Information, discrimination and divergence in cytology. III. Optimization of classification of Papanicolaou smears

The performance of a cytology laboratory can be objectively quantitated as the total discrimination, a defined quantity of information. The total discrimination is dependent on the number of categories used in gynecologic cytology and on the corresponding histologic states; over-classification results in a higher rate of misinformation and reduced total discrimination. Total divergence is another measure of the association between cytologic categories and histologic states; in contrast to the total discrimination, the total divergence does not require a one-to-one correspondence between the cytologic categories and the histologic states. Using data from the Gynecologic Cytology Laboratory of the University of Minnesota, the total discrimination was maximized when gynecologic cytology used three categories of diagnosis, consisting of (1) normal, atypical benign or reactive atypia, (2) cervical intraepithelial neoplasia (CIN) and (3) all malignancies. The use of four categories, (1) normal, atypical benign or reactive atypia, (2) mild or moderate dysplasia, (3) severe dysplasia or squamous carcinoma in situ and (4) all malignancies, was almost equally informative. Observations on the total divergences resulted in similar conclusions. These findings generally support the recommendation of the consensus workshop sponsored by the National Cancer Institute (the Bethesda System nomenclature) to group all degrees of CIN into two large categories.     

Screening errors in cervical cytologic screening

A total of 555 cervical smears, originally classified as Papanicolaou classes I and II, from women in whom three years later cytologic findings consistent with moderate dysplasia, severe dysplasia, carcinoma in situ and invasive cancer were diagnosed were reviewed in order to estimate the screening error. The initial diagnosis proved to be underestimated in 17.5% of the smears. The two diagnoses correlated in 70.2% of the smears while 12.3% of the smears that contained no abnormality were judged to be inadequate for making a diagnosis, probably representing sampling errors. Quality-control measures to reduce these errors are briefly summarized.     

False-negative results in cervical cytologic studies

The appropriate interval between cervical cytologic screening studies is a matter of considerable controversy, with a major consideration being the problem of false-negative results. To determine the rate of false-negative cervical cytologic results in our laboratory and to determine how these failures occur, tissue-proven cases of carcinoma in situ, invasive squamous-cell carcinoma, endocervical adenocarcinoma and lymphoid malignancy involving the cervix with negative Papanicolaou smears obtained within one year prior to the tissue diagnosis were reviewed. Over the four-year period from 1980 through 1983, 339 patients had tissue-proven cervical malignancies. Of these, 66 had false-negative Papanicolaou smears, representing a 20% overall false-negative rate. These false-negative smears were rescreened. For all types of cervical malignancy, the majority of errors were due to sampling. No malignancy was missed disproportionately by either cytotechnologists or cytopathologists. We plan to utilize these data for quality control purposes and for continued review of future performance.     

Diagnostic accuracy of squamous cervical lesions studied in spatula-cytobrush smears

The cytologically positive cases found in 25,300 cervical smears of spatula samples and 6,168 smears prepared by combined spatula-Cytobrush sampling were analyzed. The diagnostic accuracy (the correlation between the cytologic and histologic diagnoses) was the same for both types of sampling. As to the histologic diagnosis, the rates of severe dysplasia, carcinoma in situ and squamous carcinoma in the spatula-Cytobrush group were more than twice as high as in the spatula group. In the spatula group, the majority of abnormal cells was of the mature type. In the spatula-Cytobrush group, the majority of smears contained a mixture of immature and mature abnormal cells. The more immature lesions, which are often located higher in the endocervical canal, seem to be better sampled by the Cytobrush. The results indicate that the Cytobrush reaches areas that a spatula cannot reach, resulting in a higher diagnostic efficiency.     

