Cell preparation methods and criteria for sample adequacy. International Academy of Cytology Task Force summary. Diagnostic Cytology Towards the 21st Century: An International Expert Conference and Tutorial

ISSUES

Cell Preparation Methods Standardized fixation and optimal staining Sampling of cervix, sampling error, homogenization of sample, subsampling Assessment of liquid-based preparations: efficacy and economic impact Training and transitional procedures before full implementation of new technologies Criteria for Sample Adequacy Clinician responsibility for collecting and providing representative sample to laboratory Collection instruments, number of slides Cellular content of samples: evidence of transformation zone (TZ) sampling, number of squamous cells present, obscuring factors Screening issues CONSENSUS POSITION The conventional cervical smear remains the standard method of cervical cancer screening but has limitations in individual test sensitivity and specificity. Sample takers should: (1) receive appropriate training in sample collection, (2) be held responsible for providing the laboratory with appropriate samples, and (3) have their performance monitored. The instruments used for sampling should collect cells from both the ectocervix and endocervix; optimally, TZ sampling, represented by the presence of endocervical or squamous metaplastic cells, should be identifiable in samples other than atrophic specimens. The adequacy of a specimen (as judged microscopically) does not guarantee that it is representative of the cervix. Each cytology report should include a comment on cellular content/adequacy of the specimen. Liquid-based preparations may overcome many of the inherent problems with the conventional cervical smear.

ONGOING ISSUES

We need further data on the cost-effectiveness of making two slides from cervical specimens and/or using two samplers rather than a single one. Do we have enough information to make recommendations as to the appropriate type of sampler to be used in particular situations, such as routine screening? What is the best method of screening for/detecting endocervical glandular neoplasia? How are such terms as unsatisfactory and inadequate defined in cervical cytology classifications other than the Bethesda System? What number and types of epithelial cells should be present (visualized) in a cervical smear or liquid-based preparation for it to be considered adequate? Do we need to have evidence of TZ sampling in specimens taken during the follow-up period after treatment of squamous intraepithelial lesion or after detection of endocervical glandular neoplasia? What criteria for obscuring factors, such as blood and inflammation, should be used in assessing adequacy? Cost-benefit analyses of utilizing liquid-based preparations are needed. Should we inform women about the technical details of the test methods available or chosen by the laboratory? Are women in a position to decide which method is the most appropriate to assess their cervical scrape sample? We need to obtain more information about the properties of proprietary liquid fixative/transport media with respect to inactivation of viral pathogens, tuberculosis and other bacterial pathogens and suitability for immunobiologic and molecular tests, etc. We need to obtain more information on the use of stoichiometric stains and the limitations of Papanicolaou stain for image analysis systems. The use of liquid-based preparations for nongynecologic cytopathology and ancillary tests must be considered, including criteria for adequacy. We need to obtain more information on the time required for and best methods of training experienced cytotechnologists to become competent at assessing liquid-based cervical preparations.

Evaluation of the ThinPrep Pap test as an adjunct to the conventional Pap smear

OBJECTIVE

To evaluate the ThinPrep Pap test as an adjunct to the conventional Pap smear.

DESIGN AND SETTING

Prospectively collected cervical samples were split for independent screening at a large specialised private gynaecological pathology practice in Sydney.

MAIN OUTCOME MEASURES

Detection of additional significant abnormalities (cervical intraepithelial neoplasia 1, or more severe); changed management recommendations from "repeat smear in 12 months" or "...six months" to "colposcopy", a reduction in unsatisfactory reports.

RESULTS

35,560 paired (split-sample) conventional and ThinPrep slides were prepared. Significant abnormalities were detected in 724 conventional smears (2%). Additional significant abnormalities were found in 85 ThinPrep slides whose corresponding conventional smear was negative or unsatisfactory even after review, representing a 12% increase in the detection of significant abnormalities. As a result of the addition of ThinPrep, management recommendations were changed from "repeat smear in 12 months" or "...six months" to "colposcopy" for 89 of 1669 women whose conventional Pap smears showed minor non-specific changes or papillomavirus. There were 1258 conventional smears (3.5%) that were unsatisfactory compared with 235 ThinPrep slides (0.7%); for only 74 samples (0.2%) were both slides unsatisfactory.

CONCLUSIONS

The addition of the ThinPrep Pap test improves detection and clinical management of cervical abnormalities, and reduces the number of unsatisfactory samples which would otherwise require repeat tests.

Transtracheal aspiration using rigid bronchoscopy and a rigid needle for investigating mediastinal masses

BACKGROUND

Use of the flexible needle via the fibreoptic bronchoscope to aspirate mediastinal nodes or masses has largely superseded the use of the rigid needle via the rigid bronchoscope. However, the yield at fibreoptic bronchoscopy is relatively low, although this improves with the use of a wider gauge needle. In this study the sensitivity and the safety of rigid needle sampling of the mediastinum in the diagnosis of lung cancer is evaluated.

