Fig. 4.

Photomicrographs of H&E stained slides depicting the criteria utilized to classify tumors. a Normal mammary tissue. b Benign tumor showing proliferative disease with no cytologic atypia and minimal to no overgrowth of the epithelial or myoepithelial component (black arrows). c–e CIS lesions with overgrowth of the epithelial and/or myoepithelial component (red arrows). c Low grade CIS lesion with low grade cytologic atypia and occasional mitoses or single cell apoptosis. d Intermediate grade CIS lesion with intermediate to high grade cytologic atypia with increased mitoses (blue arrows) or single cell apoptosis. e High grade CIS lesion with intermediate to high grade cytologic atypia with tumor necrosis (yellow dashed arrow) and increased mitoses (blue arrows). f Invasive carcinoma with glands or single cells infiltrating through stroma