Low-grade squamous intraepithelial lesions: cytologic predictors of biopsy confirmation

Intermediate-grade squamous intraepithelial lesion may be a valid diagnostic/interpretive category

We undertook this study to assess the characteristics of smears with features intermediate between high-grade squamous intraepithelial lesion (HSIL) and low-grade squamous intraepithelial lesion (ISIL). We also wanted to determine how these smears correlate with high risk biopsy diagnosis and to compare this with the biopsy correlation of LSIL and HSIL. Seventy-four squamous intraepithelial lesion (SIL) smears were identified as intermediate-grade SIL smears taken at colposcopy in a 1 year period. They were correlated with concurrent colposcopically guided biopsies. Thirty-five percent of cases with intermediate-grade SIL smears had a biopsy diagnosis of moderate dysplasia or higher as compared with 12% for LSIL 74% for HSIL. This confirmed our hypothesis that intermediate-grade SIL smears have a rate of biopsy diagnosis of moderate dysplasia or higher intermediate to that of LSIL and HSIL.

Pitfalls in the diagnosis of cervical intraepithelial neoplasia 1

OBJECTIVE

This review article outlines the issues involved in (1) the cytologic diagnosis of low-grade squamous intra-epithelial lesion (cervical intraepithelial neoplasia [CIN] 1), (2) histologic diagnosis of CIN 1, (3) the advantages and disadvantages of various management strategies for CIN 1 confirmed by biopsy, and (4) the evolving technology that may be useful for predicting the course of the disease.

MATERIALS AND METHODS

A MEDLINE search was conducted using the search terms cervical intraepithelial neoplasia, low-grade dysplasia, mild dysplasia, low-risk squamous intraepithelial lesion, mild dyskaryosis, HPV, colposcopy, histology, and cytology. RESULTS.: Using a loop electrosurgical excision procedure or cone biopsy assessment of the cervix as the gold standard, a cytologic assessment of CIN 1 alone results in a high false-positive rate (51.5%) and a false-negative rate (24%) for CIN 3. The appropriate second test after low-grade squamous intraepithelial lesion (CIN 1) cytologic results includes repeat cervical cytologic analysis. Subsequent human papillomavirus testing provides no advantage and increases the cost of care. Immediate referral to colposcopy is costly but minimizes the percent of women lost to follow-up. Using a loop electrosurgical excision procedure or cone biopsy assessment of the cervix as the gold standard, the colposcopically directed biopsy may give a false-positive result (11.7%) or false-negative result (up to 31%) for CIN 3. One contributing issue is the moderate interobserver reliability of histologic analysis (kappa= 0.46). There are advantages and disadvantages to both the immediate and expectant management strategies. The most crucial concern for immediate treatment is overtreatment, and that for expectant management the high rate of patients lost to follow-up. Novel technologies, including MIB-1, p16(INK)4a, and genetic assessments, may be helpful in predicting those CIN 1 lesions destined to progress or to persist.

CONCLUSIONS

The cytologic and histologic diagnosis of CIN 1 is fraught with problems related to the subjectivity of the diagnosis. Both management options are also fraught with concerns. Any technique that can better predict disease course would be an advantage to the care of women with this abnormality.

Women with low-grade abnormalities on Pap smear should be referred for colposcopy

AIM

To assess cytological, colposcopic and histological outcomes in women referred to a teaching hospital dysplasia clinic with low-grade changes on screening Pap smear.

METHODS

Analysis of a computerised database.

RESULTS

Repeating the Pap test was of little value. Fifteen percent of women with low-grade changes on the referral smear had biopsy proven high-grade change. There was little difference in biopsy proven high-grade change in women referred with an 'abnormal smear of uncertain significance' (23%) or 'an abnormal smear of uncertain significance-possible high-grade change' (24%).

CONCLUSIONS

Given these findings and the current medico-legal climate, immediate referral of women with low-grade changes on routine cytology is indicated, and seems a safer option than the more conservative approach of a repeat smear in 6 or 12 months. Further study of the usefulness of separating smears of uncertain significance into high-grade and low-grade categories is warranted. Consumer input into recommendations for management of Pap smear abnormalities is required.

The significance of the Papanicolaou smear diagnosis of low-grade squamous intraepithelial lesion cannot exclude high-grade squamous intraepithelial lesion

BACKGROUND

Cervical cytologic specimens that show a low-grade squamous intraepithelial lesion (LSIL) occasionally contain a few cells that are suspicious for, but not diagnostic of, a high-grade squamous intraepithelial lesion (HSIL). In such cases, a diagnosis of LSIL cannot exclude HSIL is rendered. The objective of the current study was to assess the positive predictive value (PPV) for HSIL in follow-up cervical biopsies for these cases.

