Instead, it is a dynamic point that changes in response to puberty. Pregnancy, menopause and hormonal stimulation.• In neonates, the SCJ is located on the exocervix. At menarche, the production of estrogen causes the vaginal epithelium to fill with glycogen.• Lactobacilli act on the glycogen to lower the pH, stimulating the subcolumnar reserve cells to undergo metaplasia.
SCJ• Metaplasia advances from the original SCJ inward, toward the external os and over the columnar villi. This process establishes an area called the transformation zone.• The transformation zone extends from the original SCJ to the physiologically active SCJ.• As the metaplastic epithelium in the transformation zone matures. It begins to produce glycogen and eventually resembles the original squamous epithelium, colposcopically and histologically.
CIN Zone• In most cases, CIN is believed to originate as a single focus in the transformation zone at the advancing SCJ.• The anterior lip of the cervix is twice as likely to develop CIN as the posterior lip, and CIN rarely originates in the lateral angles.• CIN is most likely to begin either during menarche or after pregnancy, when metaplasia is most active. Conversely, after menopause a woman undergoes little metaplasia and is at a lower risk of developing CIN.• Oncogenic factors are introduced through sexual intercourse. Although several agents, including sperm, seminal fluid histones, trichomonas, chlamydia, and herpes simplex virus have been studied, it is now known that HPV plays an important role in the development of CIN.
Normal Transformation Zone• The basal layer is a single row of immature cells with large nuclei and a small amount of cytoplasm.• The parabasal layer includes two to four rows of immature cells that have normal mitotic figures and provide the replacement cells for the overlying epithelium.• The intermediate layer includes four to six rows of cells with larger amounts of cytoplasm in a polyhedral shape separated by an intercellular space. Intercellular bridges. Where differentiation of glycogen production occurs, can be identified with light microscopy.• The superficial layer includes five to eight rows of flattened cells with small uniform nuclei and a cytoplasm filled with glycogen. The nucleus becomes pyknotic, and the cells detach from the surface (exfoliation). These cells form the basis for Papanicolaou (Pap) testing.
Columnar Epithelium• Columnar epithelium has a single layer of columnar cells with mucus at the top and a round nucleus at the base.• The glandular epithelium is composed of numerous ridges, clefts, and infoldings and when covered by squamous, metaplasia, leads to the appearance of gland openings.• Technically, the endocervix is not a gland, but the term gland opening often is used.
Metaplastic Epithelium• Metaplastic epithelium, found at the SCJ, begins in the subcolumnar reserve cell. Under stimulation of lower vaginal acidity, the reserve cells proliferate, lifting the columnar epithelium.• The immature metaplastic cells have large nuclieii and a small amount of cytoplasm without glycogen. As the cells mature normally, they produce glycogen, eventually forming the four layers of epithelium.• The metaplastic process begins at the tips of the columnar villi, which are exposed first to the acid vaginal enviroment. As the metaplasia replaces the columnar epithelium, the central capillary of the villus regresses, and the epithelium flattens the epithelium.
Metaplastic Epithelium Cont..• The deeper clefts, however, may not be completely replaced by the metaplastic epithelium, leaving mucus-secreting columnar epithelium trapped under the squamous epithelium.• Some of these glands open onto the surface; others are completely encased, with mucus collecting in nabothian cysts.• Gland openings and nabothian cysts mark the original SCJ and the outer edge of the original transormation zone.
Human Papillomavirus• The cytlogic changes of HPV were first recognized by Koss and Durfee in 1956 and given the term koilocytosis.• Their significance was not recognized until 20 years later, when Meisels and colleagues reported these changes in mild dysplasia.• Molecular biologic studies have shown high levels of HPV DNA and capsid antigen, indicating, .• Koilocytes are characterized by perinuclear halos, well- defined cell borders, and nuclear hyperchromasia, irregularity, and enlargement.
HPV -• Productive viral infection in these koilocytic cell. The HPV genome has been found in all grades of cervical neoplasia.• Infection with HPV is the primary cause of cervical cancer. As the CIN lesions become more severe, the koilocytes disappear, the HPV copy numbers decrease, and the capsid antigen disappears, indicating that the virus is not capable of reproducing in less differentiated cells.• Instead, portions of the HPV DNA become integrated into the host cells. Integration of the transcriptionally active DNA into the host cell appears to be essential to malignant growth.• Malignant transformation requires the expression of E6 and E7 oncoproteins produced by HPV.