Ethnic patterns of cytologic abnormalities in cervical smears in suriname, a high-risk area for cervical cancer

OBJECTIVE: To determine the prevalence of cytologic abnormalities in cervical smears from women attending the first organized screening program in Suriname and to compare the prevalences in 4 Surinamese ethnicities with different cervical carcinoma incidences. STUDY DESIGN: Cervical scrapes were taken from women with 4 different ethnicities: Maroons, Amerindians, Javanese and Hindustani. Papanicolaou staining and cytologic screening were performed on 807 cervical smears. RESULTS Cervical cytologic abnormalities were seen in 13.4%, of which 8.1% (62 of 764) had atypical changes, 2.6% (20 of 764) had mild and 2.6% (20 of 764) had moderate and severe dysplasia/carcinoma in situ (CIS). The cytologic abnormalities varied between the ethnicities: 42.1% (83 of 197) in the Maroons and 2.3% (4 of 176), 5.0% (9 of 183) and 3.0% (6 of 208) in the Javanese, Amerindians, and Hindustani, respectively. CONCLUSION: The high prevalence of moderate and severe dysplasia/CIS in all ethnicities correlates with the high cervical carcinoma incidence in Suriname. A significantly higher prevalence of mild abnormalities in the Maroons was observed; it did not reflect the relatively low cervical cancer incidence in this ethnicity. However, this can be explained by the possibility that these women have a different sexual lifestyle, leading to a higher prevalence of     

Cytologic diagnosis of vaginal papillary squamotransitional cell carcinoma. A case report

BACKGROUND: Papillary squamous and squamotransitional cell carcinomas of the cervix and vagina are infrequent morphologic variants of squamous cell carcinoma that may be underdiagnosed due to a bland histologic appearance. To our knowledge, this entity has not been previously detected by Pap smear evaluation. CASE: Vaginal wall pap smears were collected from a patient with a previous hysterectomy for microinvasive cervicovaginal squamous cell carcinoma and extensive carcinoma in situ. The smears were characterized by: (1) large, darkly staining, three-dimensional, branching, papillary epithelial fragments with prominent fibrovascular cores and lined with loosely cohesive epithelial cells; (2) a highly cellular background population of dissociated single epithelial cells with features of severe dysplasia, including hyperchromatic, coarse chromatin; scant, delicate, frayed cytoplasm and karyorrhectic debris; (3) syncytial aggregates of severely dysplastic epithelial cells morphologically similar to the single cells; and (4) lack of a recognizable, morphologically distinct "transitional cell" population. CONCLUSION: Papillary squamotransitional cell carcinoma of the vagina is a rare morphologic variant of squamous cell carcinoma that should be distinguished from benign vaginal squamous papillomas, condylomatous lesions and verrucous carcinoma. However, this lesion is also related to human papillomavirus infection, particularly the high-risk types. Papillary squamotransitional cell carcinoma can be suspected on Pap smear when high grade squamous intraepithelial lesion features are found in combination with three-dimensional papillary tissue fragments with prominent fibrovascular cores.     

DNA-cytometric diagnosis of prospective malignancy in borderline lesions of the uterine cervix

Interactive DNA cytometry was used for the diagnosis of prospective malignancy in 48 smears with borderline lesions (mild and moderate dysplasias) of the uterine cervix. In addition, 183 smears with benign squamous epithelia, 38 with carcinoma in situ and 7 with invasive squamous carcinoma were also measured. Nuclear Feulgen-DNA measurements were performed using various methods, and the resulting data were analyzed by an algorithm for a DNA-cytophotometric diagnosis of malignancy. The results were compared with the data on follow-up and subsequent histologic studies in these cases. There was no false-positive diagnosis in the 183 benign smears and only 1 false-negative diagnosis in the 76 histologically proven squamous-cell carcinomas, which yields a specificity of 100% and a sensitivity of 98.6%. The sensitivity for the detection of subsequent histologically proven malignancy in cases with cytologically mild or moderate dysplasia amounted to 97%. In 13 borderline cases, there was a mean interval of 21 months between the taking of the cytologic smear on which the DNA diagnosis of malignancy was made and the date on which the histologic confirmation of malignancy was made. In 17% of the cytologically dysplastic cases, the DNA diagnosis of malignancy was not verified by subsequent histologic investigation. These results indicate that interactive DNA cytometry is able to detect prospective malignancy in smears from borderline lesions of the uterine cervix with a high sensitivity.     

