Epithelial displacement into the lymphovascular space can be seen in breast core needle biopsy specimens.

Breast core needle biopsy (BCNB) has been reported to cause mechanical epithelial displacement into adjacent tissues, leading to diagnostic difficulties. However, epithelial displacement into lymphovascular spaces (EDLS), mimicking true lymphovascular invasion, may also be seen in the initial BCNB specimen itself. We retrospectively reviewed 218 BCNB specimens diagnosed as ductal carcinoma in situ (DCIS) and searched for the presence of EDLS. The subsequent surgically resected specimens for all cases were also reviewed. EDLS was demonstrated in 7 (3.2%) of 218 initial BCNB specimens. It could be differentiated from detached clusters of DCIS cells within preexisting ducts by morphologic features and immunohistochemical stains for D2-40 and p63. EDLS can occur at initial BCNB, and, therefore, the presence of tumor cell clusters within lymphovascular spaces in a BCNB specimen with DCIS may not represent true lymphovascular invasion.