Fig. 3

Pathologic findings. (a) Results of 14-G core needle biopsy. Tumor cells with densely stained nuclear chromatin show papillary growth in the mammary ducts. The glandular epithelium has few lining myoepithelial cells. A few myoepithelial cells show positivity for p63. CK5/6 is negative in proliferating glandular epithelium (positive cells are myoepithelial cells). The diagnosis is DCIS. (b) Macroscopic appearance (top) and microscopic appearance (bottom). Loupe image (bottom left) and high magnification image of the lesion within it (bottom right). Postoperative histopathological diagnosis reveals that atypical cells have proliferated within the duct to a diameter of 1.7 mm, leading to the diagnosis of low-grade DCIS. Arrow in macroscopic appearance: site at which non-invasive cancer is confirmed