Immunocytochemical detection of estrogen receptors in mammary Paget cells.

Immunocytochemistry was used to analyze the estrogen receptor (ER) content in mammary Paget cells obtained by scraping the nipples of six patients. The Paget cells in the smears were ER positive in four cases and ER negative in two cases. Five of the patients underwent a modified radical mastectomy; histologic study of the excision specimens showed three invasive ductal carcinomas and two intraductal carcinomas. Analysis of the ER status of the three invasive tumors, analyzed both by immunohistochemistry and by the radioligand technique, showed that the ER content in the Paget cells reflected that in the tumor in the breast parenchyma. This finding lends support to the hypothesis that Paget cells originate from an epidermotropic cancer in the parenchyma of the breast.