A 71-year-old man presents to the office with itching and scaling of his left nipple. He first noticed these symptoms last month and they have increased in severity. Over-the-counter topical steroid cream provided no relief. The patient complains of irritation to the nipple when it rubs against his shirt and an increase in pruritus when he sweats. He denies any breast pain and nipple drainage. Examination reveals an ill-defined, erythematous plaque with excoriations and hemorrhagic crusting on the inferior edge of the left nipple with minimal extension into the surrounding areola.
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Paget disease of the breast, also known as mammary Paget disease (MPD), is a rare, low-grade breast malignancy.1 Comprising only 1% to 3% of breast cancers, MPD is often associated with carcinoma in situ or invasive ductal carcinomas.1,2 Though skin cancer continues to be the most common cancer, breast cancer is the second most common cancer in women.3 MPD occurs in approximately 0.4% of women in the United States.4 The peak age of incidence is 50 to 60 years and it is found more commonly in women than men.1,3
Pruritus and erythema are most often the first symptoms in patient with MPD, followed by increasing pain, burning, or bleeding of the nipple.2 Although breast cancer typically presents as a painless mass in the breast, MPD presents with small changes to the epithelial tissue such as erosions, serous drainage, or scaling.3 Due to its superficial appearance, MPD often is misdiagnosed in the early stages as a benign condition; the median duration before an accurate diagnosis is 6 to 8 months.1,3
Initially involving the nipple, erythematous plaques with increasing pruritus, pain, burning, and discharge can spread to the respective areola unilaterally despite topical treatment.5 A full-thickness punch biopsy is used to identify intraepithelial adenocarcinoma cells, or Paget cells.1,5 A bilateral mammogram is recommended to further evaluate the extent of disease.5
Treatment of MPD is based on staging of the cancer. Unlike breast cancer, the standard of care for isolated Paget disease is a mastectomy and sentinel node biopsy.1,5 Radiotherapy can be used as adjunctive therapy and is being investigated as monotherapy for cases that lack involvement of underling breast tissue.5,6
Investigations are underway to assess if breast-conserving methods result in similar survival rates compared with a mastectomy.6 Prognosis is dependent on staging of the cancer, however unfavorable outcomes are noted in patients <60 years of age, with positive lymph node involvement, invasive disease, palpable mass, or stage II disease.6
Danielle E. Johnston, PA-C, is an assistant professor for the Physician Assistant Program at Daemen College in Amherst, New York, and Rochester Institute of Technology, Rochester, New York.
1. Mayeaux EJ Jr. Paget disease of the breast. In: The Color Atlas and Synopsis of Family Medicine. 3rd ed. New York, NY: McGraw-Hill; 2009.
2. Chow C, Neuhaus IM, Grekin RC. Paget’s disease. In: Fitzpatrick’s Dermatology. 9th ed. New York, NY: McGraw Hill; 2019.
3. Giuliano AE, Hurvitz SA. Carcinoma of the female breast. In: Current Medical Diagnosis and Treatment 2020. New York, NY: McGraw-Hill; 2020.
4. SEER Breast Cancer. SEER Cancer Statistics Review 1975-2013. Cancer of the female breast (invasive). National Cancer Institute website. https://seer.cancer.gov/csr/1975_2013/results_merged/sect_04_breast.pdf. Published 2014. Accessed August 13, 2020.
5. Lloyd J, Flanagan AM. Mammary and extramammary Paget’s disease. J Clin Pathol. 2000;53(10):742-749.
6. Kawase K, Dimaio DJ, Tucker SL, et al. Paget’s disease of the breast: there is a role for breast-conserving therapy. Ann Surg Oncol. 2005;12(5):391-397.