METHODS

Transtracheal needle aspiration (TTNA) was performed with the rigid bronchoscope and a rigid aspiration needle under general anaesthesia using a previous computed tomographic (CT) scan as a guide to the sample site. A cytopathologist immediately examined the specimens for adequacy and preliminary diagnosis, thus determining the number of aspirations.

RESULTS

Twenty four patients were evaluated. The diagnostic sensitivity of TTNA was 88%. This led to a management decision in 21 patients. There were no false positives and no complications.

CONCLUSIONS

TTNA using the rigid bronchoscope with CT scanning and a cytopathologist present is a sensitive and safe way of diagnosing lung cancer in patients with a mediastinal mass or enlarged mediastinal nodes.

Transtracheal needle aspiration

A series of 27 transtracheal needle aspiration biopsies performed on 25 patients were reviewed. A rigid bronchoscope and rigid needle were used. The biopsies were performed as staging procedures in patients with bronchogenic carcinoma, or to obtain diagnoses in patients with mediastinal adenopathy. A cytopathologist attended 11 biopsies and microscopically examined a direct smear to determine adequacy. Repeat biopsies were taken at the time if necessary. A diagnosis was obtained in 9/11 (81%) of these cases. Only 3/16 biopsies (18.8%) performed in the absence of a pathologist were diagnostic. All negative cases were subsequently found to have disease (2 sarcoidosis, 13 cancer) by other methods including mediastinoscopy in 5 cases. In the patient group sampled, the technique of rigid needle and rigid bronchoscope with a cytopathologist in attendance resulted in a much higher sensitivity for the test than has been previously reported.

Morphologic and morphometric features of low grade serous tumours of the ovary

Peritoneal washings from twelve patients with serous tumours of the ovary were studied. Six patients had borderline serous tumours (BSTs), and six had grade one adenocarcinomas. Papanicolaou stained slides were assessed for nine morphologic parameters; background, single cells, size of papillary fragments, contour of papillary fragments, psamomma bodies, cytoplasmic vacuoles, nuclear pleomorphism, nuclear membrane contour, and nucleoli. The slides were destained and restained by the Feulgen method for assessment, with a computer based image analysis system (CAS100, Cell Analysis Systems, Inc., Elmhurst, IL), of DNA content, nuclear size, and nuclear roundness. The contour of the papillary fragments (P = 0.004) and the presence of nuclear pleomorphism (0.019) were distinguishing characteristics. All six BSTs were diploid while three of the six adenocarcinomas had aneuploidy. Two exhibited polyploid DNA distribution and one exhibited diploid DNA distribution. The pooled data for the nuclear size and roundness showed little difference in the modal values, although the nuclei of the adenocarcinoma cells were slightly larger than those of the borderline cells (54 sq. microns vs. 46 sw. microns). However, the coefficients of variation (CVs) for each of these parameters were larger in the adenocarcinoma group than in the borderline group (59.7 vs. 36.4% for size and 33.5 vs. 17.8% for roundness). Although the sample size is small, the data suggest that aneuploidy is rare in borderline tumours. In addition, the presence of papillary groups with irregular contours and nuclear pleomorphism (reflected in higher CVs for nuclear size and roundness) both occur more commonly in adenocarcinomas than in borderline tumours and may be of predictive value in distinguishing the two groups.

The utility of ancillary studies in pediatric FNA cytology

We evaluated the diagnostic contribution of adjunct studies performed on aspirated material in the work-up of pediatric fine-needle aspiration (FNA) biopsies. Ancillary studies were performed on 54 of 136 (39.7%) pediatric FNA biopsies during a 5-year period. In 23 (16.9%) cases, immunocytochemical (ICC) studies, consisting of immunoperoxidase staining of direct smears and/or cell blocks or flow cytometric immunophenotyping, were performed. The studies were adequate in 14 cases (60.9%), suboptimal in five cases (21.7%), and inadequate in four cases (17.4%). Of the adequate and suboptimal cases, the ICC data helped to narrow the differential diagnosis or classify the disease process in eight cases (42.1%), confirmed cytologic impression in nine cases (47.4%), and gave contradictory results in two cases (10.5%). Adequate material for electron microscopy (EM) was obtained in 14/19 cases (73.7%). Ultrastructural studies were diagnostic, or helped classify the disease process in five cases (35.7%), confirmed the cytologic impression in four cases (28.6%), helped exclude diagnostic considerations in three cases (21.4%), and were judged to be non-contributory in two cases (14.3%). Cytogenetic studies revealed six of seven cases (all neoplasms) to have abnormal karyotypes. Special stains for organisms performed on smears from 25 cases including Ziehl-Neelsen, Gomori methenamine silver (GMS), Gram, and Warthin-Starry (WS) were negative except for 1/16 GMS and 4/9 Gram stains. In summary, we found that with appropriate case selection, ancillary studies performed on aspirated material can provide useful information in pediatric FNA cytology.

