PLEOMORPHIC LOBULAR CARCINOMA OF THE BREAST - CLINICOPATHOLOGICAL FEATURES OF 12 CASES

Pleomorphic lobular carcinoma (PLC) of the breast was recently identif ied as a histologic variant of infiltrating lobular carcinoma (ILC) wi th a poor prognosis. Twelve cases identified from a large series of br east carcinomas were studied retrospectively. Of 11 cases with adequat e follow up, 9 were fatal This was significantly worse than either inf iltrating ductal carcinoma (IDC) or classical ILC (P less than or equa l to.002), even when stratified by axillary lymph node status. Among t he fatal cases, the median survival time was 2.1 years, significantly shorter than that for classical lobular, but not ductal, carcinoma A d istinctive pattern of in situ carcinoma, which has been described as P LC in situ, was identified in 7 of the 12 patients. This in situ compo nent was composed of tumor cells with nuclear atypia, cytologically si milar to the invasive tumor. Most PLCs lacked estrogen and progesteron e receptors and stained with BRST-2 an antibody to gross cystic diseas e fluid protein-15, suggesting the presence of apocrine differentiatio n, In summary, PLC has many of the histologic features of ILC but has anaplastic nuclei, abundant cytoplasm, and apocrine differentiation. P LC is often aneuploid, usually lacks steroid receptors, and has a sign ificantly poorer prognosis than does classical ILC.