Benign Mechanical Transport of Breast Epithelial Cells to Sentinel Lymph Nodes

Abstract

The evaluation of sentinel lymph nodes (SLNs) for the presence of malignant epithelial cells is essential to the staging of breast cancer patients. Recently, increased attention has focused on the possibility that epithelial cells may reach SLNs by benign mechanical means, rather than by metastasis. The purpose of this study was to test the hypothesis that pre-SLN biopsy breast massage, which we currently use to facilitate the localization of SLNs, might represent a mode of benign mechanical transport. We studied 56 patients with invasive and/or in situ ductal carcinoma and axillary SLNs with only epithelial cells and/or cell clusters (< or =0.2 mm in diameter and not associated with features of established metastases) detected predominantly in subcapsular sinuses of SLNs on hematoxylin and eosin- and/or anti-cytokeratin-stained sections. No patient had an SLN involved by either micro- or macro-metastatic carcinoma. Epithelial cells and cell clusters, < or =0.2 mm in size and without features of established metastases, occurred more frequently in the SLNs of patients who underwent pre-SLN biopsy breast massage (P < 0.001, chi2 test). The latter finding supports the hypothesis that pre-SLN biopsy breast massage is a mode of benign mechanical transport of epithelial cells to SLNs.

The clinical significance of sentinel lymph node micrometastasis in breast cancer

“…However, in a study of 89 patients, Kinoshita et al [79] have recently reported no association between preoperative FNA and the frequency of MM or survival of patients with early breast cancer. The spread of epithelial cells to axillary lymph nodes may also be attributable to benign mechanical transport [80].…”

Tumour‐positive sentinel node findings in patients with ductal carcinoma in situ

“…Apart from signs of missed invasion, these ITC or metastases detected by immunohistochemistry only may not always be real metastases, but tumour cells transported to the nodes by passive mechanisms due to preoperative breast manipulation like needle biopsy [11] or massage of the injection site of the tracer, performed in order to facilitate the transport of the mapping agent to the SN [12].…”

Papillary Lesions of the Breast: An Update

“…Moreover, breast massage in women undergoing sentinel lymph node biopsy may also cause epithelial displacement to lymph nodes. 67 In this regard, nuclear features of the epithelial cells in the lymph node may provide pertinent information with respect to benign or malignant origin, as the latter are typically larger and pleomorphic. 66 In cases of malignant-appearing epithelial cells in a lymph node, the findings of associated reactive changes, such as foamy or hemosiderin-laden macrophages and foreign body giant cell reaction, favor displaced epithelium as a potential manifestation of mechanical transport over true metastasis.…”