Glandular lesions of the cervix on thin-layer Pap tests. Validity of cytologic criteria used in identifying significant lesions

OBJECTIVE: To determine the cytologic features that are most helpful in characterizing significant glandular lesions of the cervix observed on the ThinPrep (TP) Pap test (Cytyc Corp., Boxborough, Massachusetts, U.S.A.) and to compare these features with those published for conventional smears. STUDY DESIGN: Thirty-nine TP preparations with cytologic evidence of glandular lesions of the cervix and histologic and/or clinical correlation were studied. These lesions included (1) 11 cases of benign/reactive conditions; (2) 10 cases of adenocarcinoma in situ (AIS), of which 1 had both AIS and carcinoma in situ; (3) 1 case of invasive adenocarcinoma; (4) 15 cases of squamous intraepithelial lesions and squamous cell carcinoma, including 4 with glandular involvement, and (5) 2 cases of adenosquamous cell carcinoma. These cases were reviewed by the first author without knowledge of the histologic diagnosis. Twenty-five previously published cytologic criteria were used to evaluate glandular cells on TP slides. Statistical analysis was performed using Fisher's exact test to determine the significance of the features studied. RESULTS: All glandular lesions had cytologic features on TP similar to those previously described on conventional smears. However, TP slides demonstrated enhanced nuclear features but less-preserved architectural patterns. Reactive lesions showed minimal overlapping without hyperchromasia or mitotic figures and with normal nuclear/cytoplasmic ratios. AIS and invasive adenocarcinoma cases had similar features. Increased cellularity and overcrowding were prominent, whereas feathering, rosettes and cell strips were present but subtle. CONCLUSION: Glandular lesions of the cervix on TP slides shared many of the characteristic features reported for conventional smears. However, nuclear details were more pronounced in TP slides, while architectural patterns, although present, were relatively subtle.     

Extrauterine malignancies. Role of Pap smears in diagnosis and management.

OBJECTIVE: To further elucidate the cytologic manifestations of extrauterine malignancies, to evaluate their possible distinction from primary cervical malignancies and to analyze their clinical significance and role in staging. STUDY DESIGN: Papanicolaou (Pap) smears in 33 cases with abnormal cells originating in histologically proven extrauterine carcinomas were evaluated. These cases came from the files of the Medical College of Pennsylvania and Lankenau Hospitals. RESULTS: Ovary, gastrointestinal tract and breast were the three most frequent primary sites, accounting for 28 of the 33 cases (85%). The histologic types encountered were adenocarcinoma, 29 cases (88%); mucoepidermoid carcinoma, 1 (3%); small cell carcinoma, 1 (3%); cloacogenic carcinoma and large cell lymphoma, 1 (3%). The following diagnoses were rendered at the time of initial evaluation: adenocarcinoma consistent with metastasis, 21 cases; carcinoma, primary versus metastatic, 2; adenocarcinoma, suspicious for endometrial primary, 2; suspicious for carcinoma, 1; and atypical glandular cells, 7. CONCLUSION: The yield for positive Pap smear diagnoses in extrauterine malignancies is best in patients with an established diagnosis of a primary neoplasm. The degree of tumor differentiation and extent of tumor involvement did not appear to correlate with diagnostic yield. There appeared to be no statistically significant association of tumor diathesis with primary versus metastatic carcinoma and presence or absence of documented local involvement of the endometrium, cervix or vagina. Therefore, while Pap smears can serve as a diagnostic tool in the evaluation of extrauterine malignancies, they are best utilized as an adjunct to tumor staging and patient management.     

