Sonographic findings of pure ductal carcinoma in situ

Purpose: To investigate the characteristic sonographic (US) findings of pure ductal carcinoma in situ (DCIS) in a large series. Methods: We retrospectively reviewed the US findings of 126 cases of pure DCIS in 123 consecutive patients who underwent surgery for breast cancer in our hospital. We analyzed the US findings of the lesions according to mass or nonmass abnormality, shape, margin, orientation, echogenicity, echotexture, boundary echo, posterior acoustic features, presence of associated ductal dilatation, presence of intralesional cystic focus, and presence of microcalcifications on US. We compared the US characteristics of pure DCIS with and without mammographic microcalcifications. Results: Seventy-eight cases of pure DCIS had microcalcifications and 48 had no microcalcifications on mammography (MG). Overall, 109 cases (86.5%) of pure DCIS were demonstrated on US. DCIS with microcalcifications on MG showed positive US findings in 79.5% of cases. The most common US finding was heterogeneous hyper- or isoechoic parenchyma with intralesional microcalcifications and without posterior acoustic features. DCIS without microcalcifications on MG showed positive US findings in 97.9% of cases. The most common US findings were masses with round or oval shape, microlobulated margin, parallel orientation, heterogeneous mild hypoechogenicity, and without boundary echo or posterior acoustic features. Ductal dilatations and intralesional cystic foci were present in 17.5% (22/126) and 23.8% (30/126) of pure DCIS, respectively. Conclusions: Overall, US could demonstrate 85.7% of pure DCIS cases, including 16 (12.7%) cases of clinically and mammographically occult pure DCIS. DCIS with and without microcalcifications on MG showed different US characteristics.