Cyto-morphologic correlation of equivocal C3 and C4 breast lesions

Abstract

Background: National Cancer Institute (NCI) formulated a five-tiered system for reporting cytological smears from the breast. Of these, C1, C2 and C5 are usually unequivocal. The equivocal categories C3 (atypical probably benign) and C4 (suspicious probably malignant) need to be evaluated to determine their cytomorphologic correlation and thus provide useful information on the degree of clinical weight that can be put on them in patient management. Methods: A retrospective study of cytological smears made from palpable breast lesions performed over a 5-year period from 2008 to 2012. The C3 and C4 smears were then compared with final histological diagnoses for these categories and their diagnostic value calculated. Result: There were 1,162 smears taken in the five years, 200 (17.2%) of which had subsequent histology. Of the 200 smears 20 were C3 and 27 were designated as C4. Subsequent histology upgraded 7 (35%) of the C3 cases to malignant and downgraded 4 (14.8%) of the C4 cases to benign. The overall Suspicious Rate was 23.5% with sensitivity of 76.7%, specificity of 76.5%, positive predictive value and negative predictive values of 85.2% and 65.0% respectively. Conclusion: A fair degree of clinical reliance can still be placed on cytologically categorized C3 and C4 breast smears. However, the rate of reporting of these categories can be reduced with availability of ancillary radiological techniques such as mammography and ultrasonography.