Snapshot A 56-year-old woman presents to the physician with complaint of redness and itching in her left nipple. She says she has noticed that her areola has felt "rough and bumpy" and that there is occasional oozing of yellow pus from the skin around the nipple. Physical examination shows the finding seen in the image. The physician orders a mammogram and a punch biopsy of the skin around the nipple. Introduction Overview Paget disease of the breast is a chronic, eczematous rash on the nipple and adjacent areolar skin Epidemiology Incidence occurs in 1-4% of cases of female breast cancer underlying carcinoma is present in nearly 100% of cases almost exclusively seen in women < 2% of cases are seen in men Demographics mean age at diagnosis is 55 years ETIOLOGY Pathophysiology associated with an underlying breast adenocarcinoma extension of malignant epithelial (Paget) cells through the lactiferous ducts and ductules into the epidermis proliferation of malignant epithelial cells causes thickening of the nipple and surrounding areolar skin Presentation Symptoms erythema scaling itching and burning sensation ulceration oozing bleeding Physical exam eczematous lesion involving the nipple and areolar areas Imaging Mammography indications locate underlying breast carcinoma findings subareolar microcalcifications thickening of the nipple and areola Studies Scrape cytology rapid diagnostic screening method findings presence of malignant Paget cells Biopsy punch, wedge, or excisional biopsy of the skin lesion in the nipple and areola histologic features of Paget disease hyperkeratosis, parakeratosis, and acanthosis of the epidermis epidermal cells stain with antibodies against carcinoembryonic antigen nests of malignant Paget cells in layers of the epidermis clear cells with large, pleomorphic nuclei that spread individually into the epidermis ("pagetoid") Differential Bowen disease key distinguishing factor epidermal cells stain with antibodies to keratin and NOT to carcinoembryonic antigen Cutaneous melanoma key distinguishing factor epidermal cells stain with antibodies to S-100 and NOT to carcinoembryonic antigen Contact dermatitis key distinguishing factor onset of symptoms occurs after exposure to an irritant Treatment Surgical mastectomy and lymph node dissection indications patients with Paget disease of the breast and underlying invasive breast carcinoma Prognosis Dependent upon presence of the underlying invasive ductal carcinoma or axillary node metastases Paget disease of the breast that presents with a palpable mass is usually associated with a worse prognosis than cases without a palpable mass palpable mass and invasive ductal carcinoma: 5-year survival around 35-45% no mass and invasive ductal carcinoma: 5-year survival around 90-100%