Imaging and pathologic features of non-calcified ductal carcinoma in situ: can sonography predict upgrade?

Objectives: The purpose of this study was to evaluate the imaging and pathologic features and upgrade rate of non-calcified ductal carcinoma in situ (NCDCIS). The study tested the hypothesis that lesions with sonographic findings have higher upgrade rate compared to lesions seen on mammography or MRI only. Methods: This retrospective study included patients with ductal carcinoma in situ diagnosed by image-guided core breast biopsy from December 2009 to April 2018. Patients with microcalcifications on mammography or concurrent ipsilateral cancer on core biopsy were excluded. An upgrade was defined as surgical pathology showing microinvasive or invasive cancer. Results: A total of 71 lesions constituted the study cohort. Sixty two percent of cases (44/71) had a mammographic finding, and 38% (27/71) of mammographically occult lesions had findings on either ultrasound, MRI, or both. Of the 67 cases that underwent sonography, a mass was noted in 56/67 (83.6%) cases and no sonographic correlate was identified in 11/67 (16.4%) cases. Twenty-one percent (15/71) of lesions were upgraded on final surgical pathology. The upgrade rate of patients with sonographic correlate was 27% (15/56) versus with mammographic findings only was 0% (0/11). Conclusion: Ductal carcinoma in situ (DCIS) should be considered in the differential diagnosis of architectural distortion, asymmetries, focal asymmetries, and masses, even in the absence of microcalcifications. NCDCIS diagnosed by ultrasound may be an independent risk factor for upgrade. Advances in knowledge: Radiologists must be aware of imaging features of DCIS and consider increased upgrade rate when NCDCIS is diagnosed by ultrasound.