Myoepithelial cells in invasive breast carcinoma: a word of caution

Prior to the era of immunohistochemistry, histopathologists used to rely almost entirely on morphological criteria in making a positive diagnosis of invasive breast carcinoma. This was the practice in histopathology departments throughout the world and has stood the test of time. However, following the invention of immunohistochemistry and in the current environment of litigation, pathologists are now more willing to use immunohistochemistry as a tool to aid them in making a confident diagnosis of invasive malignancy in the following scenarios: 1. In situations where limited amount of tissue is available allowing little room for navigation. 2. Where there is stromal fibrosis and scar tissue formation, as seen in radial scars, which can distort the architecture. 3. In well-differentiated breast tumours such as tubular and cribriform carcinomas. 4. In situations with small and irregular ductal units that may represent in-situ malignancy (ductal carcinoma in situ (DCIS)) or invasive disease. It came to our attention that the confirmation of the benign or the malignant nature of breast tumours based on the mere immunohistochemical findings for the …