Breast, Pleomorphic lobular carcinoma in situ

The findings are of an intraductal proliferation with intermediate-to-high nuclear grade, central necrosis, and calcifications. The differential diagnosis includes ductal carcinoma in situ; however, in this case, the cells are markedly discohesive throughout the lesion. Both large-duct expansion and cancerization of lobules can be seen. In this situation, the diagnosis of pleomorphic lobular carcinoma in situ must be considered. An e-cadherin stain (not shown) was negative throughout the lesional epithelium.