Paget’s disease of the breast

Paget's disease of the breast is a condition that causes a scaly rash on the skin of the nipple. The rash can look like eczema.

Most people who have Paget's disease also have breast cancer, so it's sometimes called a rare type of breast cancer. The breast cancer may be:

• ductal carcinoma in situ (DCIS), which is non-invasive, and the cancer cells are contained inside the milk ducts
• invasive breast cancer, which starts in the ducts or lobules of the breast and spreads into the surrounding breast tissue

Paget's disease affects about 1 to 2 out of every 100 women with breast cancer (1 to 2%).

It's most common in women aged 50 and over, but it can happen at a younger age. It can affect men, but this is very rare.

Macmillan Cancer Support has more information on what cancer is.

The first sign of Paget's disease of the breast is usually a red, scaly rash on the nipple. If you have black or brown skin, the rash can be harder to see. The skin in that area may simply look darker than your usual skin tone.

The rash can also spread to the dark skin around the nipple (the areola), often after you've had it for a few weeks. It doesn't go away, and it may become sore.

Paget's disease usually affects only 1 nipple.

Other symptoms may include:

• inflammation on the skin of the nipple and areola
• crusting, bleeding and ulcerating (becoming like an ulcer) on the skin of the nipple and areola
• thickening skin on the nipple or areola
• an itching or burning sensation in the area
• fluid (discharge) leaking from the area
• the nipple turning inwards (becoming inverted)

There may or may not be a lump in the breast. About half of women with Paget's disease (50%) have a breast lump that they can feel when they're diagnosed.

Doctors don't know what causes Paget's disease of the breast. The risk factors are similar to those for DCIS and invasive breast cancer.

Paget's disease of the breast can be mistaken for other skin conditions such as eczema, dermatitis and psoriasis, because they look alike. That makes it hard to diagnose just by looking at the skin.

There is one clue in where it starts. Paget's disease usually affects the nipple first, and after a few weeks it spreads to the areola. Other skin conditions tend to do the opposite, affecting the areola first and then the nipple.

The first thing your doctor will usually do is look at the skin changes on your nipple. Your specialist breast cancer doctor may also do some of the following tests for Paget's disease of the breast.

A skin or punch biopsy is when a doctor takes a small sample of skin from the affected nipple, along with some tissue from under the skin. The doctor first injects a local anaesthetic into the skin to numb the area. The sample is then looked at under a microscope for cancer cells.

A nipple scrape is when a doctor gently scrapes or presses cells from the skin of the affected nipple onto a glass slide. These cells are looked at under a microscope too.

A core biopsy through the nipple is when the doctor takes a core of skin from the nipple and a small piece of tissue from the breast ducts underneath. Again, a local anaesthetic is injected into the skin first to numb the area.

Along with some of these tests, you'll usually have the same tests that are done for any other type of breast cancer.

You'll usually have the following scans.

A mammogram is an x-ray of the breast.

An ultrasound uses sound waves to make a picture of the breast tissue and of the lymph nodes (glands) in the armpit.

An MRI uses magnetism to build up a detailed picture of the breast area.

The stage of a cancer tells you how big it is and how far it has spread. Your cancer doctor uses this to plan the best treatment for you.

DCIS is the earliest stage of breast cancer. At this point, some cells are changing and might go on to become breast cancer.

Invasive breast cancer is usually staged using a number system from 1 to 4.

Doctors describe breast cancer by its grade, which means how the cancer cells look when they are checked under a microscope. The grade gives an idea of how slowly or how quickly the cancer may develop.

Surgery is the main treatment for Paget's disease of the breast. The type of operation you have depends on:

• the size of the area of Paget's disease
• whether there is DCIS or invasive breast cancer
• where the affected area is in the breast

Some people have other treatments after surgery. For example, you may have radiotherapy to the breast.

What further treatment you need will depend on whether the cancer is DCIS or invasive breast cancer. Your cancer doctor or nurse will explain your treatment options in more detail.