HPV - Pathogenesis• Cervical cancer cell lines that contain active copies of HPV-16 or -18 (SiHa, HelLa, C4 Ski) show the presence of HPV – 16 E6 and E7 oncoproteins.• The percentage of intraepithelial neoplasia attributed of HPV infection approaches 90%.• Only certain types of HPV count for about 90% of high-grade intraepithelial lesions and cancer (HPV-16, -18, -13, -33, -39, -45, -51, -52, - 56, and -58). Type 16 is the most common HPV found in invasive cancer and in CIN 2 and CIN 3, and it is found in 47% of women with cancer in these stages.• HPV-16 is not very specific; it can be found in 16% of women with low- grade lesions and in up to 14% of women with normal cytology.• Human papillomavirus type -18 is found in 23% of women with invasive cancers, 5% of women with CIN 2 and CIN 3, 5% of women with HPV and CIN 1, and fewer than 2% of patients with negative findings.• Therefore, HPV -18 is more specific than HPV -16 for invasive tumors
HPV – Pathogenesis Cont..• Usually, HPV infections do not persist. Those that do persist can remain latent for many years. Most women have no clinical evidence of disease, and the infection is eventually suppressed or eliminated.• Other women exhibit low-grade cervical lesions that may regress spontaneously.• In most women, the infection will clear in 9 to 15 months.• Persistent high-risk HPV infection increases the risk of high-grade disease and the development and maintenance of CIN 3.• Factors that may have a role in this progression include smoking, contraceptive use, infection with other sexually transmitted diseases, or nutrition.• Any factor that influences the integration of HPV DNA into the human genome may cause progression to invasive disease.
Human Papillomavirus Vaccine Development• The development of a vaccine for HPV could lead to a potential reduction in the incidence of cervical cancer and its precursor lesions, other associated cancer (anal, penile, vaginal, vulvar) and genital warts.• Recently three separate trials have been performed to test the efficacy of various HPV vaccines.• Each trial was able to show that the vaccine they were using was efficacious in preventing persistent HPV infection.• Another trial of a bivalent L1 VLP vaccine for the prevention of HPV -16 and -18 used a similar protocol.• The results of this trial found that the efficacy of the vaccine was more than 85% for persistent infection and 93% for cytologic abnormalities.
Papanicolaou Test• The Pap Test has been successful in reducing the incidence of cervical cancer by 79% and the mortality by 70% since 1950.• In three recent reviews of the accuracy of cervical cytology assessment, the sensitivity of the Pap test in detecting CIN 2-3 ranged from 47% to 62% and the specificity ranged from 60% to 95%.• Approximately 30% of new cancer cases each year result from women who have undergone Pap testing.
Screening Guidelines• The American Cancer Society (ACS) updated recommendations of 2002 states that screening with conventional Pap testing should occur every year.• Screening should begin at the age of 21 or within 3 years of the onset of sexual activity, and screening can stop at age 70 if there has been no abnormal Pap test result in the past 10 years.• The ACS also states that screening after hysterectomy for benign disease is not necessary.• HPV DNA testing combined with cervical cytology as a screening technique for women older than age 30.• When the results of both tests are negative, the woman does not have to be retested for 3 years. The negative predictive value of a double negative test exceeds 99%.
Low-grade Squamous Intraepithelial Lesions• The ALTS trial confirmed the validity of the current practice of performing colposcopy to evaluate a single LSIL result.
High-grade Squamous Intraepithelial Lesions• Any women with a cytologic specimen suggesting the presence of HSIL should undergo colposcopy and directed biopsy.• After colposcopically directed biopsy and determination of the distribution of the lesion, ablative therapy and destruction of the entire transformation zone should be performed.
Colposcopy Findings Acetowhite Epithelium• Epithelium that turns white after application of acetic acid (3%-5%) is called acetowhite epithelium.• The application of acetic acid coagulates the proteins of the nucleus and cytoplasm and makes the proteins opaque and white.
Leukoplakia• Leukoplakia is white plaque. In colposcopic terminology, this plaque is white qpithelium visible before application of acetic acid.• Leukoplakia is caused by a layer of keratin on the surface of the epithelium. Immature squamous epithelial cells have the potential to develop into keratin-producing cells or glycogen-producing cells.• In the vagina and on the cervix, the normal differentiation is toward glycogen. Keratin production is abnormal in the cervicovaginal mucosa.• Leukoplakia can be caused by HPV; keratininzing CIN; keratinizing carcinoma; chronic trauma from diaphragm, pessary, or tampon use; and radiotherapy.• Because it is not possible to see through the tick keratin layer to the underlying vasculature during colposcopy, such areas should undergo biopsy to rule out keratinizing carcinoma.
Mosaic Pattern in Epithelium• Terminal capillaries surrounding roughly circular or polygonal- shaped blocks of acetowhite ephithelium crowded together are called mosaic because their appearance is similar to mosaic tile.• Mosaicism tends to be associated with higher-grade lesions and CIN 2 and CIN 3. Atypical Vascular Pattern• Atypical vascular patterns are characteristic of invasive cervical cancer and include looped vessels, branching vessels, and reticular vessels.
Endocervical Curettage• A cytobrush is sufficient for sampling the endocervical canal.Cervical Biopsy• The cervical biopsy is performed at the area most likely to have dysplasia.• If the lesion is large or multifocal, multiple biopsies may be necessary to be assured of a complete sample of the affected tissue.
