Lifestyle

A New Lump Near the Breast or Armpit Can Be a Sign of Breast Cancer. Other Signs to Know

By Erica Coleman · November 8, 2026

A lump found in the shower. A patch of skin that suddenly looks different. A small change in the nipple that seems easy to explain away. Some of these changes are on the short list of signs that MedlinePlus, the consumer health service of the National Library of Medicine, says can point to breast cancer.

MedlinePlus describes breast cancer as a cancer that starts in breast tissue. It happens when cells in the breast change and grow out of control, and those extra cells can form a mass called a tumor. MedlinePlus calls it the second most common type of cancer in women in the United States, and it notes that, rarely, it can also affect men.

Age matters here. Older age is the first item on the MedlinePlus list of factors that raise the risk. Others on that list include a history of breast cancer or benign breast disease, inherited gene changes such as BRCA1 and BRCA2, dense breast tissue, radiation therapy to the breast or chest, obesity, and drinking alcohol.

These are the signs and symptoms MedlinePlus lists.

A new lump or thickening. MedlinePlus puts this first: a new lump or thickening in or near the breast or in the armpit. The armpit part is easy to forget, so it is worth knowing that a change there belongs on the same list.

A change in size or shape. A breast that looks or feels different in size or shape than it did before is listed as a sign.

Dimpling or puckering of the skin. MedlinePlus says the skin of the breast may dimple or pucker, and that it may look like the skin of an orange.

A nipple that turns inward. The page lists a nipple turned inward into the breast.

Nipple discharge other than breast milk. MedlinePlus adds three details that are worth reading slowly. The discharge might happen suddenly, it might be bloody, or it might happen in only one breast.

Scaly, red, or swollen skin. This can show up in the nipple area or on the breast itself.

Pain in any area of the breast. MedlinePlus includes breast pain on the same list of signs.

Having one of these changes does not mean someone has cancer. It means the change deserves a look from a professional who can examine it. MedlinePlus explains that a provider may use several tools to find out what is going on, including a physical exam with a clinical breast exam that checks the breasts and armpits for lumps or anything unusual, a medical history, imaging tests such as a mammogram, an ultrasound, or an MRI, and a breast biopsy.

If cancer is found, more tests help the care team decide on the best treatment, and staging tests show whether it has spread. MedlinePlus lists treatments that include surgery, radiation therapy, chemotherapy, hormone therapy, targeted therapy, and immunotherapy.

MedlinePlus also points to regular mammograms, which it says may be able to identify breast cancer in the early stages, when it is easier to treat. A screening schedule is a separate conversation from a new symptom, though. If you notice a change, there is no reason to wait for your next routine appointment to bring it up.

The practical step is simple. Note what you noticed and when it started, whether it is on one side or both, and whether it has changed. Then call your doctor or another health care provider and ask to be seen. Only a clinician can sort out what a breast change means after an exam and any tests they order.

This article is for general information and is not medical advice. Talk with your doctor or health care provider about any new or changing breast symptoms. This article was produced with the assistance of AI and fact-checked against the sources cited by LightWave Reports.