Sonographic detection and sonographically guided biopsy of breast microcalcifications

OBJECTIVE: The purpose of this study was to evaluate the ability of sonography to depict and guide biopsies of mammographically suspicious microcalcifications and to reveal the mammographic features and histologic outcomes of lesions amenable to sonographically guided biopsy. SUBJECTS AND METHODS:. Suspicious clusters of microcalcifications without other mammographic abnormalities were evaluated on sonography before biopsy and divided into two groups: those with and those without microcalcifications seen on sonography. Sonographically detected lesions underwent sonographically guided biopsy; lesions not seen on sonography underwent mammographically guided biopsy. Imaging features and histologies were correlated, and the positive predictive value of sonography was determined. RESULTS: Of 111 lesions (105 patients), 26 lesions (23%) were identified and underwent sonographically guided biopsy; 85 lesions (77%) were not identified sonographically. The diameters of microcalcification clusters in the sonographically identified group were significantly larger (p = 0.0005) and contained larger numbers of microcalcification particles (p = 0.038) compared with clusters not identified sonographically. Sonographically identified lesions were seen as masses (77%) or dilated ducts (23%) with echogenic foci. Sonographically identified lesions were more likely to be malignant than those not seen on sonography (69% vs 21%, respectively; p < 0.00002). Of 38 malignant lesions, those visible on sonography were more likely to be invasive than those not seen on sonography (72% vs 28%, respectively; p = 0.018). In malignant lesions undergoing core biopsy and surgical excision, the extent of disease was underestimated less with sonographically guided biopsy (7%, 1/15) than with stereotactic biopsy (33%, 5/15). CONCLUSION: Suspicious microcalcifications are seen infrequently on sonography (23%) but, when detected, can be successfully biopsied with sonographic guidance and more frequently are malignant and represent invasive cancer than those seen on mammography alone.