Paget's disease of the nipple

Paget's disease of the nipple is a cancerous change in the skin of the nipple and areola, and behind it there is almost always a cancer inside the milk ducts. It looks harmless: the nipple turns red, flakes, itches and crusts over. That is exactly why it gets treated for months with eczema creams while time slips away. It accounts for one to four of every hundred breast cancers. Men can develop it too, but that is rare.

What is happening to the nipple

Altered cells appear inside the milk ducts. They travel up the duct to its opening and spread into the skin of the nipple, where they destroy the normal surface layer. The skin loses its protective barrier, weeps, becomes inflamed and crusts over — which is why it looks exactly like dermatitis.

The skin change is only the visible tip. In about half of women a lump can be felt behind the nipple, and in nine out of ten of those it is an invasive cancer, one that has already spread beyond the duct into surrounding breast tissue. When there is no lump, what is usually found is ductal carcinoma in situ: the cells are still inside the ducts and have gone nowhere. That form responds best to treatment, and it is the reason to move quickly on the diagnosis.

Do not confuse it with Paget's disease of bone, a completely different condition in which bone is remodelled and deformed. All they share is the name of the doctor who described both.

What the skin changes look like

The disease always starts on the nipple itself and only later spreads onto the areola — never the other way round. That is one of the key clues.

• a red, scaly patch with a sharp edge, almost always on one breast only;
• itching, burning, tingling, sometimes soreness;
• weeping, crusting and cracking; bleeding if it is scratched;
• an ulcer or raw area on the tip of the nipple that does not heal;
• discharge from the nipple, particularly blood-stained or brownish;
• the nipple pulling inwards or flattening, or changing shape;
• a lump behind the nipple or deeper in the breast;
• a swollen gland in the armpit.

One situation is worth separating out: the nipple bothers you but looks entirely normal. Itching, burning or even a spot of blood with unchanged skin usually points to something else. That still should not be ignored — blood-stained nipple discharge needs investigating in its own right.

How it differs from eczema and dermatitis

Telling it apart from skin conditions is the most important part, because getting it wrong costs months. Eczema, psoriasis, contact dermatitis from a cream or a fabric, thrush and cracked nipples during breastfeeding all look similar. The differences are real and reasonably reliable.

• Where it started. Eczema usually takes in the areola and the skin around it and often leaves the nipple itself clear. Paget's disease begins on the nipple.
• One breast or both. Dermatitis and eczema are more often on both sides, or come with patches elsewhere — in the elbow creases, behind the knees. Paget's disease is almost always one-sided.
• The edge of the patch. In Paget's disease the border is sharply drawn, as if outlined. In eczema it fades out.
• The response to treatment. This is the deciding sign. Eczema settles on a steroid cream within a week or two. Paget's disease does not settle at all, or fades slightly and returns as soon as the cream is stopped.

Hence a simple rule worth remembering: any change in the skin of one nipple that has not cleared completely after two to three weeks of treatment needs a biopsy. Not another course of cream, not a different ointment, but a sample of skin. It is the only way to settle the question.

What raises the risk

No separate causes have been identified for Paget's disease itself; it follows the same pattern as breast cancer in general.

• age: the risk rises over the years and most cases appear after fifty;
• breast or ovarian cancer in a mother, sister or daughter, especially at a young age or in several relatives;
• inherited changes in the BRCA1 and BRCA2 genes and other predisposing genes;
• a previous breast cancer;
• certain benign breast changes — not all of them, only particular types your doctor will identify from a biopsy;
• excess weight after the menopause, since fatty tissue becomes a source of oestrogen;
• drinking alcohol regularly, with the risk climbing along with the amount;
• long-term combined hormone replacement therapy;
• radiotherapy to the chest in the past, for instance for a lymphoma in early adulthood.

Age and family history cannot be changed; the rest can. A normal weight, regular activity, moderation with alcohol and stopping smoking will not remove the risk, but they lower it noticeably, and breastfeeding pushes in the same direction.

If several relatives have had breast or ovarian cancer, say so: you may need genetic counselling and follow-up on a separate schedule rather than the general one. The age at which screening starts and the intervals between scans differ from country to country, so check them against your own national programme.

