Figure 1

Canine mammary biopsies with columnar cell change without atypia (CCC) H&E stain. 1A Low-power view, showing dilated mammary acini in a TDLU lined with a single layer of epithelial columnar cells with underlying myoepithelial cells, many of which contain intraluminal secretions and many hyperplastic foci, 200×; 1B, 1C e 1D At higher magnification, the lining columnar cells with uniform ovoid to elongated nuclei and nucleoli absent. Many contain intraluminal secretions (1B) and show a small apical snout (1C) and intraluminal calcifications (1D), 600×.