Allyson Louise Chesebro MD, Presenter: Nothing to Disclose

Catherine Streeto Giess MD, Abstract Co-Author: Nothing to Disclose

Nicole S. Winkler MD, Abstract Co-Author: Nothing to Disclose

Robyn L. Birdwell MD, Abstract Co-Author: Nothing to Disclose

To determine outcomes for developing asymmetries on diagnostic mammograms and the impact of correlative ultrasound (US) and breast magnetic resonance imaging (MRI) on clinical management.

IRB approved, retrospective review of our mammography database from 1/1/2009 to 12/31/2012 identified 2354 diagnostic mammograms classified as “focal asymmetry”, 521 with prior studies and prospectively classified as BIRADS 0, 3, 4, or 5. Retrospective image review of these 521 studies identified 202 developing lesions that met the BIRADS definition of asymmetry (one view) or focal asymmetry (two view), henceforth collectively “developing asymmetries”. Patient demographics, correlative US and MRI, and outcomes were obtained from the longitudinal medical record.

Mean patient age was 56 years (range 31-82). 187/202 (92.6%) had targeted US with 75 correlates, 3 equivocal correlates, and 109 without correlate. BIRADS assessment after diagnostic mammography included 21 BIRADS 0, 121 BIRADS 3, and 60 BIRADS 4 or 5. 69/202 (34.2%) had breast MRI, including all 21 BIRADS 0, 40 BIRADS 3 (33 for index lesion, 7 for other indications) and 8 BIRADS 4 or 5 lesions. An MRI correlate was present in 28/69 (40.6%) lesions. Biopsy was performed in 73 (36.1%) of 202 lesions, 31 (42.5%) malignant and 42 (57.5%) benign. Thirteen malignancies received BIRADS 3 (N=12) or BIRADS 0 (N=1) assessment on diagnostic mammography; an US correlate was absent in 10, present in 2, and US was not performed in 1. Eight (61.5%) of these 13 malignancies had MRI, 6 at diagnostic evaluation and 2 at 2-6 month follow up, all resulting in BIRADS 4 upgrade. The other 5 were diagnosed 1-12 months later. Malignancies included 14 IDC, 8 ILC, 5 mixed IDC/ILC, 4 DCIS. Of 129 non-biopsied lesions, 80 (62.0%) were stable for ≥ 24 months, 39 (30.2%) had < 24 months follow-up, and 10 (7.8%) were lost to follow up.

Developing asymmetries were malignant in 15.3% cases and often lacked an US correlate. Diagnostic breast MRI can guide BIRADS assessment for developing asymmetries considered incomplete or probably benign after diagnostic mammography. Cancers with lobular pathology represented nearly half of malignancies.

Developing asymmetries on mammography should be viewed with suspicion, despite lack of an US correlate. Diagnostic breast MRI can help guide assessment and management.

Chesebro, A, Giess, C, Winkler, N, Birdwell, R, Developing Asymmetry on Mammography: Histopathologic Findings and Effect of Correlative MRI and US on Management.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14001539.html