What it means
Radiologists compare the left and right breasts, which usually look much alike. A focal asymmetry is a small area of denser tissue in one breast, seen on two different views, with no matching area on the other side. It lacks the rounded, outward-bulging edges of a true mass. Most often it is simply a normal patch of breast tissue, or layers of tissue overlapping on the image.
When it matters
Most focal asymmetries are benign. If one shows up on a screening mammogram, you may be called back for extra views, such as a spot compression view that presses on just that area, and often an ultrasound. Older mammograms help a lot: an area that has looked the same for years is reassuring. A new or growing area, called a developing asymmetry, gets a closer look and may lead to a biopsy.
Questions to ask your doctor
- Is this area new, or was it on my earlier mammograms?
- Did the extra views or ultrasound show anything behind it?
- What BI-RADS category is it, and what follow-up is advised?