The validation of cervical cytology. Sensitivity, specificity and predictive values

Statistics and methods for the validation of the results of cytologic screening for cervical cancer and its precursors were examined. Many of the methods commonly used, including the calculation of sensitivity and specificity on raw data, contain flaws that undermine their conclusions. Using a large computerized database of 748,871 cytologic screenings of 277,842 women over a ten-year period, the value of screening was examined. Only subsequent histologic examinations within one year were accepted to validate positive initial cytologic diagnoses; only two subsequent cytologic screenings within the next three years were accepted to validate negative initial cytologic diagnoses that had not been followed by a histologic examination. Cases not meeting these criteria were excluded from the initial analysis. From these data, the predictive value of a negative cytologic examination was determined to be 99.8%; the predictive value of a positive cytologic examination was 73.4% for an initial diagnosis of mild-to-moderate dysplasia, 90.6% for a diagnosis of severe dysplasia/carcinoma in situ, 94.5% for a diagnosis of carcinoma in situ or microinvasive carcinoma and 95.5% for an initial diagnosis of invasive carcinoma. Cases with an initial "questionable" cytologic diagnosis had a positive predictive value of only 64.0%. Extrapolation from the validated cases to the entire screened population showed an overall sensitivity of 80% and a specificity of 99.4% for cytologic screening for cervical cancer. The sensitivity was slightly lower for mild and moderate dysplasia (78.1%) and slightly higher for carcinoma in situ and severe dysplasia (81.4%) and invasive carcinoma (82.3%).     

Preoperative brush and impression cytology in ocular surface squamous neoplasms

OBJECTIVE: Preoperative cytologic diagnoses of ocular surface squamous neoplasms were evaluated and compared with histologic diagnoses. STUDY DESIGN: Impression cytology (Millipore filter paper) and brush cytology were applied to 32 patients who had conjunctival neoplasms. Papanicolaou-stained cytologic preparations and hematoxylin and eosin-stained histologic sections were examined by light microscopy. RESULTS: The brush technique was used on 27 patients; impression cytology was applied in 5 cases. Cytologic and histologic diagnoses were concordant in 26 cases. Squamous cell carcinoma or carcinoma in situ was diagnosed in 18 and dysplasia in 4 cases. Squamous metaplasia and normal-appearing conjunctival epithelial cells were diagnosed cytologically in four cases; of those histologic diagnoses, one was pterygium and three, conjunctival nevus. Four cases revealed discrepancies between the cytologic and histologic preparations. There was one false positive result, and one case was subconjunctival invasion of basal cell carcinoma of the eyelid. CONCLUSION: Impression and brush cytology are fast, cost-effective, reliable and noninvasive diagnostic tools for ocular surface squamous neoplasms. However, the brush technique has several advantages over impression cytology.     

Clinical significance of atypical glandular cells by the 2001 Bethesda System in cytohistologic correlation

OBJECTIVE: To evaluate incidence, cytology findings and pathology outcome of atypical glandular cells (AGC) in Pap smears according to the 2001 Bethesda criteria. STUDY DESIGN: From 103,073 consecutive Pap smears, 113 (0.1%) AGC cases were identified. Of these, 91 (80%) had adequate histologic evaluation included in this study. RESULTS: Abnormal histology findings were seen in 38 patients (42%). Final pathology results revealed 14 endometrial adenocarcinomas, 5 endocervical adenocarcinomas, 1 cervical squamous cell carcinoma, 1 endometrial stromal sarcoma, 6 other malignancies, 4 endocervical adenocarcinomas in situ, 4 cases ofendometrial complex byperplasia, 1 case of endocervical glandular dysplasia and 2 cases of cervical intraepithelial neoplasia 3 with glandular involvement. Women with AGC, favor neoplasia, were more likely to have significant pathology than those with AGC, not otherwise specified, 74% vs. 33% (p = 0.002). Some characteristic background cytologic findings were also noticed in most cases of endometrial, fallopian tube and endocervical adenocarcinoma. CONCLUSION: A diagnosis of AGC is more clinically significant by the 2001 Bethesda System, especially the "AGC, favor neoplastic" category. Some background cytologic features are important because they are indicators of malignancy.     

