Abstract

The stratified squamous epithelium of the nipple-areola complex may contain pale or clear cells including: Paget's disease cells (PDCs), Toker cells (TCs), and so-called clear cells (CCs). Paget's disease is an uncommon presentation of breast carcinoma. PDCs are large, atypical, have abundant, pale-staining cytoplasm that may contain mucin secretion vacuoles and bulky heterochromatic nuclei. They are commonly concentrated along the basal layer and stain for EMA, CAM5.2, cytokeratin 7, and HER2/neu oncoprotein. TCs are bland cells with roundish and scant chromatin nuclei. They are found incidentally and are reactive for EMA, CAM5.2, and cytokeratin 7, but show negativity for HER2/neu oncoprotein. So-called CCs show varied morphology, are found incidentally, and have been variably interpreted by different authors. The majority of cells that have been called epidermal CCs fit the features of pagetoid dyskeratosis. These cells are reactive for high molecular weight cytokeratin. Other CCs showing signet-ring morphology present negativity for mucins and correspond to a fixation artefact.