By Michael Misialek, M.D.
Reading the pathology request on my next patient, I saw she was a 55-year-old with an abnormality on her mammogram. Upon further investigation I discovered she had dense breasts and a concerning “radiographic opacity.” The suspicion of cancer was high based on these findings and so, a breast biopsy had been recommended. As I placed the slide on my microscope and brought the tissues into focus, I immediately recognized the patterns of an invasive cancer. Unfortunately the suspicion had proven correct.
Just a few patients earlier, an almost identical history had prompted another breast biopsy. This time the results were far different, a benign finding and obviously a sense of relief for the woman. Every day these stories unfold; the never ending workup of abnormal mammogram findings. Both radiographically and microscopically, it can be challenging at times sorting out these diagnoses, particularly in the face of dense breasts.
But what, exactly, are dense breasts and why are they suddenly in the news?
Breast Tissue 101
Breast tissue is actually made up of three tissue types when viewed under the microscope. The percentage of each varies between patients. There is fat, fibrous tissue (the supporting framework) and glandular tissue (the functional component). This is what I actually see under the microscope. Cancer can occur in fatty or dense breasts. It can be toughest to assess when the background is dense.
Biopsy, considered the gold standard in diagnosis, may even prove difficult to interpret when in the background of dense breasts. Dense breasts can hide a cancer, making it more difficult to detect both by mammogram and under the microscope.
Breast density has taken a lot of heat recently. A new study published in the Annals of Internal Medicine found that not all women with dense breasts and a normal mammogram warranted additional screening, as was previously thought. Understandably this report has received much attention. The authors found nearly half of all women had dense breasts. This alone should not be the sole criterion by which additional imaging tests are ordered since these women do not all go on to have a cancer. Clearly other risk factors are at play.
Confusion All Around
This is confusing for patients and doctors alike, especially when it seems as if screening guidelines are a moving target. Recently, the American College of Physicians issued new cancer screening guidelines: among these was mammograms, being recommended every two years. This too is getting a lot of press.
The American College of Radiology, American Cancer Society, Society of Breast Imaging and American College of Obstetricians and Gynecologists recommend yearly mammograms beginning at age 40. Continue reading