Interesting case with different interpretation.

Common things are more common. Think breast carcinoma first in breat location. It is more like a secretory carcinoma.  PAS can be positive in secretory ca. What is the size and the border of the tumor? Generally secretory ca shows well defined border, often with peripheral fibrosis. The diagnostic feature is the presence of intra- and extraceullualr rounded vacuoles giving an overall celar cell pattern.

 Thank you.

Pathologists always need to observe a entire case to make diagnosis.