Ductal Carcinoma in Situ Cell atypia -> abnormal cell appearance. Differentiation Well differentiated -> low grade DCIS Grade 1 Moderate differentiation -> grade 2 Falls between well differentiated and poorly differentiated. Poorly differentiated -> grade 3 Cells significantly different to normal breast cells. Necrosis within ducts. Vary in size. Important to clear margins in surgical resection Hormone receptor status Determine if express estrogen and progesterone receptors. Determine HER2 status Determine Ki-67 index Measures cell growth rate -> proliferation index High index -> aggressive disease Lymph vascular invasion and perineural invasion Evaluate whether tumor cells invade blood or lymph vessels or nerve fibres. Lobular Carcinoma in Situ Cells are uniform and slightly larger than normal breast cells indistinctive cell borders Small uniform nuclei Evenly disturbed chromatin Inconspicuous nuclei Loss of cellular cohesion due to dysfunctional E-cadherin catenin axis HALLMARK FEATURE Itself not considered a cancer but is an important risk factor for developing invasive cancer. Mammograms DCIS is seen on mammograms. Macrocalcifications or areas of abnormal density within the ducts. Calcium depositions. LCIS Calcifications not usually seen. May appear as a subtle soft-tissue opacity without distinctive calcifications. Usually there is a bilateral involvement simultaneous