Breast asymmetry - interpretation pitfall

Case contributed by Dr Garth Kruger


A patient with multiple previous mammograms gets a screening mammogram in 2013.

Patient Data

Age: 65 years
Gender: Female

Another in the series of cases to illustrate management issues in breast imaging. The teaching point is illustrated if you look at one image at a time.



The small density medially deep in the breast catches the eye of the reader.

The MLO view does not contribute any information you don't already have.



The reader judges the small density is a new finding compared with the previous mammogram and recalls the patient for workup.

Do you agree?

Look carefully at the CC view of 2012 and compare it with the 2013 image above. The positioning of the newest study is better than the previous image. On the 2012 CC view there is significant rotation of the breast medially relative to the axis of the nipple. There is significant less of the retromammary fat medially compared with laterally. It is quite possible the small density is just not on the image....



The offending density is actually already visible on the 2009 CC view. The reader did not look at the 2009 study.


"Valley view" of the same patient at the time of the recall 2013.

For your information only. Very nice "valley view" image that shows the small density medially in the left breast. This is a very handy view that gives information on the medial breast tissue and at the same time gives you the contralateral tissue to compare with. Its a handy imaging tool in the larger breast especially.

The technician who did this view takes pride in his/her work: single exposure with absolutely perfect positioning and the appropriate marker close by, but not overlapping the breast.  

Case Discussion

This case illustrates how you have to interpret the images you have and at the same time consider the actual positioning of the breast to explain what you see. The medial tilt of the left breast on the CC view of 2012 is immediately obvious to the trained eye. In fact, no experienced mammography technologist would pass that image as acceptable.

If you were the reader in 2012 you would have re-done the left CC view because it is not technically acceptable. Do not be tempted to read a study that has a suboptimal image. This case proves the point.

In 2013 you would have avoided an unnecessary recall by simply looking back a couple of years. In the analog age, it was a drag to look in the dusty film bag. In the digital age, this is inexcusable.

Unnecessary recalls upset patients and their physicians and devalues the work we do. It's an inconvenience and it costs money and effort.  The recall causes significant stress for the patient and her family. Anecdotally, it seems that once a recall has been done, patients tend to miss their next screening appointment before they resume the normal screening routine. Do not miss cancers but don't recall unnecessarily.

PlayAdd to Share

Case information

rID: 21654
Published: 8th Feb 2013
Last edited: 19th Oct 2019
System: Breast
Inclusion in quiz mode: Excluded

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.