Comparison of ThinPrep and conventional preparations in pancreatic fine-needle aspiration biopsy.

Use of ThinPrep preparation for fine-needle aspiration biopsy (FNA) is gaining popularity. However, there may be a difference in the morphology and the operating characteristics between ThinPrep and conventional methods. The objective of this study was to compare the accuracy of the two methods and to address the pitfalls of ThinPrep preparation in pancreatic FNA. A computer search identified 67 pancreatic FNAs with both conventional smears and ThinPrep preparation during a 19-mo period. These cases, obtained under endoscopic ultrasound-guidance, consisted of 47 malignant neoplasms (44 ductal carcinomas, two mucinous neoplasms, and one islet cell tumor) and 20 benign lesions. Direct smears were prepared first and the remaining material was then put into PreservCyt Solution for ThinPrep slides. All slides were reviewed and the cytologic diagnoses were correlated with histologic and clinical follow-up. Five conventional and 16 ThinPrep specimens were unsatisfactory due to insufficient cellularity. These cases were excluded from the analysis. Among the 62 cases evaluated by conventional preparation, 77% (34) were diagnosed as positive and 14% (seven) atypical/suspicious by conventional smears. For the 51 ThinPrep specimens, 58% (22) were interpreted as positive and 31% (12) atypical/suspicious. The sensitivity, specificity, and accuracy of diagnosing a malignancy were 77%, 100%, and 84% for conventional smears and 58%, 100%, and 67% for ThinPrep preparation, respectively. There were no false positives with either method. However, three benign lesions were interpreted as atypical/suspicious with ThinPrep preparation because of the presence of single atypical cells with distinct nucleoli. One of the two mucinous neoplasms was incorrectly diagnosed with ThinPrep preparation because of lack of mucin. The diagnostic accuracy of pancreatic FNA using ThinPrep is inferior to that of conventional smears. This may be partly due to the use of split sample technique resulting in scant cellularity in ThinPrep preparation and partly due to the differences in morphology between the two preparations. Therefore, the current morphologic criteria may need modification for ThinPrep preparation in pancreatic FNA.

Glandular cell atypia on Papanicolaou smears: interobserver variability in the diagnosis and prediction of cell of origin.

BACKGROUND: The 2001 Bethesda System recommended qualification of atypical glandular cells (AGC) to indicate the site of origin and separated endocervical adenocarcinoma in situ (AIS) from "AGC favor neoplastic" as a specific diagnostic category. To the authors' knowledge, the literature evaluating the reproducibility of Papanicolaou (Pap) smear diagnosis of glandular cell abnormalities with emphasis on the cell of origin is limited. The aim of the current study was to investigate whether a variety of benign to neoplastic glandular lesions can be reliably classified on Pap smear with regard to diagnosis and cell of origin. METHODS: Twenty-three conventional Pap smears (CPS) with glandular cellular changes varying from benign to adenocarcinoma (ACA) were reviewed by six observers. They were asked to categorize each smear according to cell of origin (endocervical vs. endometrial) and diagnosis (benign, AGC, or ACA). Kappa statistics were used to evaluate interobserver agreement and correlation of interobserver agreement with experience. RESULTS: There was no consensus among observers for both the origin of the cells and the diagnosis. Interobserver agreement for site was poor (kappa < 0.4) especially in the AGC category. Unanimous agreement for site was reached for 7 of 23 smears (30%). Two of five endocervical AIS were classified as endometrial and another two were classified as benign by four observers. Interobserver agreement was poor in all diagnostic categories (kappa < 0.4) and showed slight correlation with level of experience. Unanimous agreement for diagnosis was reached for only 2 smears (9%). Three of 11 (27%) smears demonstrating preneoplastic/neoplastic processes were diagnosed as benign by 3 observers. Three (25%) benign CPS were diagnosed as ACA by 2 observers. Accurate prediction of the final histologic diagnosis by observers varied from 30% to 87% and did not correlate closely with experience. CONCLUSIONS: Cytologic diagnosis of glandular lesions by CPS was problematic and suffered from significant interobserver subjectivity.

Interobserver variability in assessing adequacy of the squamous component in conventional cervicovaginal smears.

We compared the interobserver reproducibility of estimating the adequacy of the squamous component of conventional Papanicolaou (Pap) smears using traditional and newly proposed criteria. Forty conventional Pap smears with varying degrees of squamous cellularity were reviewed by 13 observers who evaluated adequacy (satisfactory vs unsatisfactory) based on the traditional criterion of estimating 10% slide coverage. After being introduced to the new criterion and the reference images, the observers reevaluated adequacy on the same set of smears, using the new criterion and the reference images. With the original criterion of 10% slide coverage, 15 smears had a unanimous designation; the overall kappa value was 0.49 (P < .001). With the newly proposed adequacy criterion and reference images, 17 smears had a unanimous designation; the overall kappa value was 0.60 (P < .001). The difference in the kappa correlation coefficients was statistically significant (P = .007). While traditional and newly proposed criteria resulted in fair interobserver agreement, it seemed that the newly proposed criterion, along with the use of reference images, for evaluating adequacy of the squamous component of conventional Pap smears results in better interobserver reproducibility.

Comparison of five antibodies as markers in the diagnosis of melanoma in cytologic preparations.

We determined the sensitivity and specificity of 3 novel antibodies (microphthalmia transcription factor [Mitf], Melan-A, and tyrosinase) as markers for melanoma in cytologic preparations and compared the results with those of commonly used markers (S-100 protein [S-100] and HMB-45). We stained 72 cell blocks from 40 patients with melanoma and 32 with nonmelanocytic malignant neoplasms with antibodies against S-100, HMB-45, Mitf, Melan-A, and tyrosinase. Histologic correlation was available in more than 95% of cases. Nuclear stainingfor Mitf and cytoplasmic stainingfor S-100, HMB-45, Melan-A, and tyrosinase in more than 10% of tumor cells was considered positive. All 3 novel markers demonstrated sensitivity superior to S-100 and HMB-45. HMB-45, Melan-A, and Mitf demonstrated specificities of 97%. S-100 protein and tyrosinase were less specific. Sensitivity and specificity for the combination Mitf+/Melan-A+ were 95% and 100%, respectively, whereas they were 80% and 100%, respectively, for S-100+/HMB-45+. Mitf Melan-A, and tyrosinase are sensitive markersfor epithelioid melanoma. Mitf and Melan-A seem more specific than S-100 and tyrosinase. An antibody panel consisting of Mitf and Melan-A is superior to a panel of S-100 and HMB-45 in the diagnosis of melanoma in cytologic specimens.