Fibrotic focus in invasive ductal carcinoma: an indicator of high tumor aggressiveness.

Histological examination of invasive ductal carcinoma of the breast often demonstrates the presence of an extensive central fibrotic focus (FF). The clinicopathological significance of the FF, or scar, in primary invasive ductal carcinoma is still ambiguous. One hundred and fifty-three cases of invasive ductal carcinoma (IDC) were classified into two groups, those with and those without FF. The differences in frequency of immunohistochemically detected overexpression of c-erbB-2 protein and nuclear accumulation of p53 protein, and the labeling index of proliferating cell nuclear antigen (PCNA), as well as histopathological parameters were compared between these two groups. IDCs smaller than 50 mm with FF showed a higher frequency of high-grade tumors, a higher frequency of lymph node metastasis, and a significantly higher frequency of c-erbB-2 protein overexpression than those without FF. In tumors of 20 mm or less, the incidence of nuclear accumulation of p53 protein was significantly higher in tumors with than those without FF. Tumors with FF showed a significantly higher PCNA labeling index than those without FF, regardless of tumor size. The present results indicate that the presence of FF is an important clinicopathological parameter associated with a higher degree of malignancy in IDCs, especially those smaller than 50 mm. Therefore, dividing IDCs into those with and those without FF appears to be meaningful clinicopathologically.