Sonographically guided biopsy of suspicious microcalcifications of the breast: a pilot study

OBJECTIVE: The purpose of this study is to evaluate the use of sonographic guidance for biopsy of mammographically detected suspicious microcalcifications. SUBJECTS AND METHODS: Twenty-three patients with suspicious microcalcifications detected on mammography (15 associated with masses or distortion; eight with microcalcifications alone) underwent sonographically guided core biopsy (n = 18) or sonographically guided needle localization before excision (n = 5). Microcalcifications were targeted, and specimen radiographs were obtained for each lesion, with the success of the procedure based on identifying microcalcifications on the specimen radiograph. For core biopsies, the number of cores obtained was compared with that in 49 control patients who underwent sonographically guided core biopsy of noncalcified masses. RESULTS: All 23 lesions (100%) were successfully biopsied under sonographic guidance, with microcalcifications seen on specimen radiographs in each case. Of 18 core biopsies, a mean of 8.7 cores was obtained compared with a mean of 5.5 cores in the control group (p<0.0001). Of 13 lesions sampled with core biopsy that subsequently underwent surgical excision, three (23%) were upgraded from atypical ductal hyperplasia to ductal carcinoma in situ (n = 1) and from ductal carcinoma in situ to invasive carcinoma (n = 2). Mammographically, most lesions contained more than 15 pleomorphic microcalcifications. On sonography, echogenic foci corresponded to microcalcifications in all but two cases in which broader echogenic regions were seen. When no mass or distortion was visible on mammography, sonography showed a mass or dilated ducts with internal echogenic foci. CONCLUSION: Microcalcifications identifiable on sonography can be successfully biopsied under sonographic guidance. Further study is necessary to determine whether targeting microcalcifications seen sonographically in the mass or duct can improve the rate of underestimation of disease compared with stereotactic core biopsy.