Fine needle aspiration biopsy of palpable breast lesions. Review and statistical analysis of 1875 cases.

Fine needle aspiration biopsy (FNAB) is an increasingly accepted method for investigating palpable breast nodules. We reviewed our experience with a consecutive series of 1875 FNABs performed using 21 or 23 gauge butterfly needles. Correlation was made with histology (524 cases) or clinical follow-up (2-70 months). Cytological diagnoses utilized histopathological terminology and were categorized as: unsatisfactory (93 or 4.96%); no evidence of malignancy (1295 or 69.07%); atypical (183 or 9.76%); suspicious (42 or 2.24%); malignant (262 or 13.97%). Of the 1571 benign aspirates, 220 or 14% were followed by excisional biopsy because of clinical suspicion, atypia or hypocellularity. Of these aspirates, 198 were benign while 22 proved to be malignant (one in situ ductal, one intracystic papillary, two tubular, one cribriform, seven ductal nos, three in situ and five infiltrating lobular carcinomas, two large cell lymphomas). Malignancy was detected histologically in 12.9% of unsatisfactory, 3.06% of benign but often hypocellular, 8.16% of atypical, 97.62% of suspicious and 100% of malignant aspirates. Considering only histologically verified breast aspirates and including suspicious cytodiagnoses, FNAB had a sensitivity of 93.23%, a specificity of 99.50%, positive and negative predictive values of 99.62% and 90%, and an overall diagnostic accuracy of 95.61%. This series clearly shows that FNAB effectively evaluates palpable breast lesions when careful consideration is given to clinical judgement, specimen procurement, diagnostic criteria and a clinically relevant reporting style.