Extramammary Paget’s Disease Covered the Left Nipple and Areola

We present a case of a 71-year-old woman suffering from mammary Paget’s disease and having a 10-years history of an irregular, widespread erosion accompanied by itching and burning on the skin of her left chest, extending to the breast. The erosion had steadily enlarged and had become increasingly tender. The nipple and areola of the left breast disappeared and could not be recognized. No abnormality of the right nipple, areola, and covering skin and no supernumerary nipple were seen. Mammography and ultrasonography could not be performed because of severe pain and erosive wetness. Histopathology of a surgical biopsy specimen showed epidermal infiltration by large, round, clear atypical cells scattered individually or in small clusters and distributed horizontally throughout the epidermis. The cytoplasm of these large cells was pale and vacuolated and was equivalent to that in nipple cells in Paget’s disease, and a diagnosis of mammary Paget’s disease was made. We performed total mastectomy of the left breast with wide excision of the Paget lesion of the left chest and axillary lymph node sampling. Histological examination of the specimen showed typical distribution of Paget’s cells; however no ductal carcinoma in situ was found in the mammary ducts and invasive growth was not recognized beyond the basal membrane of the lesion. From this evidences, we established a diagnosis of large, irregulaly shaped unusual mammary Paget’s disease, not of breast cancer origin, covering the left breast, areola, and nipple.