A comparative study of cytokeratin expression in Paget cells located at various sites

Extramammary Paget disease appears in anogenital, axillary, or other areas. In this study, the authors addressed the question of whether the histogenesis of 35 cases of Paget disease arising at different sites was the same.

Specimens of 35 cases of extramammary Paget disease (16 genital; 9 invasive carcinomas of genital; 6 axillary; 1 periumbilical; and 3 perianal), 4 cases of mammary Paget disease, 4 cases of breast carcinomas, and 6 cases of anal carcinomas of perianal spread from primary rectal adenocarcinomas were retrieved and stained by the avidin-biotin-complex method, using various kinds of monoclonal antikeratin antibodies.

There was no significant difference in cytokeratin expression among these cases of extramammary Paget disease. Simple epithelial keratins were expressed in Paget cells in extramammary Paget disease, but no expression of differentiation-specific or noncornifying stratified squamous epithelial keratins was observed, regardless of the degree of invasion. Paget cells in extramammary Paget disease revealed a similar cytokeratin expression to that in secretory cells of normal apocrine or eccrine glands. In addition, there was no significant difference in cytokeratin expression in tumor cells among extramammary and mammary Paget disease, breast carcinomas, and anal carcinomas.

Cases of Paget disease arising at different locations could not be distinguished from each other based on cytokeratin expression. In addition, antikeratin antibodies against simple epithelial keratins were demonstrated to be more useful for the identification of Paget cells in the paraffin sections than were conventional antibodies, such as an antibody against carcinoembryonic antigen (CEA).