Pleomorphic lobular carcinoma in situ

Lobular carcinoma in situ (LCIS) is often identified as incidental finding in breast biopsies. Pleomorphic LCIS can be associated with invasive lobular carcinoma and also occurs as an isolated lesion presenting with mammographic calcification. Histologically PLCIS may mimic DCIS but the diagnosis is facilitated by greater awareness and the use of immunohistochemistry particularly e-cadherin. It comprises large dyscohesive cells which may be associated with comedo necrosis and calcification. Apocrine and signet ring morphology can be prominent. PLCIS usually arises in a background of classical LCIS; however, the morphological and molecular features suggest that it is biologically a more aggressive disease. The lesion is associated with a significant risk of invasive carcinoma, particularly of lobular type. In its pure form, PLCIS on core biopsy is coded and managed as for DCIS.