Apocrine CA : Lobular cancerization
Apocrine DCIS may extend into the lobules and mimic lobular carcinoma-in-situ (LCIS) as shown here. E-cadherin immunostain can be helpful in this setting. The neoplastic apocrine cells show diffuse membrane reactivity. In contrast, LCIS shows absent or fragmented staining.Apocrine DCIS may involve an area of sclerosing adenosis which may simulate an invasive carcinoma. Myoepithelial markers may be helpful in working up such cases.