Correlation of Findings• Ideally, both the pathologist and colposcopist should review the colposcopic findings and the results of cytologic assessment, cervical biopsy, and endocervical sample before deciding therapy.
Histologic Terminology CIN 1• The spontaneous regression rate of biopsy-proven CIN 1 is 60% to 85% in prospective studies.• The regressions typically occur within a 2 year follow-up with cytology and colposcopy.• This information has let to the recommendation that patients who have biopsy diagnoses of CIN 1 with satisfactory colposcopy and who agree to the evaluation every 6 months may be treated by observation with Pap testing performed at 6 and 12 months or HPV DNA testing at 12 months.• After two negative test results or a single negative HPV DNA test, annual screening may be resumed.
CIN 1• Colposcopy and repeat cytology at 12 months is another acceptable alternative.• It the lesions progress during follow-up or persist at 2 years, ablative treatment should be performed. Regression of CIN 1 decreases after 24 months, with the regression rate becoming the same as for CIN 2 by 5 years.• For patient with persistent CIN 1after 24 months, the choice of treatment is optional.• Expectant management is still acceptable, as long as the patient is cooperative with follow-up.
CIN 2 and CIN 3• All CIN 2 and 3 lesions require treatment. This recommendation is based on a meta-analysis showing that CIN 2 progresses to CIS in 20% of cases and to invasion in 5% Progression of CIS to invasion is 5%.• The preferred treatment for CIN 2 and 3 has become LEEP. These techniques allow a specimen to be sent for evaluation and enable the pathologist to identify occult microinvasive cancer or adenomatous lesions to ensure these lesions have been treated adequately.• The persistent and recurrent disease rates are 4% to 10%.
Treatment of CIN• All therapeutic modalities carry an inherent recurrence rate of up to 10% cytologic follow-up at about 3 month intervals for 1 year is necessary.• Ablative therapy is appropriate when the following conditions exist: – There is no evidence of microinvasive or invasive cancer on cytology, colposcopy, endovcervical curettage, or biopsy. – The lesion is located on the ectocervix and can be seen entirely. – There is no involvement of the endocervix with high-grade dysplasia as determined by colposcopy and endocervical curettage.
Cryotherapy• Cryotherapy destroys the surface epithelium of the cervix by crystallizing the intracellular water, resulting in the eventual destruction of the cell.• The temperature needed for effective destruction must be in the range of (-20 to -30 C).• Nitrous oxide (89 C) and carbon dioxide (-65 C) produce temperatures below this range and therefore, are the most commonly used gases for this procedure.• Cryotherapy should be considered acceptable therapy when the following criteria are met: – Cervical intraepithelial neoplasia, grade 1 to 2 – Small lesion – Ectocervical location only – Negative endocervical sample – No endocervical gland involvement on biopsy.
Laser Ablation• Laser ablation has been used effectively for the treatment of CIN. However, because of the expense of the equipment as well as necessity for special training, laser ablation has fallen out of favor.• Additionally, because much early CIN is being managed conservatively, the need for any kind of ablation is decreasing.
Loop Electrosurgical Excision• If the power is high (35-55 watts) and the wire loop is small (0.5 mm), the effect will be electrosurgical, and the tissue will have little thermal damage.• The actual cutting is a result of steam envelope developing at the interface between the wire loop and the water-laden tissue.• This envelope is then pushed through the tissue, and the combination of electron flow and acoustical events separates the tissue.• After the excision, a 5-mm diameter ball electrode is used, and the power is set at 50 watts.• The ball is placed near the surface so that a spark occurs between the ball and the tissue.• This process is called electrofulguration, and it results in some thermal damage that leads to hemostasis.• Recent research ha shown that LEEP is associated with an increased risk of overall preterm delivery.• Intraoperative hemorrhage, postoperative hemorrhage, and cervical stenosis can occur but at acceptably low rates.
Conization• Conization is both a diagnostic and therapeutic procedure and has the advantage over ablative therapies of providing tissue for further evaluation to rule out invasive cancer.• Conization is indicated for diagnosis in women with HSIL based on a Pap test under the following conditions: – Limits of the lesion cannot be visualized with colposcopy. – The SCJ is not seen at colposcopy. – Endocervical curettage (ECC) histologic findings are positive for CIN 2 or CIN 3. – There is a substantial lack of correlation between cytology, biopsy, and colposcopy results. – Microinvasion is suspected based on biopsy, colposcopy, or cytology results. – The colposcopist is unable to rule out invasive cancer.
• There are some situations in which hysterectomy remains a valid and appropriate (although mandatory) method of treatment for CIN: – Microinvasion – CIN 3 at limits of conization specimen in selected patients – Poor compliance with follow-up – Other gynecologic problems requiring hysterectomy, such as fibroids, prolapse, endometriosis, and pelvic inflammatory disease.