Fine needle aspiration biopsy of the breast : influence of the number of passes and the sample size on the diagnostic yield

: The sensitivity of fine needle aspiration (FNA) biopsy of the breast as a function of the number of aspirations performed on any given lesion was investigated. Four separate aspirations each were performed on over 400 lesions of the breast, 93 of which yielded a cytologic diagnosis. The incremental diagnostic yields of each subsequent aspiration were tabulated. The first aspirate of the sequence gave the greatest yield, with smaller incremental yields on the second through the fourth aspirates. Benign and malignant lesions gave similar results, as did palpable and nonpalpable lesions (the latter being usually smaller in size). A mathematical extrapolation of the data indicates that three or four aspirations of any given lesion provide the optimal yield within the limits of practicality. This performance of multiple FNA biopsies is particularly important when the pathologist does not perform the biopsy, or is unable to assist in the immediate interpretation of the specimen to assess its adequacy.