Diagnostic Accuracy of Fine-Needle Aspiration Cytology Alone and With Cell Block Preparation for Palpable Breast Lesions: A Prospective Study in Central India

BackgroundFine-needle aspiration cytology (FNAC) is a rapid and minimally invasive test for palpable breast lesions, but limited architecture and sampling variability can reduce sensitivity.Cell block preparation may complement smears by preserving tissue fragments in paraffin sections.This study estimated the diagnostic accuracy of FNAC and the incremental diagnostic yield obtained by adding cell block interpretation in the histologically verified subset, while describing cell block adequacy in the entire enrolled cohort. Materials and methodsThis prospective observational diagnostic accuracy study enrolled 74 consecutive patients with palpable breast lesions at a tertiary-care center in Bhopal, India, from May 2024 through December 2025.A first dedicated pass was used for conventional smears and a second for plasma-thrombin cell block preparation.FNAC was classified using the International Academy of Cytology Yokohama system.Histopathology was available for 46 clinically biopsied or excised lesions and served as the reference standard.Exact 95% confidence intervals were calculated from the two-by-two counts, and FNAC and combined interpretation were compared using an exact two-sided McNemar test among the 46 verified participants. ResultsThe mean age was 36.4 ± 14.0 years, and 70 participants (94.6%) were female.All FNAC smears were adequate; 58 lesions (78.4%) were benign, 1 (1.4%) atypical, 5 (6.8%) suspicious, and 10 (13.5%) malignant.Ten cell blocks (13.5%) were inadequate or hemorrhagic.Histopathology identified 35 benign and 11 malignant lesions.FNAC yielded 81.82% sensitivity (95% CI, 48.22%-97.72%),100% specificity (95% CI, 90.00%-100%), and 95.65% accuracy (95% CI, 85.16%-99.47%).Combined interpretation yielded 90.91% sensitivity (95% CI, 58.72%-99.77%),100% specificity (95% CI, 90.00%-100%), and 97.83% accuracy (95% CI, 88.47%-99.94%).Paired analysis showed one discordant result favoring combined interpretation and none favoring FNAC (exact McNemar p = 1.000). ConclusionsCombined interpretation showed numerically higher sensitivity and accuracy than FNAC alone in the histologically verified subset, but the small number of malignant lesions, wide confidence intervals, and partial verification preclude a definitive claim of superiority.Cell blocks are best used as an adjunct within clinical-radiological-pathological correlation; discordant or concerning lesions still require histopathology.