Breast US in patients with breast cancer presenting as only microcalcifications on mammography: can US differentiate ductal carcinoma in situ from invasive cancer?

PURPOSE: To retrospectively review sonographic findings of breast cancers presenting as only microcalcifications on mammography and to evaluate factors essential for differentiating ductal carcinoma in situ (DCIS) from invasive cancers.
METHODS: We retrospectively reviewed the medical records of 620 consecutive patients with confirmed breast cancer according to surgery performed between March 2008 and October 2011 at our institution. Of these, 53 lesions from 52 patients who had only microcalcifications without a mass or other associated findings on mammography were selected. Sonographic findings of microcalcification areas were analyzed and correlated with the histopathological findings.
RESULTS: Of the 53 lesions, 26 (49.18 %) were classified as invasive cancer and 27 (50.9 %) as DCIS. Ultrasonography (US) showed only echogenic calcifications in five (9.4 %), calcifications within hypoechoic parenchymal thickening in 14 (26.4 %), calcifications within ductal changes in three (5.7 %), and calcifications within a mass in 14 (26.4 %). Seventeen (32.1 %) lesions were not visible on US. Negative findings in US were more frequently observed for DCIS (n = 15, 55.6 %) than for invasive cancers (n = 2, 7.7 %) (p < 0.001). Masses (n = 11, 42.3 % of invasive cancer; n = 3, 11.1 % of DCIS; p = 0.01) were more frequently observed in invasive cancers than in DCIS.
CONCLUSIONS: US findings of breast cancers presenting as only mammographic microcalcifications were significantly different between DCIS and invasive cancers. Targeted US of microcalcifications might be helpful for predicting invasive cancers and for determining the clinical preoperative work-up, including axillary staging.