Smears diagnosed as ASCUS: interobserver variation and follow-up.

The purpose of this study was to apply atypical squamous cells of undetermined significance (ASCUS) criteria from the Bethesda System for Reporting Cervical/Vaginal Cytologic Diagnoses (TBS) to the rescreen of cases previously diagnosed as ASCUS, to compare initial and rescreen diagnoses, and to analyze agreement with follow-up (cytology or histology). Two cytotechnologists (S.B. and M.J.M.) and one cytopathology fellow (M.A.) rescreened 632 cervicovaginal specimens diagnosed as ASCUS between June 1, 1992-December 31, 1995. Age and LMP were provided. Rescreen diagnoses were categorized as within normal limits (WNL), ASCUS, low-grade squamous intraepithelial lesions (LSIL), high-grade squamous intraepithelial lesions (HSIL), or carcinoma (CA). Complete agreement was found in 200 specimens (32%): 31 (15%) WNL; 91 (45%) ASCUS; 77 (38.5%) SIL; and one (0.50%) CA. Follow-up revealed no abnormality in 67% of the cases reclassified as WNL, 49% of the cases reclassified as ASCUS, and 48% of the cases reclassified as squamous intraepithelial lesions (SIL). SIL was found in 29% of cases reclassified as WNL, 29% of specimens rediagnosed as ASCUS, and 34% of cases reclassified as SIL. Partial agreement was found in 391 specimens (62%). In 41 specimens (6%), rescreeners were in complete disagreement, and follow-up revealed 9/41 (22%) SIL or worse; 21/41 (51%) WNL; and 4/41 (10%) inconclusive. Applying established criteria, 14% (91/632) of cases diagnosed as ASCUS resulted in complete agreement, and 30% (190/632) resulted in partial agreement. Follow-up of cases initially diagnosed as ASCUS revealed SIL or CA in 30% of cases. ASCUS is a significant diagnosis warranting careful patient follow-up.

ThinPrep vs. conventional smears in fine-needle aspirations of sarcomas: A morphological and immunocytochemical study.

Very limited data exist describing the characteristics of sarcomas sampled by fine-needle aspiration (FNA) and processed by the ThinPrep (TP) method. We compared the cytopathological and immunocytochemical features of sarcoma aspirates prepared using both the conventional and TP method. We reviewed 70 sarcoma FNAs. Samples were first used to prepare conventional smears and the remainder of the specimen was rinsed in Cytolyt. The average number of slides examined per case was two for the TP method and five for the conventional technique. Immunocytochemistry for different markers was performed in a subset of cases. Sixty-five cases were positive for sarcoma both by conventional and TP methods. Five cases were positive by one method only. Cellularity was higher on conventional slides. In terms of cytoarchitecture, TP slides revealed fewer thick clusters, more single cells that were more evenly distributed, and sometimes distortion of expected cellular arrangements and architectural patterns. Cytomorphological and nuclear details were better preserved on TP slides. The background of TP slides revealed a reduction of blood but also some loss of necrosis and characteristic background tumor features. Immunocytochemical staining revealed superior results on TP slides. TP and conventional slides showed good correlation. TPs were excellent for immunocytochemistry and represent an alternative to conventional smears when expertise in slide preparation is not available. However, TPs may require additional experience in the interpretation of sarcomas, mainly related to the loss of tumor-specific background features. They are useful as an adjuvant to conventional smears in sarcoma diagnoses, particularly when special studies are needed. Diagn. Cytopathol. 1999;21:351-354.

Negative predictive value of pulmonary fine needle aspiration cytology.

Percutaneous fine needle aspiration (FNA) for cytologic examination is an accepted and reliable technique for diagnosing neoplasia. It is less useful, however, in excluding that diagnosis. We performed a retrospective analysis of a consecutive series of pulmonary FNA specimens at Memorial Sloan-Kettering Cancer Center to determine the negative predictive value (NPV) of this technique in the setting of a large cancer hospital. Fifty-seven cases were studied. Six cases (10.5%) were initially diagnosed as negative but acellular and were not further analyzed, and another 6 were lost to follow-up; 24 cases (42.1%) were subsequently confirmed negative by tissue or clinical follow-up, and 21 of the cases (36.8%) were proven positive for malignancy by repeat aspiration, tissue diagnosis or clinical means. Of these 21 cases, 1 was misdiagnosed as negative, and review demonstrated malignant cells on the slide; 3 of the 21 cases should have been initially rejected as unsatisfactory, and 18 of the 21 contained material sufficient for a cytologic diagnosis but not representative of the lesion. On follow-up the false-negative cases showed primary adenocarcinoma, epidermoid carcinoma, lymphoma, metastatic breast carcinoma and metastatic sarcoma. Specific benign diagnoses were made on the initial cytologic preparation in three cases. No benign tumors were found. The NPV in our series was 53.3%, comparable to values in previous reports. The single largest factor contributing to false-negative diagnoses is sampling error, and we recommend repeat aspiration when no specific benign diagnosis is made. In addition, we suggest that the diagnoses of negative for malignant cells and insufficient for diagnosis or acellular be considered separate categories.