Morphological and molecular aspects of cancerogenesis in the lung

Morphology and some molecular aspects of hyperplastic (bronchial basal cell hyperplasia and alveolar cell hyperplasia), metaplastic (squamous metaplasia), preneoplastic and early neoplastic (dysplasia in squamous metaplasia, cancer in situ and atypical alveolar cell hyperplasia) changes were studied in 180 lungs resected due to non-small cell lung cancer: 106 cases (58.9%) of squamous cell carcinoma, 42 (23.3%) of adenocarcinoma and 32 (17.8%) of large cell carcinoma. P53 protein and PCNA expressions were detected immunohistochemically (using formalin-fixed, paraffin-embedded sections). DNA extracted from the microdissected P53-positive cells was analysed for point mutations in the P53 gene. No P53 immunostaining was observed in normal mucosa, hyperplasia of basal cells, squamous metaplasia without and with minor and moderate dysplasia of bronchial mucosa as well as alveolar cell hyperplasia. Overexpression of P53 protein occurred in 3 out of 12 (25%) cases of severe bronchial dysplasia, 5 out of 11 (45.5%) cases of intraepithelial carcinoma and 6 out of 45 (13.3%) cases of alveolar cell hyperplasia. Using direct sequencing, mutations in the P53 gene were detected in 11 out of 14 (87%) P53-immunopositive samples, including all severe dysplasias, all carcinomas in situ and 3 of 6 alveolar cell hyperplasias. A significant association was observed between PCNA expression and preinvasive as well as invasive lesions. The data clearly show that lung resected due to primary cancer ought to be treated as "field cancerization" in which one can find early morphologic events of multi-step cancerogenesis. P53 protein alterations and P53 gene mutations can occur before invasion and its frequency depends on the degree of dysplasia.     

Nonaspiration-needle smear preparations of pulmonary lesions. A comparison of cytology and histology

Material for cytologic smears was obtained from pulmonary lesions in 146 patients at the Ohio State University between 1979 and 1984 using Rotex or Lee screw needles. Corresponding histologic specimens were available for comparison in 77 of these cases. Diagnoses of malignant neoplasms made by cytologic evaluation (55 cases) were confirmed by the corresponding histologic specimens in 93% of those cases. Possible explanations for the cytologic false-positive diagnoses of malignancy are presented. Correlations between the cytologic and histologic diagnoses of the morphologic type of tumor were 100% for adenocarcinoma, 75% for squamous-cell carcinoma and 20% for large-cell undifferentiated carcinoma. The correlation was 100% for small-cell carcinoma when the histology specimen represented the tumor. Nonneoplastic benign lesions diagnosed cytologically had corresponding benign histologic diagnoses in 94% of the cases. These results compare favorably with those reported for other fine needle aspiration studies of pulmonary lesions. The advantages of using Rotex needles as compared to fine needle aspiration are discussed.     

AgNOR counts in cervical smears under normal and other cytopathologic conditions

OBJECTIVE: To investigate the diagnostic value of AgNOR counts in cervical smears in the process of cervical carcinogenesis and in discriminating the different grades of squamous intraepithelial lesion (SIL). STUDY DESIGN: Silver nitrate staining for AgNOR counts was performed in 50 cervical smears of cytologically diagnosed normal, inflammatory, low grade SIL (LSIL) (mild dysplasia), high grade SIL (HSIL) (moderate and severe dysplasia) and squamous cell carcinoma. The smears were derived from the ongoing routine outpatient cytology screening at Queen Mary's Hospital, Lucknow, India. RESULTS: In normal and inflammatory smears, the number of AgNOR dots varied from 1 to 2, in mild dysplasia from 2 to 4, in moderate dysplasia from 4 to 6 and in severe dysplasia from 6 to 8. Frank cervical carcinoma cases revealed 8-10 dots. Thus, a progressive increase in AgNOR counts was observed when the severity of pathologic lesions increased. Statistical analysis revealed a significant difference in AgNOR counts between normal and inflammatory smears, but it was highly significant between inflammatory and LSIL cases, between LSIL and HSIL, and between severe dysplasia and frank malignancy. CONCLUSION: This study underscored the diagnostic importance of AgNOR counts, especially in discriminating between LSIL and HSIL of the cervix. Another study is under way to assess the potentiality of AgNOR counts as tumor markers in cervical carcinogenesis.     

