12 Signs of Breast Cancer Explained

Thick Area

You may notice your skin feels thickened and/or there is an obvious lump in the breast. It can be a normal part of menstruation and breastfeeding. However, a thickening in your breast that doesn’t go away or gets bigger could also be a sign of breast cancer. The thickening can be in the skin (which is a sign of Inflammatory Breast Cancer) or deeper in the breast. This thickening is caused when cancer cells are blocking circulation in the breast (via blood or lymph vessels) or a tumor is growing near the surface of the skin. This is different from a hard lump, which is caused by cancer cells that grow very close together (see “Hard Lump”).


A dimple or indentation in the breast can happen when tight clothing leaves a temporary indent. But if a dimple in the breast doesn’t go away, it can also be a sign of breast cancer. It is caused when a tumor (lump) deep in the breast pulls the skin inward causing it to indent. Sometimes this lump can be felt, sometimes it can’t.

A dimple can be more easily seen when lifting your arms up above your head to see if the whole breast skin moves with you or not.

Nipple Crust

Crust on the nipple can be a harmless skin condition or it could be a sign of breast cancer called “Paget’s disease.” This is when cancer cells spread inside the breast and live in the nipple, creating a scab-like red or white crusted surface that can be sore and doesn’t go away.

Red or Hot

Typically this is an infection or a skin symptom common to breastfeeding or eczema. However, if antibiotics and other treatments don’t improve the symptom, it could be a sign of Inflammatory Breast Cancer. This type of cancer blocks the flow of lymph in the breast, which causes swelling and redness, but without an obvious hard lump. This may also make the breast feel warm or hot. If antibiotics don't clear up the redness after taking them for one week, then it’s best to see a breast specialist for possibly getting a “skin punch biopsy.” This is where a piece of the breast skin and the tissue immediately underneath is sampled.


Unexpected Fluid

Discharge from the nipple is common and is mostly harmless (benign). It’s usually related to developing breasts, infection, cysts, pregnancy or breastfeeding. However, if fluid is leaking from the breast outside of these changes, it is something that should be checked out.

Skin Sores

Breast cancer can sometimes build up to the point that it breaks down skin to form an open wound. Infection may cause a bad smell and/or leakage. This is usually accompanied by an obvious hard lump.


Sometimes a cancerous lump is on the surface of the breast. However, not all lumps and bumps are cancer. Many are cysts (fluid collections) or harmless, benign lumps (fibroadenomas). Many women have lumpy, bumpy breasts. However, if it’s something that concerns you, show a doctor. If other tests are inconclusive, looking at the cells from the lump under a microscope with a biopsy can help to determine if it’s cancer.

Sunken Nipple

Retracted nipples can be a normal shape of the breast (from when they were first developed). However, if you notice your nipple changing and flattening or turning inwards, it could be a sign of a new breast cancer tumor underneath, pulling the nipple toward it as it grows.


Growing Vein

This is a very rare symptom. Newly appearing blood vessels or veins are usually not a sign of cancer. More often it is connected to weight gain, breastfeeding or Mondor's disease. However, if veins become more pronounced on the skin outside of these changes, on the breast or near the collarbone (and sometimes accompanied with a swollen arm) this could be a sign of a breast cancer tumor near the surface of the skin drawing more blood to itself.

New Shape or Size

It’s common for one breast to be different in size and shape from the other. Breastfeeding can also cause changes as a result of milk production. But if one breast changes size, flattens, swells, or droops unexpectedly—and persists beyond your period—this could be a sign of breast cancer.

"Orange Peel" Skin

Called “peau d’orange,” this is when the skin of the breast looks like the dimpled skin of an orange. With peau d’orange, the breast swells causing hair follicles to look like lots of little dimples. The skin may or may not change color. This can be a sign of Inflammatory Breast Cancer. This type of cancer blocks the flow of lymph in the breast, which causes swelling and redness, but without an obvious hard lump.

Hard Lump

The most common sign of breast cancer is a lump deep in the breast. It often feels hard and immovable like a lemon seed. It can be any shape or size. A lump is not always easy to feel. If you have access to breast cancer screening, use it—a mammogram can detect a lump long before it can be felt. Most lumps turn out to be fine, such as a fluid filled cyst. But if you notice a hard lump that doesn’t come and go with your menstrual cycle, don’t ignore it. The sooner breast cancer is found, the more treatable it can be.


Note: These symptoms have been reviewed by our medical members of our advisory team (2018). The research behind the 12 signs can be explored here.

Do you know what to do if you find a symptom? Go here.