Ectopic Extramammary Paget's Disease of the Breast Skin: A Case Report

Whereas extramammary Paget's disease commonly occurs in the apocrine gland rich skin areas, ectopic extramammary Paget's disease develops in the skin areas that are devoid of apocrine glands. We experienced the case of a 34 year-old female patient who had a skin lesion in the upper outer quadrant of the right breast for 5 years and that lesion was diagnosed as Paget's disease according to the punch biopsy. There was no other underlying malignancy, and so wide excision was performed. The final pathologic diagnosis was Paget's disease confined to the epidermis and the size of the tumor was 3.0 x 1.1 cm. Positive staining for cytokeratin 7, epithelial membrane antigen and negative staining for S-100 protein and HMB-45 was observed on the immunohistochemical tests. We report here on an extremely unusual case of ectopic extramammary Paget's disease of the breast skin, and we include a review of the relevant literature.