Contributed by: Steven J. Rockoff, MD and Diana L. Lam, MD - June 1, 2020
A 63-year-old woman presents for a screening mammogram. She has a history of right breast cancer 10 years ago with treatment that included lumpectomy. The right breast is shown here:
What is the best description for the most concerning abnormality found on this exam?
A. Mass B. Architectural Distortion C. Focal Asymmetry D. Asymmetry
D. Asymmetry
Explanation: There is an asymmetry in the medial right breast which is seen only on the CC projection, with no MLO view correlate. According to the ACR BI-RADS Atlas, an asymmetry is a unilateral deposit of fibroglandular tissue that does not meet the definition of a mass and is seen on only one mammographic projection (this is in contrast to a focal asymmetry, which is seen on two projections).
There are findings related to prior lumpectomy and radiation in the posterior right breast. With the exception of a slight increase in several benign-appearing dystrophic calcifications, these post-treatment findings are stable compared to last year’s mammogram and not worrisome.
After identifying the asymmetry, what is your assessment and recommendation for this screening mammogram (assume the left breast appears normal)?
A. BI-RADS 0 (Incomplete); Recommend diagnostic mammogram and ultrasound B. BI-RADS 1 (Negative); Recommend one-year follow-up C. BI-RADS 2 (Benign); Recommend one-year follow-up D. BI-RADS 3 (Probably Benign); Recommend six-month follow-up E. BI-RADS 4 (Suspicious); Recommend biopsy
A. BI-RADS 0 (Incomplete); Recommend diagnostic mammogram and ultrasound
Explanation: The appropriate next step is a diagnostic work-up, starting with a diagnostic mammogram, and following with an ultrasound if the asymmetry persists on the spot diagnostic images. Although a new asymmetry is worrisome, there is a possibility that it represents superimposition of normal fibroglandular tissue, and so it would not be appropriate to jump straight to biopsy.
The asymmetry persisted on the diagnostic mammogram and an ultrasound looking for the abnormality in the medial half of the right breast was performed. This is a representative image from the diagnostic ultrasound. What is your assessment and recommendation?
A. BI-RADS 0 (Incomplete); Recommend MRI B. BI-RADS 3 (Probably Benign); Recommend six-month follow-up C. BI-RADS 4 (Suspicious); Recommend stereotactic biopsy D. BI-RADS 4 (Suspicious); Recommend ultrasound-guided biopsy
D. BI-RADS 4 (Suspicious); Recommend ultrasound-guided biopsy
Explanation: This irregular mass is suspicious and should be biopsied (BI-RADS 4). When a mass is visible on both ultrasound and mammogram, an ultrasound-guided biopsy is usually preferred over a stereotactic biopsy, as the former option is usually more comfortable for the patient and allows for real-time visualization of the target by the performing physician. Additionally, there may be technical challenges in performing stereotactic biopsy on a far posterior mass such as this one.
