What is Paget's disease of the nipple?

Paget's disease of the nipple is a rare form of breast cancer in which cancer cells collect in or around the nipple. The cancer usually affects the ducts of the nipple first, then spreads to the nipple surface and the areola. The nipple and areola often become scaly, red, itchy, and irritated.

Paget's disease of the nipple accounts for less than 5% of all breast cancer cases in the United States. Being aware of the symptoms is important, given that more than 97% of people with Paget's disease also have cancer elsewhere. The unusual changes in the nipple and areola are often the first indication that breast cancer is present.

Doctors are not completely sure how Paget's disease develops. One possibility is that the cancer cells start growing inside the milk ducts within the breast and then make their way out to the nipple surface. This would appear to explain why so many people with Paget's disease of the nipple have a second area of cancer within the breast. Another theory is that the cells of the nipple itself become cancerous. This theory would explain the small number of people who: only have Paget's disease in the nipple, or have a second breast cancer that appears to be completely separate from Paget's disease.

It is more common in women, but like other forms of breast cancer, it can also affect men. The disease usually develops after age 50. According to the National Cancer Institute, the average age of diagnosis in women is 62, and in men, 69.