Ultrasonographic detection and characterization of asymptomatic ductal carcinoma in situ with histopathologic correlation

Background: Most ductal carcinoma in situ (DCIS) of the breast is asymptomatic and usually manifests as calcifications in screening mammography. On the other hand, little is known about ultrasonographic (US) features of asymptomatic DCIS, for US is rarely used for the diagnosis and evaluation of DCIS because of low sensitivity in detecting microcalcifications. Purpose: To evaluate US detection and characterization of DCIS in asymptomatic women and correlate these imaging findings with the histopathologic features. Material and Methods: This retrospective study evaluated mammographic and US images of 60 DCIS cases from 59 asymptomatic women. US was performed in knowledge of mammographic findings. The following histopathologic parameters were analyzed: Van Nuys classification, architectural pattern, and presence of microinvasion. Image detectability and US features were correlated with these histopathologic parameters. Results: Of the 54 cases (90.0%) detected on mammography, 48 cases (88.9%) had microcalcifications only, 5 (9.3%) had microcalcifications with associated density, and 1 (1.9%) had soft tissue density alone. Of the 38 cases (63.3%) identified by US, 29 cases (76.3%) had a mass with or without microcalcifications, six (15.8%) had microcalcifications only, and three (7.9%) had other findings. US identified lesions were associated with higher Van Nuys groups, microinvasion and comedocarcinoma (P = 0.044, P = 0.024, and P = 0.032, respectively). The most common US finding was a not-circumscribed, oval mass with parallel orientation and normal acoustic transmission. Microcalcifications were seen on US in 31 (81.6%) of the 38 US visible cases; this finding showed a trend of association with Van Nuys group 2 and 3 but was not statistically significant (P = 0.063). Conclusion: When DCIS was identified on US, it was associated with more aggressive histopathologic type. However, mammographic correlation is essential to differentiate benign from malignant lesion in cases seen by US; US findings of asymptomatic DCIS had a low suspicion of malignancy.