Pagets disease of the breast is a type of cancer that outwardly may have the appearance of eczema, with skin changes involving the nipple of the breast. The condition is an uncommon disease accounting for 1 to 4.3% of all breast cancers and was first described by Sir James Paget in 1874. The condition in itself often appears innocuous, limited to a surface appearance and it is sometimes dismissed, although actually indicative of underlying breast cancer. Immunohistochemistry of Paget cells and underlying breast cancer show a more aggressive, HER2-enriched, molecular subtype of breast cancer. Signs and symptoms
Pagets disease of the breast can affect the nipple and areola. Symptoms typically only affect one breast. Symptoms may include:

Skin. The first symptom is usually an eczema-like rash. The skin of the nipple and areola may be red, itchy and inflamed. After a period of time, the skin may become flaky or scaly. Discharge. A discharge, which may be straw-colored or bloody, may ooze from the area. Sensation. Some women have a burning sensation. These symptoms usually occur in more advanced stages, when serious destruction of the skin often prompts the patient to consult. Lumps or masses in the breast occur in 50% of the patients. In more advanced stages, the disease may cause tingling, increased sensitivity and pain. Nipple changes. The nipple may become inverted. Breast changes.
There may or may not be a lump in the breast, and there may be redness, oozing and crusting, and a sore that does not heal.The symptoms usually affect the nipple and then spread to the areola and then the breast. It is common for the symptoms to wax and wane. Most women do not visit the doctor because they assume Pagets disease to be minor contact dermatitis or eczema. A lump or skin irritation that does not seem to heal for over a month indicates that attention by a specialist is needed. Pathophysiology
Pagets disease of the breast is characterised by Paget cells. Paget cells are large cells with clear cytoplasm (clear halo) and eccentric, hyperchromic nuclei found throughout the epidermis.There is some controversy as to whether these cells arise from the ductal system of the breast, or whether these cells are a result of in situ malignant transformation.According to the migratory theory, ductal carcinoma in situ cells migrate into the lactiferous sinuses and the nipple skin. Cancer cells disrupt the normal epithelial barrier and extracellular fluid accumulates on the surface of the skin, resulting in the crusting of the areola skin. Diagnosis
Recommended tests are a mammogram and a biopsy to confirm the diagnosis, and cytopathology may also be helpful. Pagets disease is difficult to diagnose due to its resemblance to dermatitis and eczema; even in patients after ductal carcinoma in situ surgery. Eczema tends to affect the areola first, and then the nipple, whereas Pagets spreads from the nipple.