Cytological aspects of uterine cervical adenocarcinoma, adenosquamous carcinoma and combined adenocarcinoma-squamous carcinoma: appraisal of diagnostic criteria for in situ versus invasive lesions

Cytological aspects of uterine cervical adenocarcinoma, adenosquamous carcinoma and combined adenocarcinoma-squamous carcinoma: appraisal of diagnostic criteria for in situ versus invasive lesions
This paper reports the cytological findings based on air-dried smears in a retrospective series of 143 cases of endocervical adenocarcinoma, combined adenocarcinoma-squamous carcinoma and adenosquamous carcinoma drawn from the files of the BC Cancer Registry. Cervical cytology smears were available before biopsy in 131 patients, but in 18 cases the cytology showed no abnormality. Malignant changes or high-grade atypia of glandular and/or squamous cells (defined as moderate or severe dyskaryosis) were detected in 103 cases. In 46 cases, only a high-grade squamous abnormality was detected. Low-grade glandular and/or squamous lesions were detected in nine cases and one showed atypical endometrial-type glands. The cervical smears of 64 cases were reviewed in detail to determine the important cytomorphological criteria of in situ and invasive adenocarcinoma in air-dried smears, the technique used for preparing PAP smears in British Columbia. Endocervical cells were absent in four cases. Numerous (>10) groups of glandular cells were present in 51 cases. Important clues to the diagnosis of adenocarcinoma included crowding of nuclei, stratification of nuclei, loss of polarity, syncytial balls and papillary groups of glandular cells, nuclear enlargement, nuclear pleomorphism, and the presence of free-lying atypical glandular cells. Nuclear hyperchromatism, chromatin pattern, nuclear borders, nuclear membranes, and numbers and morphology of nucleoli were not helpful criteria in our material. Criteria enabling reliable distinction between in situ and invasive adenocarcinoma and/or mixed adenocarcinoma-squamous carcinoma could not be established.     

Histologic and cytologic patterns of lung cancer in 2,580 men and women over a 15-year period

This paper describes the relative frequencies and changes in the morphologic patterns of lung cancer, as documented in the histologic and cytologic specimens from 2,580 patients diagnosed and treated at Duke University Medical Center over a period of 15 consecutive years. During the first five years, the relative frequencies of the various types of lung cancers were, in descending order, squamous cell carcinoma (43.1%), large cell undifferentiated carcinoma (22.5%), adenocarcinoma of the acinar type (18.6%), small cell undifferentiated carcinoma (11.6%), bronchioloalveolar carcinoma (3.5%) and adenosquamous carcinoma (0.7%). During the second and third five-year periods, squamous cell carcinoma remained the most common neoplasm, but declined to 35.7%, while adenocarcinoma of the acinar type became the second most common lung cancer at 22.0%. The absolute and relative incidences of lung cancer in women showed a striking increase from 21.8% to 29.9%. During this same period, adenocarcinoma of the acinar type replaced squamous cell carcinoma as the most common primary lung cancer in women.     

Aspiration cytology of the conjunctival surface

OBJECTIVE: To evaluate a method of obtaining conjunctival cells that utilizes aspiration of the conjunctival surface. STUDY DESIGN: Eighteen eyes from 16 patients with epibulbar lesions underwent aspiration of the conjunctival surface using a tuberculin syringe without a needle. The aspirated cells were prepared by the cytocentrifuge or Millipore filter technique. The lesions were subsequently biopsied, and the cytologic and histologic diagnoses were compared. RESULTS: Diagnoses of the conjunctival lesions, in decreasing order of frequency, were conjunctival intraepithelial neoplasia (dysplasia, carcinoma in situ), squamous cell carcinoma, squamous metaplasia, nevus, lymphoma and inflammation. In this feasibility study, the cytologic diagnosis accurately correlated with the histologic diagnosis in most cases. There were two cases in which the cytologic diagnosis led to the correct histologic diagnosis. CONCLUSION: Aspiration cytology of the conjunctival surface is useful in obtaining diagnostic material and may be used as a guide to where a biopsy should be performed. Limitations include inadequate samples and lack of observer experience.     

