Figure 1

Histopathology of normal mammary gland, UH, ADH in woman and cat. Normal secretory mammary gland in woman (A) and cat (B): the epithelial cells are vacuolated with cytoplasmic accumulation of fat droplets. HE. Bar = 10 μm. Usual ductal hyperplasia (UH) in woman (C) and cat (D) with typical fenestrated growth pattern. The ducts are lined by monotonous luminal epithelial cells that are cuboidal to columnar, with hyperchromatic nuclei and rarely prominent nucleoli. Few myoepithelial cells are admixed in the hyperplastic epithelium. HE. Bar = 10 μm. Atypical ductal hyperplasia (ADH) in woman (E) and cat (F) with micropapillary projection of disorganized epithelial cells and spindle-shaped (myoepithelial) cells. Epithelial cells are enlarged with round nuclei with coarse chromatin and prominent single nucleoli. HE. Bar = 10 μm