Figure 3

Microscopic examination of the invasive SDC ex PA. (A) In high power view, the ID components of SDC showed a proliferation of highly atypical epithelial cells having hyperchromatic pleomorphic nuclei and abundant eosinophilic cytoplasm, often arranged in a Roman-bridge appearance with foci of comedo necrosis (H&E stains, Original magnification × 200). Bar = 100 μm. (B) Additionally, in the PA components, the carcinoma cells occasionally displayed a minor ‘in situ’ component, characterized by malignant transformation of ductal luminal cells with possible preservation of the myoepithelial cell layer (H&E stains, Original magnification × 200). Bar = 100 μm. (C) In the ID components, the luminal adenocarcinoma cells sometimes revealed evidence of active “decapitation” secretion (H&E stains, Original magnification × 400). Bar = 50 μm. (D) In contrast, the ED components demonstrated an extensive infiltration to the adjacent pre-existing PA stroma and the extracapsular area, in a trabecular or alveolar fashion with severe vessel permeation (inset) (H&E stains, Original magnification × 200). Bar = 100 μm.