METHODS

One hundred forty-four women with a Papanicolaou (Pap) diagnosis of LSIL cannot exclude HSIL and their follow-up cervical biopsies were reviewed. Results were compared with a control group of 155 women with a Pap diagnosis of LSIL. A subset of biopsies was tested and typed for human papillomavirus (HPV) DNA by polymerase chain reaction amplification using consensus primers followed by restriction fragment length polymorphism analysis. HPVs were scored as low-risk or high-risk types.

RESULTS

Women with LSIL cannot exclude HSIL had a higher incidence of HSIL (PPV = 29%) on follow-up cervical biopsy than the control group (PPV = 15%, P < 0.01). In addition, SIL, indeterminate grade was diagnosed in 10% of cervical biopsies in the study group as compared with 4% in controls. Review of Pap smears from the study group showed that there were 3 types of cells suspicious for a high-grade lesion: atypical squamous metaplastic cells (62%), atypical keratinized cells (20%), and dysplastic cells of borderline nuclear-to-cytoplasm ratio (18%). HPV analysis confirmed the presence of high-risk HPV types in the study cases with high-grade cervical biopsies.

CONCLUSIONS

Women with a Pap diagnosis of LSIL cannot exclude HSIL appear to be more likely to harbor a high-grade lesion than those diagnosed with LSIL alone. Its use appears warranted. Women with this diagnosis merit appropriate clinical follow-up to exclude HSIL.

Symposium part 1: Should the Bethesda System terminology be used in diagnostic surgical pathology?: Point

During the past 50 years, the histologic classification of cervical intraepithelial neoplasia (CIN) has evolved to incorporate the entire spectrum of genital papillomavirus infections, segregating those lesions with the higher risk of containing prototypic high-risk human papillomavirus types, and recently has meshed with treatment algorithms that include loop electrical excision procedures and follow-up alone. This review describes a classification system that divides CIN into categories of low-grade (CIN 1) and high-grade (CIN 2 and CIN 3). To successfully apply this system, the practitioner must efficiently exclude nonneoplastic entities and base the distinction of CIN 1 from CIN 2/3 on criteria that recognize the effects of viral oncogenes on replicating cells. This is achieved by basing the diagnosis of CIN 1 on uniform polarized epithelial growth, low mitotic index, low mitotic counts, and minimal parabasal cell anisokaryosis and coarse chromatin and CIN 2 on the presence of these features or abnormal mitoses. Simply put, the definition of CIN 2 (or higher) is the presence of atypical immature cells in the biopsy that if seen in a cytologic smear would merit a diagnosis of high-grade squamous intraepithelial lesion. In essence, a successful two-grade system requires careful application of cytologic criteria in a histologic milieu. This model is illustrated in a set of 25 images that underscore the importance of excluding benign changes (with the appropriate use of biomarkers), segregating unusual variants of low-grade squamous intraepithelial lesions, and identifying the morphologic transition to high-grade squamous intraepithelial lesions (CIN 2 or CIN 3) with an acceptable level of reproducibility.

Hybrid Capture Human Papillomavirus Testing as an Adjunct to the Follow-Up of Patients with ASCUS and LGSIL Pap Smears: A Study of a Screening Population

OBJECTIVES

We set out to evaluate Hybrid Capture (Digene Corporation, Silver Spring, MD) testing for human papillomavirus (HPV) in the management of a screening population with atypical squamous cells of undetermined significance (ASCUS) or low-grade squamous intraepithelial lesion (LGSIL).

METHODS

A total of 619 patients with ASCUS or LGSIL Papanicolaou smears were tested for high-risk HPV types. They then were followed at 6-month intervals with Papanicolaou smears and repeat HPV testing. Patients with persistent or progressive disease were referred for colposcopy. HPV results were compared to the most significant follow-up cytological or colposcopic diagnosis to determine whether Hybrid Capture HPV testing was predictive of outcome. A cost analysis was performed.

RESULTS

Follow-up of 12 to 30 months was available for 471 patients (76.1%). Outcome diagnoses for 190 patients who initially tested HPV-positive were as follows: 49% benign, 14% ASCUS, 19% LGSIL, 18% HGSIL, and 0.5% cancer. For 281 patients who initially tested HPV-negative, outcomes were 77% benign, 14% ASCUS, 6% LGSIL, 2% HGSIL, and 0.3% cancer. Twenty-six of the patients with HGSIL had two or more HPV tests, and all these patients had at least one positive result.

CONCLUSIONS

Hybrid Capture testing for high-risk HPV types was predictive of which patients presenting with ASCUS/LGSIL would persist or progress to HGSIL (p < .001). The cost of adding Hybrid Capture testing was intermediate between the cost of cytological follow-up and referral of all patients with ASCUS/LGSIL to colposcopy.

