Invasion in breast lesions: the role of the epithelial –stroma barrier

Despite the significant biological, behavioural and management differences between ductal carcinoma in situ (DCIS) and invasive carcinoma of the breast, they share many morphological and molecular similarities. Differentiation of these two different lesions in breast pathological diagnosis is based typically on the presence of an intact barrier between the malignant epithelial cells and stroma; namely, the myoepithelial cell (MEC) layer and surrounding basement membrane (BM). Despite being robust diagnostic criteria, the identification of MECs and BM to differentiate in‐situ from invasive carcinoma is not always straightforward. The MEC layer around DCIS may be interrupted and/or show an altered immunoprofile. MECs may be absent in some benign locally infiltrative lesions such as microglandular adenosis and infiltrating epitheliosis, and occasionally in non‐infiltrative conditions such as apocrine lesions, and in these contexts this does not denote malignancy or invasive disease with metastatic potential. MECs may also be absent around some malignant lesions such as some forms of papillary carcinoma, yet these behave in an indolent fashion akin to some DCIS. In Paget's disease, malignant mammary epithelial cells extend anteriorly from the ducts to infiltrate the epidermis of the nipple but do not typically infiltrate through the BM into the dermis. Conversely, BM‐like material can be seen around invasive carcinoma cells and around metastatic tumour cell deposits. Here, ...

Source: Histopathology - February 13, 2018 Category: Pathology Authors: Emad A Rakha, Islam M Miligy, Kylie L Gorringe, Michael S Toss, Andrew R Green, Stephen B Fox, Fernando C Schmitt, Puay ‐Hoon Tan, Gary M Tse, Sunil Badve, Thomas Decker, Anne Vincent‐Salomon, David J Dabbs, Maria P Foschini, Filipa Morenom, Yang Went Tags: Review Source Type: research