Nonpalpable breast lesions: accuracy of prebiopsy mammographic diagnosis.

Mammograms of 220 patients who underwent spot localization for removal of nonpalpable breast lesions were reviewed for accuracy of interpretation. Results of subsequent biopsy indicated malignancy in 77 cases. The interpretations of mammograms obtained before biopsy were incorrect in 71 cases (27 false-negative and 44 false-positive studies). Among the false-negative cases, 70% of the abnormalities were determined histologically to be noninfiltrative cancers. An aggressive screening program with preoperative localization and biopsy is needed in questionable cases, since mammographic signs of early or nonpalpable malignancy are often subtle and nonspecific.