Association of human papillomavirus and Chlamydia infections with incidence cervical neoplasia

Incidence cervical neoplasia is defined as disease that becomes manifest during a given period of observation. Association with preceding genital infections having characteristic cytologic findings would seem to be more likely for incidence than for prevalence cases since the usual long latency period of carcinoma in situ (CIS) could allow resolution of infectious processes. For this reason, it was elected to examine the preceding Papanicolaou smears from patients with tissue-confirmed incidence CIS or invasive epidermoid carcinoma. There were 67 women with biopsy-proven CIS or invasive carcinoma of the uterine cervix identified in the files of the University of New Mexico Cytopathology Laboratory from 1966 to 1982 who had two initial negative smears as well as smears at intervals of three years or less. All cytologic smears prior to tissue diagnosis were rescreened for confirmation of cytologic atypia or its absence as well as for morphologic evidence of human papillomavirus (HPV) or chlamydial infections. Control cases matched for age, gravidity, ethnicity and number of smears were reviewed in an identical manner. Koilocytes indicative of HPV infection were found in 17 index cases (25%) and 5 controls (7%) (p = 0.005). Chlamydial infections were identified in 18 index cases (27%) and in 4 controls (6%) (p = 0.001). The times required for conversion from smear negativity to malignancy were determined for each incidence case. The results showed great variability but suggest that the progression to malignancy is not hastened in women with antecedent HPV or chlamydial infections. Our results indicate that the presence of koilocytes and/or chlamydial inclusions in cervical smears serves to identify a group of women with a significantly increased risk of developing cervical carcinoma, even in the absence of concurrent dysplasia.     

Interobserver variability in cytologic subclassification of squamous intraepithelial lesions--the Bethesda System vs. World Health Organization classification

The aim of the study was to compare interobserver variability for The Bethesda System (TBS) and World Health Organization (WHO) classification of cervical squamous intraepithelial lesions. A total of 1,000 conventional Papanicolaou smears (156 positive and 884 negative) were examined "blindly" by three cytologists and one cytotechnician. The degree of observer agreement was expressed by kappa statistics using a program for the calculation of interobserver variation and association "Agree" (Svanholm and Jergensen, 1989). Kappa (kappa) was determined for each cytologic diagnosis within a particular classification and total for either classification. The association with and separation from other diagnoses was determined for each cytologic diagnosis in the form of conditional probability (P(j)). In WHO classification, the diagnoses of dysplasia media and dysplasia gravis showed poor reproducibility (kappa = 0.114 and kappa = 0.259, respectively), the diagnosis of dysplasia levis good reproducibility (kappa = 0.639), and the diagnosis of carcinoma in situ excellent reproducibility (kappa = 0.762). WHO classification yielded pool kappa of 0.741. In TBS classification, the diagnosis of LSIL showed good, and HSIL excellent reproducibility (kappa = 0.542 and kappa = 0.763, respectively). TBS classification yielded pool kappa of 0.699. Dysplasia media (P(j) = 0.121) and dysplasia gravis (P(j) = 0.274) were found to be morphologically poorly defined, and carcinoma in situ (P(j) = 0.777) and dysplasia levis (P(j) = 0.651) well defined diagnoses. LSIL was morphologically moderately defined (P(j) = 0.587) and HSIL well defined (P(j) = 0.789) diagnosis. Accordingly, TBS does not substantially improve diagnostic reproducibility of the cytologic diagnoses of squamous intraepithelial lesions, while providing considerably less information to the clinician than the four-grade dysplasia/CIS terminology, thus eliminating the opportunity of choosing a different procedure for the diagnosis of dysplasia media, which is of utmost importance in the population of young nulliparae.