Pleomorphic variant of invasive lobular carcinoma of the breast.

Infiltrating lobular carcinoma (ILC) of the classic type is well recognized; less well appreciated is a group of variant forms of ILC, which includes solid, alveolar, mixed, apocrine, signet-ring, histiocytoid, and tubulolobular variants. In addition, Page et al (Diagnostic Histopathology of the Breast, Churchill Livingstone, 1987, pp 219-226) recently have emphasized the pleomorphic variant of ILC, which demonstrates the infiltrating pattern of classic ILC; however, the nuclei are more pleomorphic and have features that may overlap with those of infiltrating duct carcinoma. To determine whether pleomorphic ILC shows significant prognostic differences from classic ILC, we reviewed the clinical courses of 25 patients with classic ILC and compared them with 16 patients with pleomorphic ILC.