Myofibroblastic reaction is a common event in metastatic disease of breast carcinoma: a descriptive study

BACKGROUND: The modification of stromal components with the disappearance of CD34 positive fibrocytes and by contrast the acquisition of smooth-muscle actin positive myofibroblasts is a frequent event in breast carcinomas but has been little studied in its metastatic sites. Therefore, the aim of the present study is to examine the stromal expression of CD34 and SMA in lymph node and liver metastases which are two of the most frequent metastatic breast cancer sites. METHODS: The distribution of CD34 fibrocytes and SMA myofibroblasts has been studied by immunohistochemistry in 41 lymph node and 36 liver metastases from patients with invasive carcinoma of no special type. RESULTS: No CD 34 fibrocytes were noted in the stroma of metastasis. By contrast, smooth-muscle actin stromal expression was observed in 95.1% of lymph node and 97.2% of liver metastases, independently of histological features of tumours. CONCLUSIONS: Myofibroblasts represent a major and constant component in the metastatic tumoral stroma of breast carcinoma highlighting that these cells could play an active role in tumour cells proliferation and spread. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_196