Paget's disease of the breast (also known as mammary Paget's disease) is a rare skin change at the nipple nearly always associated with underlying breast cancer. Paget's disease of the breast was first described by Sir James Paget in 1874. The condition is an uncommon disease accounting for 1 to 4% of all breast cancer cases.

The condition in itself often appears innocuous, limited to a surface appearance and it is sometimes dismissed, although it is actually indicative of underlying breast cancer.

Signs and symptoms

Paget's disease of the breast can affect the nipple and areola: the nipple is typically affected first and then the skin changes spread to the areola. It is common for symptoms to wax and wane. Symptoms typically only affect one breast and may include:

  • Skin: The first symptom is usually an eczema-like rash. The skin of the nipple and areola may be red, itchy, or tingly. There may be redness, oozing and crusting, and a sore that does not heal.

Pathophysiology

thumb|[[Micrograph of Paget's disease. H&E stain.|344x344px]]

Paget's disease of the breast is characterized by Paget cells: large cells with clear cytoplasm (clear halo) and eccentric (not centered), hyperchromic (darkly colored) nuclei found throughout the epidermis.

There is some controversy as to whether these cancer cells travel through the ductal system of the breast to the nipple, or whether these cells result from in situ malignant transformation.

Paget's disease of the breast is difficult to diagnose by physical exam alone due to its resemblance to dermatitis and eczema. One helpful differentiator is that eczema tends to affect the areola first, and then the nipple, whereas Paget's disease of the breast typically begins at the nipple and spreads outwards. In addition, nipple eczema is typically responsive to topical steroid application, while Paget's disease of the breast will not improve with topical steroid use. In biopsy, a tissue sample removed from the affected area is then examined under the microscope by a pathologist, who distinguishes Paget cells from other cell types by staining tissues to identify specific cells (immunohistochemistry).Chemotherapy and/or radiotherapy may also be necessary.

Patients with Paget's disease of the breast that has not spread beyond the nipple are often treated with breast-conserving surgery: removal of the cancerous area of the nipple and areola, but conservation of the rest of the breast. Patients then usually undergo radiation therapy after surgery as an adjuvant treatment to prevent recurrence.