On biopsy, an infiltrating lobular carcinoma was demonstrated

We breast imagers sometimes miss the lobular carcinomas because they do not present mammographically like IDC. They rarely show calcification and they don't generally develop the density and spiculation we associate with IDC on mammograms.

Always compare with previous studies. Be aware of these lesions and the fact they may appear as very subtle developing densities on mammography. Be wary and attentive of any post-menopausal lady developing unexplained densities on mammography. Lastly, use a high index of suspicion.

Lastly: personally, I am looking forward to see what molecular breast imaging (MBI) is going to do in the diagnosis of these lesions.