Fine needle aspiration biopsy of the breast: Importance of benign, nonspecific results

The authors attempted to determine the importance of benign but nonspecific findings from an adequate sample obtained with image-guided, fine-needle aspiration biopsy (FNAB) of the breast. Four hundred thirty-seven image-guided FNAB specimens obtained over a 4-year period were reviewed. Pathologic results, mammograms, sonograms, and radiology reports were correlated for all cases described as benign but nonspecific on the basis of cytologic results. Lesion characterization, type of imaging, and targeting accuracy were assessed. Follow-up method (imaging and/or clinical follow-up, core biopsy, open biopsy) was determined. Of the 427 lesions, 99 (23%) were designated benign but nonspecific. In 75 of the cases, biopsy (core or open) had been performed or there had been at least 2 years of follow-up at the time of this study. Of these, 32 lesions were benign on the basis of follow-up, 27 (36%) were benign at secondary biopsy, seven (9%) were malignant at final biopsy, and nine (12%) were lost to follow-up. Five of the seven cancers occurred in the 1st year of the study; these lesions were sampled for biopsy based on their mammographic appearance. The lesions in an additional 24 patients were benign after at least 1 year of follow-up. Benign, nonspecific imaged-guided FNAB results are reliable if targeting is accurate and if the mammographic findings support a benign process.