Breast, pleomorphic lobular carcinoma in situ

Lobular carcinoma in situ (LCIS) is a pre-cancerous lesion characterized by a growth within breast glandular epithelium with a loss of e-cadherin. The pleomorphic variant of LCIS is difficult to distinguish from ductal carcinoma in situ (DCIS), because of high-grade nuclei and prominent central necrosis. Surgical management of pleomorphic LCIS is more similar to high-grade DCIS, but data are lacking. In this case, e-cadherin was negative throughout the high-grade carcinoma in situ (not shown). In addition, the cells have abundant eosinophilic cytoplasm, and ER/PgR were negative—this is also an uncommon finding, and supports apocrine differentiation.