Vimentin expression in malignant versus benign breast lesions

Benign breast lesions [16 cases] and breast carcinoma [39 cases] were stained for vimentin and cytokeration in consecutive sections. Occasional vimentin staining in less than 5% of breast epithelium was considered as a variant of normal. Vimentin positivity in 5% of epithelial cells was present in one case of fibrocystic disease with moderate epitheliosis as compared to 7 cases of IDC. ILC and intraduct carcinomas were vimentin negative. Vimentin positivity was found preferentially in histologic grade III [36.4%] as compared with grade II [13.3%] and grade I [10%]. Also vimentin positive tumours were associated with increased lymph node metastases [71.4% in vimentin positive tumours versus 51.6% in vimentin negative tumours]. Although the number of vimentin positive cases was small, the extent and intensity of staining were impressive and may be of biological impact on tumour behaviour as suggested from the preferential expression of vimentin in tumours with high histologic grade and more incidence of lymph node metastases. Also the knowledge of the group of epithelial tumours expressing vimentin, with breast cancer as a recent member in this group, is of considerable importance when using vimentin as a marker of cells of mesodermal origin only