ThinPrep Pap Test: performance and biopsy follow-up in a university hospital

BACKGROUND

The ThinPrep Pap Test (TP), a liquid-based cervical cytology preparation, was approved for use in the U.S. in 1996. The purpose of this study was to compare TP performance and biopsy follow-up studies with a similar population of high risk patients sampled by conventional Papanicolaou (Pap) smear (CS).

METHODS

Diagnostic and specimen adequacy interpretations for 2727 TP direct-to-vial Pap tests from a high risk university hospital practice were compared with 5000 CS preparations from the same physicians taken 1 year previously. Biopsy follow-up studies for the categories of squamous intraepithelial lesion (SIL), carcinoma, and atypical squamous cells of undetermined significance (ASCUS) for each time period and technique were contrasted.

RESULTS

The SIL/carcinoma detection rate increased from 7.7% to 10.5% (P < 0.01) and the ASCUS rate decreased from 12.5% to 6.9% (P < 0.01); the percentage of satisfactory but limited specimens decreased from 19.4% to 10.5% (P < 0.01). Low grade SIL cases increased by 57% (P < 0.01) whereas the 26% increase in high grade SIL cases was not statistically significant. Greater than 90% of ungraded SIL, high grade SIL, and carcinoma cases had abnormal biopsies by both the TP and CS methods. The number of biopsy-confirmed high grade dysplasias and carcinomas was similar in the two groups. A low grade SIL detected by TP was less likely to have an abnormal biopsy (70% vs. 85% for CS). Nevertheless, the 57% increase in low grade SIL diagnoses by TP resulted in more TP patients with dysplastic biopsy diagnoses. Follow-up studies for ASCUS cases diagnosed by either TP or CS were similar, and 21-24% of patients eventually were found to have dysplasia.

CONCLUSIONS

The TP technique appears to lead to the increased detection of low grade SIL lesions, decreased satisfactory but limited samples, and fewer equivocal specimens. No increase in biopsy-confirmed high grade dysplasias and carcinomas was found. Follow-up studies for the ASCUS category were nearly identical to those for CS.

Coexistence of low and high grade squamous intraepithelial lesions of the cervix: morphologic progression or multiple papillomaviruses?

BACKGROUND

The diagnosis of both low (LSIL) and high (HSIL) grade squamous intraepithelial lesions in the same cervical specimen may reflect classification variation, morphologic progression in situ, and, conceivably, different HPV infections. We addressed these possibilities in cervical specimens previously diagnosed as containing both LSIL (condyloma/CIN1) and HSIL (CIN2/3).

METHODS

All cases with a histologic diagnosis of LSIL and HSIL from 1994-1996 were reviewed. On review, lesions were scored as (1) no significant variation in lesion grade (classification discrepancies) and showing a (2) one (CIN1-2) or (3) two (CIN1-3) grade shift in the same case. In cases in which a one or two grade shift was confirmed, low (CIN1) and high (CIN2-3) grade foci were microdissected and extracted DNA analyzed for HPV by PCR and RFLP analysis.

RESULTS

Of 98 cases available for review, 58 (59%) did not exhibit significant variation in grade (classification discrepancy), and 40 (41%) showed a one (25) or two (15) grade shift. Of the latter group both LSIL and HSIL foci were HPV(+) in 26 (65. 0%). The same HPV was present in both LSIL and HSIL foci in 15/15 lesions with a one grade shift (CIN1-2). In contrast, a significantly higher proportion of lesions with a two grade shift (CIN1-3) contained two different HPV types (4/11 vs 0/15; P = 0.01). Combinations of HPVs in the low/high grade foci, respectively, included HPV 11/16 (1), 11/16 + 18 (1), and HPV39/16 (2).

CONCLUSIONS

Lesions containing LSIL and HSIL which span two grades (CIN1 and CIN2) most likely represent morphologic progression in a single infection. Lesions containing CIN1 and CIN 3 may be attributed to both lesion progression and two coincident infections; the latter sometimes present in the same histologic section. The latter phenomenon has implications for both the diagnosis of CIN and interpretation of "morphologic progression" from very low to high grade in the same case.

Histology corresponding to mildly dyskaryotic smears--a study of 190 laser cone biopsied patients

OBJECTIVES

The aim of the study was to evaluate the histological outcome of laser ring biopsies in patients with one or more smears showing cytological mild dyskaryosis where punch biopsies were not performed. The possibilities of predicting histological findings of CIN 2 and CIN 3 were analyzed.

METHODS

The study comprised 190 laser ring biopsied patients with mildly dyskaryotic smears. Eighty-five patients were excluded from the initial 275 because of up- and downgrading of smears. Conization specimens and smears were reviewed by an experienced histopathologist and two experienced cytotechnicians. The histological findings were correlated to smear findings.