Which tests make the diagnosis

Only a biopsy of the nipple skin makes the diagnosis. Under local anaesthetic a small core of skin is taken (a punch biopsy) or a wedge is removed, and it goes for histology: under the microscope the pathologist looks for the characteristic large pale cells within the epidermis. No examination, however experienced the clinician, replaces this.

Alongside that, the breast itself is searched for a tumour:

• mammography of both breasts, a low-dose X-ray;
• ultrasound of the breast and of the lymph nodes in the armpit; in younger women, and in women who are pregnant or breastfeeding, this comes first, because dense tissue shows up poorly on X-ray;
• biopsy of any lump that is found, and a needle sample from a suspicious node;
• magnetic resonance imaging of the breasts.

That last point deserves attention. A normal mammogram does not rule the diagnosis out. In Paget's disease the tumour is often small, sits directly under the nipple and does not show on the film — in roughly half of women the mammogram finds nothing. That is precisely when an MRI scan is needed: it more often shows the disease the X-ray missed, and the choice of operation depends on it. If you have been told "the mammogram is clear, so all is well" while the nipple is unchanged, that is not an answer.

Once cancer is confirmed, the tissue is tested further for oestrogen and progesterone receptors and for HER2 status. Those three results decide whether drug treatment is needed and which kind.

Surgery and how much is removed

Surgery is the foundation of treatment, and how much is removed depends on what was found inside the breast, not on the size of the patch on the skin.

Breast-conserving surgery. The nipple and areola are removed together with the tissue beneath them — this is called central excision. It is an option when there is a single focus, it is small, and it lies close to the nipple.

Mastectomy. Removing the whole breast is offered when there are several areas of disease, when the tumour is large relative to the size of the breast, when radiotherapy is not possible, or when conserving surgery would not give an acceptable result.

Checking the lymph nodes. In invasive cancer the sentinel node — the first node draining the tumour — is identified and removed during the operation. If it is clear, the remaining nodes are left alone. That spares women a full clearance of the armpit and its main consequence, persistent swelling of the arm known as lymphoedema.

Reconstruction. It can be done at the same time as a mastectomy or later on. A nipple is recreated afterwards, by tattooing, using your own tissue, or with a stick-on prosthesis. It is worth discussing before the operation, because the choice affects the technique used.

What follows the operation

Radiotherapy. After breast-conserving surgery it is given almost every time: without irradiating the remaining breast tissue the risk of the disease returning is markedly higher. After a mastectomy it is not needed by everyone and depends on the stage.

Drug treatment. It is not prescribed as a precaution but according to what the tumour tests show. With positive hormone receptors it means hormone therapy in tablet form, taken for several years. For HER2 positive tumours, targeted drugs are used. Chemotherapy is reserved for a higher risk of recurrence and is sometimes given before surgery to shrink the tumour.

Follow-up. After treatment, regular reviews continue, along with mammograms of the other, healthy breast. When the disease is caught early and confined to the ducts, the chance of complete cure is high.

When to see a doctor without delay

Paget's disease does not develop overnight, and it is not a reason to call an ambulance. But there are complaints that warrant an appointment within days rather than "when there is time":

• a change in the skin of one nipple lasting more than two to three weeks, or an ulcer that will not heal;
• blood-stained discharge, a nipple that has pulled inwards, or a new lump in the breast or armpit;
• the skin of the breast puckering or taking on an orange-peel texture;
• a breast that rapidly becomes red, swollen and hot.

The last of these is assessed the same day. It can be an abscess, particularly with a high temperature and shivering, or it can be an uncommon aggressive form, inflammatory breast cancer, which is easily mistaken for mastitis. If a woman is not breastfeeding and the picture looks like mastitis, the diagnosis has to be proved rather than assumed.

Online consultation

A remote appointment is a good way to work out where to go next. The doctor will go through what is happening to the nipple, point out the features that separate Paget's disease from eczema, explain which investigation should be arranged first, and help you read mammogram, ultrasound and histology reports you already have.

Have ready: clear photographs of the nipple in good light, taken on different days; when it started, what you have already applied and with what effect; results of any previous breast imaging; a list of your medicines, including hormonal ones; and details of breast and ovarian cancer in your relatives.

What an online appointment cannot replace is the biopsy. Nobody can tell Paget's disease from eczema on a photograph. If a nipple change is not healing, the point of a remote consultation is not to reassure you but to get you to a face-to-face assessment within a sensible time.

This material is for information only and does not replace medical advice.