Flat epithelia atypia occurs when abnormal-looking (or “atypical”) cells line up in columns along the insides of the terminal duct lobular unit. This is where the breast’s milk-producing lobules join with the smaller ducts that will carry milk to the main duct. The lobule and branching ducts often enlarge as a result of this cell buildup. (If the cells have a normal appearance, the condition is called columnar cell lesions.)
Different doctors may approach the condition differently: some might remove it, others might not. Also, researchers are still working to understand if there’s a connection between flat epithelial atypia and breast cancer. In some cases, flat epithelial atypia is found close to other atypical breast changes, such as atypical ductal hyperplasia, low-grade ductal carcinoma in situ, and/or tubular carcinoma. This suggests that it might be a precursor to early breast cancer. However, some studies have found that flat epithelial atypia actually poses a low risk of developing into invasive breast cancer. More research is needed to better understand the significance of this condition.
If you’re diagnosed with flat epithelial atypia, talk to your doctor about what this means for you. You can ask if any other atypical breast changes were found. You also may wish to seek a second opinion from another pathologist to be sure that nothing was missed. Generally, if no other changes were found along with the flat epithelial atypia, you can continue with routine breast cancer screenings.