RESULTS

Histologically, CIN 2 was found in 60 and CIN 3 in 45 patients (31 and 24%, respectively). The incidence of histological CIN 3 was higher in those with two or more mildly dyskaryotic smears and in those dyskaryotic smears lacking koilocytic change. Mildly dyskaryotic smears without endocervical cells indicated higher incidence of histological CIN 3. The fact that 36 of 96 CIN 2 and 3 lesions (38%) involved only 3 mm or less of the mucosa might be one important explanation for the absence of representative cells in the corresponding smears.

CONCLUSIONS

Our study has shown that a mildly dyskaryotic smear is a strong indicator of CIN 2-3 histologically, especially in those cases without koilocytic cells and in those with repeatedly abnormal smears. The importance of inadequate sampling is indicated by higher incidence of histological CIN 3 in those with less than optimal smears. These findings are some of the factors to be taken into account when planning treatment strategies for this group of patients.

Comparison of the risks of cytologic surveillance of women with atypical cells or low-grade abnormalities on cervical smear: review of the literature

Minor cytological abnormalities--low-grade squamous intraepithelial lesions (LGSIL) and atypical squamous cells of undetermined significance (ASCUS)--are the most frequent abnormalities observed in smears performed in screening for cervical cancer. Surveillance through repeated smears has been proposed as an alternative to immediate colposcopy to reduce cost and avoid overloading colposcopy clinics. The aim of this review is to discuss the advantages and inconveniences of cytological surveillance of women with ASCUS or LGSIL, as reported in the literature. Cervical smears are not sufficient to establish the precise diagnosis of a lesion. In fact, the mean prevalence of normal cervices, high-grade CINs and cancers is estimated to be 58%, 7% and 0.5% for ASCUS and 34%, 27% and 0.2% for LGSIL. Cytological surveillance shows that minor cytological abnormalities regress in 28-69% of cases. In 6-9%, cytological regression masks a high-grade CIN, and a cancer may develop sooner or later in 0.30-1.12% of cases. Cancers often occur in patients temporarily lost to surveillance or in those with normal smears alternating with smears showing minor abnormalities. Strict modalities of surveillance are therefore required. The surveillance has to be carried out with smears repeated every 4-6 months for 2 years. If all smears are normal the regular screening at 3-year intervals may be resumed. On the other hand, an immediate colposcopy is recommended if a new abnormality is observed in these consecutive smears, regardless of its severity and of the time elapsed since the initial abnormality was discovered. With these recommendations in mind, cytological surveillance may slightly reduce the number of colposcopies but without reducing significantly the cost. At present, no arguments based on cost or efficacy clearly favour cytological surveillance over immediate colposcopy.

Clinical role of HPV testing

The subjectivity of morphologic methods contributes to a "swamping" of colposcopic services, excessive costs, overdiagnosis, and overtreatment. HPV DNA testing provides the objectivity required to clarify difficult patient management issues, including follow-up, for low-grade cytologic abnormalities (ASCUS and LSIL), noncorrelating (nonconfirmed) Pap smears, evaluation of nondiagnostic lower genital tract lesions, and cytology and histology laboratory quality assurance. Additionally, favorable preliminary data on HPV testing as a primary screen raise the exciting prospect of potentially lowering costs of cervical cancer-screening programs, while further decreasing the incidence of cervical cancer.

Image cytometry and chemoprevention in cervical cancer

Of the approximately 60 million Pap smears performed in the United States in 1995, about 8% or 5 million will show cytology that is "not negative" (ASCUS, AGCUS, LSIL, HSIL, etc.). Possibly 15% or about 0.7 million of these cases will have positive follow-up by repeated Pap smears, colposcopy or biopsy. More than 4 million will be false-positive smears based on the reference standard of biopsy or repeated smears. If no treatment or medical intervention was offered to the 0.7 million cytologically and histologically positive cases, perhaps 20,000 (3%) would develop into invasive cancer. Of the original 5 million cytologically "not negative" cases, fewer than 0.5% have the potential to develop into invasive cancer. While considerable attention has been paid to false-negatives in Pap screening, the above considerations indicate that the cytological and histological criteria for assessing the malignant potential of "not negative" samples might benefit from some refinement. Until such refinement occurs, any chemoprevention studies in cervix face a formidable signal-to-noise problem--worse than 1:30. This paper presents data from quantitative image cytometry of cervical smears for assessing the malignant potential of various "not negative" cases. We have approached this in two ways--by analyzing dysplastic cell nuclei and by analyzing the nuclei of cytologically normal cells growing in the vicinity of the neoplastic lesion. In both cases, nuclear features describing the distribution of the DNA in the cell nuclei (especially texture features) are the discriminating factors. Future research into the objective assessment of malignant potential of "not negative" cases is outlined.