What Is Paget Disease of the Breast?

This form of breast cancer is often mistaken for skin conditions such as dermatitis or eczema.

Paget disease of the breast (also known as Paget disease of the nipple, or mammary Paget disease) is a form of breast cancer that's present in about one percent of all breast cancer cases, according to the American Cancer Society.

The disease starts in the breast ducts and spreads to the skin of the nipple, then to the areola (dark circle around the nipple).

Paget disease is frequently misdiagnosed at first, because its early symptoms can easily be confused with those of more common skin conditions affecting the nipple.

This disease is not related to Paget's disease of the bone, which is a metabolic bone disease.

Paget disease of the breast mainly affects women over 50, notes the American Cancer Society.

Causes

While it's not known exactly what causes Paget disease of the breast, the following two theories are most widely believed to explain its onset:

• Cancer cells from a tumor inside the breast move through the milk ducts to the nipple and areola. This theory may account for why Paget disease of the breast is almost always found together with tumors inside the same breast.
• Cells in the nipple or areola become cancerous on their own.

Symptoms of Paget Disease

The signs and symptoms of Paget disease of the breast are often mistaken for those of skin conditions such as dermatitis or eczema, which are far more common.

Skin changes may come and go early on, or respond to topical treatment, making it seem like your skin is healing.

Most women experience symptoms for several months before getting a diagnosis of Paget disease.

Signs and symptoms usually occur in one breast only. The disease typically starts in the nipple and may spread to the areola and other areas of the breast.

Possible symptoms of Paget disease include:

• Flaky or scaly skin on the nipple
• Crusty, oozing, or hardened skin that looks like eczema on the nipple or areola
• Burning, itching, or tingling in the nipple area
• Redness in the nipple area
• Straw-colored or bloody nipple discharge
• Flattened or turned-in nipple
• A lump in the breast

Diagnosis of Paget Disease

According to the National Cancer Institute, about 50 percent of people with Paget disease of the breast have a breast lump that can be felt during a breast exam given by their doctor.

Your doctor may perform the following procedures to diagnosis the disease:

Clinical breast exam: Your doctor will look and feel for lumps or unusual areas in both breasts, including the outer skin and nipples.

Mammogram and MRI: A mammogram is an X-ray of your breast tissue that can detect lumps within the breast. If neither breast shows any signs of breast cancer in a mammogram, your doctor may recommend magnetic resonance imaging (MRI), which can detect cancer that a mammogram may not.

Breast biopsy: Your doctor will take a small sample of any lump in the breast and send it to a lab for analysis.

Nipple biopsy: Your doctor or breast surgeon will take a sample of tissue from the skin of your nipple and, if possible, collect a sample of nipple discharge to send to a lab.

Sentinel lymph node biopsy: If imaging or a biopsy show invasive breast cancer, your doctor will want to see if the cancer has spread to the lymph nodes under your arms. If no cancer is found in a tissue sample from the sentinel node, it is unlikely the cancer has spread to any other nodes.

Treatment of Paget Disease

Depending on your condition, you may need one or more of the following treatments:

Simple mastectomy: This procedure removes your entire breast. The lymph nodes in your armpit are not removed if they are cancer-free.

Lumpectomy: This procedure removes only the area of your breast that has cancer, as well as your nipple and areola. Radiation therapy is usually required after a lumpectomy.

Adjuvant therapy: This describes any number of treatments to prevent a recurrence of cancer after surgery, including chemotherapy, radiation, and hormone therapy.