Seven-year survey of classical and pleomorphic invasive lobular breast carcinomas in women from southeastern Serbia: Differences in clinicopathological and immunohistochemical features.

Purpose: The occurrence of different variants of invasive lobular carcinoma (ILC) of the breast is variable. For example, the pleomorphic variant of ILC has an incidence of around 5%; however, the number of analyzed cases of ILC is shadowed by the number of ductal type carcinoma (IDC). Thus, we aimed to analyze the classical and pleomorphic ILCs in women from southeastern Serbia.

Methods: Analyzed were 296 cases (11.91%) diagnosed with ILC, out of 2486 cases of all breast cancers (BCs), during a 7-year period (2005-2011) from southeastern Serbia. The differences in clinicopathological and immunohistochemical features (estrogen receptor/ER, progesterone receptor/ PR, HER-2, Ki-67, BRCA-1, p53 and E-cadherin) of these cases of ILCs were assessed and compared.

Results: Pleomorphic ILC occurred relatively rarely compared to other variants, however almost one fifth of the ILC cases were pleomorphic. No statistically significant correlation was found between patient age, tumor stage and the presence/absence of multifocality (MFC), multicentricity (MCC) and bilaterality (BL) on one side, and ILC variant on the other. Only the expression of two prognostic and predictive immunohistochemical markers, important for endocrine therapy, ER and PR, showed significant correlation with the ILC variant.

Conclusions: Although higher tumor stage, incidence of multicentricity, overexpression of HER2 and higher p53 positivity were deemed to be characteristic of pleomorphic ILC, in our study that included a much larger number of cases than previous studies did, such correlations were not observed. Thus, it appears that the only two features of pleomorphic ILCs is absence of ER and PR positivity.