Fine needle aspiration cytology of renal infarcts. Cytomorphologic findings and potential diagnostic pitfalls in two cases

The fine needle aspiration (FNA) cytologic features of two cases of renal infarction are presented. Both patients did not have a classic clinical history for infarction, and the radiologic findings were suggestive of neoplasia. In one of our cases, necrotic glomeruli and tubules were present, which suggested the correct diagnosis of renal infarction and permitted appropriate early treatment. In the other case, groups of atypical renal tubular cells undergoing repair secondary to the infarction was misinterpreted as renal cell carcinoma. This case illustrates that renal infarction, like pulmonary infarction, can be a potential pitfall for a false-positive cytologic diagnosis of malignancy in FNA biopsy. A conservative approach is warranted when there is scanty cellularity and atypical cells having features of a repairlike reaction are present.

Pediatric fine-needle aspiration biopsy

A total of 135 fine-needle aspiration (FNA) biopsies from varying sites were performed in 123 children (mean, 10.5 years; range, one day to 18 years) over a five-year period. One hundred thirty (96.3%) biopsy specimens were satisfactory for evaluation. Seventy-nine cases were nonneoplastic (60.8%); among these cases, a specific diagnosis of infectious disease was made in 17 (13.1%). A diagnosis of neoplastic disease was made in 50 (38.5%) cases, of which 14 (10.8%) were benign, 28 (21.5%) were malignant, and 8 (6.2%) were neoplasms of uncertain biologic potential. The sensitivity of pediatric FNA biopsies was 90.6%, specificity 100%, positive predictive value 100%, negative predictive value 94.7%, and efficiency of the test 96.5%. There were no false-positive diagnoses and there were four false-negative diagnoses, three of which involved aspirates of the central nervous system (CNS). Ancillary studies, including immunocytochemistry (20 cases), electron microscopic examination (18 cases), microbiologic culture (8 cases), cytogenetic studies (7 cases), and flow cytometry (3 cases), were performed on the aspirated material, enabling a more specific diagnosis or supplying additional information in many cases. Definitive diagnosis by FNA biopsy enabled radiation therapy and/or chemotherapy to be administered for unresectable malignant neoplasms, provided material for culture of infectious lesions, identified benign lesions not needing surgery, and aided the surgeon in planning the extent of surgery in resectable malignant neoplasms. These results support the greater use of FNA biopsy in the pediatric population.

Natural history and significance of esophageal squamous cell dysplasia

Balloon-mesh cytologic screening for esophageal cancer done in 255 asymptomatic high-risk United States veterans (age greater than 40 years, ethanol abuse for greater than 20 years, and cigarette smoking greater than 20 pack years) identified 37 patients with squamous cell dysplasia. Of the 37 patients with dysplasia, 28 were re-evaluated prospectively at 6-month intervals for up to 36 months by balloon-mesh cytology, esophagoscopy with vital staining and biopsies, chest radiographs, oropharyngeal examination, and indirect laryngoscopy. During prospective follow-up evaluation, cytology specimens were repetitively normal in 16 patients (57%), showed inflammatory changes in eight patients (29%), persisted as dysplasia in two patients (7%) (both had endoscopic and histologic evidence of esophagitis), and progressed to carcinoma in two patients (7%) (one esophageal, one laryngeal). Although histologic findings concurred with the resolution of dysplasia, biopsy specimens were characterized by a similar difficulty in distinguishing dysplasia from inflammation. Erroneous histologic diagnoses of carcinoma in situ were made in two patients with reflux esophagitis evident endoscopically and confirmed during the course of a 24-36 month follow-up period. The authors conclude that squamous cell dysplasia detected by balloon-mesh cytology is seldom a precursor of esophageal cancer in the high-risk U.S. population but, rather, is often related to esophagitis. Thus, balloon-mesh cytology has limited use as a screening method for the early detection of esophageal cancer in the United States.

Comparison of the Papanicolaou and Feulgen staining methods for DNA quantification by image analysis

The possibility of using archival cytology material to study the evolution of neoplastic disease with regard to DNA content abnormalities was investigated. The accuracy of measuring the integrity optical density (OD) of nuclei that correlates to DNA amounts of those nuclei, on slides stained by the Papanicolaou method, was assessed and compared with a standard Feulgen method. Our data on rat liver nuclei peritoneal washings from patients with ovarian cystadenofibromas and ovarian cystadenocarcinomas suggested that analysis of cytological material using the Papanicolaou method is not reliable and that destaining the slides followed by Feulgen staining provides an optimal and reliable method of DNA quantification.