Management of Breast Asymmetry Seen Only on CC View
When a radiologist reports asymmetry better visualized on the CC view without specifying whether it's focal, developing, or global, the next step is diagnostic mammography with spot compression views (with and without magnification) to determine if the asymmetry persists or represents summation artifact, followed by targeted ultrasound of the area. 1
Immediate Diagnostic Workup
The incomplete characterization of the asymmetry warrants a BI-RADS Category 0 assessment (need additional imaging evaluation), as the finding requires further evaluation to make a final assessment 2. The standard approach includes:
- Spot compression views are essential to determine whether the asymmetry persists or disappears (indicating summation artifact from overlapping normal breast tissue) 2, 1
- Magnification views should be added if any associated microcalcifications are identified, as these help characterize calcifications that may indicate malignancy 1
- Targeted ultrasound of the specific area of concern must be performed concurrently to identify potentially benign causes and provide a target for biopsy if indicated 1
Why This Matters Clinically
The lack of specification about asymmetry type is clinically significant because developing asymmetry carries a positive predictive value of 12.8% for cancer at screening and 42.9% when biopsy is recommended 1. Critically, 23.8% of cancers presenting as developing asymmetry had no sonographic correlate, meaning mammographic evaluation cannot be skipped even if ultrasound is negative 1.
Simple asymmetry without temporal change or associated findings has lower malignancy risk, but both DCIS and invasive carcinomas can manifest as asymmetries without calcifications 1. Therefore, the absence of calcifications does not exclude malignancy 1.
Subsequent Management Based on Findings
If Asymmetry Persists on Spot Compression:
- BI-RADS 4-5 assessment (suspicious features such as architectural distortion, associated microcalcifications, or correlation with palpable abnormality): Proceed directly to image-guided core needle biopsy 2, 1
- BI-RADS 3 assessment (probably benign features): Clinical re-examination in 3-6 months with follow-up imaging every 6-12 months for 1-2 years to assess stability 1
- BI-RADS 1-2 assessment (asymmetry resolves or clearly benign): Return to routine screening 1
If Asymmetry Disappears on Spot Compression:
This indicates summation artifact from normal overlapping tissue, which is benign and requires no further workup 3, 4.
Critical Pitfall to Avoid
Do not assign BI-RADS 3 (probably benign) or recommend short-interval follow-up during the initial screening interpretation. All published studies emphasize the need to conduct a complete diagnostic imaging evaluation before making a probably benign assessment 2. The radiologist must complete the diagnostic workup with additional views and ultrasound before determining the appropriate BI-RADS category 1.