This situation is different
from what we looked at in slide 31. Here we actually see little dermal
implants of metastatic breast cancer, not epithelial spread. These
metastases can be from anywhere, unlike the situation of Paget's disease
depicted in slide 31, where the spread is by direct continuity to the overlying
nipple skin.
Note the difference between
this slide and #31. The malignant cells are in the dermis and represent
a distant metastases, not a direct "creeping type" spread from the breast
ducts below the epidermis. This pattern is more typical of metastatic breast
cancer. Take a look for the single file arrangement and "pseudoglandular"
organization of this tumor. This pattern is highly characteristic which
makes it possible to make a very good guess as to the primary when presented
only with the metastatic tumor.