Pre-Paget cells: Evidence of keratinocyte origin of extramammary Paget's disease

Extramammary Paget's disease (EMPD) is a carcinoma of the genital, perianal, and, rarely, axillary skin. The malignant Paget cells migrate extensively in the epidermis before invading the underlying dermis. Toker cells and keratinocytes have both been suggested as the cells of origin of EMPD. Paraffin sections of eight cases of EMPD were immunohistochemically stained for carcinoembryonic antigen, a known marker for Paget cells. The presence of carcinoembryonic antigen in some keratinocytes in all of the observed cases of EMPD suggests that EMPD originates from keratinocytes. Thus, keratinocytes containing carcinoembryonic antigen are pre-Paget cells.