Is a Breast Lump Always Cancer?

No. Most breast lumps are not cancer. Cysts, fibrous tissue changes, and other benign conditions cause the majority of lumps people find. Still, any new lump or change should be checked by a doctor, since only an exam and often imaging can tell the difference.

The American Cancer Society describes a lump more likely to be cancer as painless, hard, fixed in place, and having irregular edges, rather than smooth ones. That said, breast cancer can also show up differently. It can be soft, round, tender, or even painful. There is no feel that rules cancer in or out with certainty, which is exactly why any new or changed lump deserves a proper look rather than a guess based on how it feels.

A lump is not the only sign worth paying attention to. Skin dimpling that looks like an orange peel, a nipple that has turned inward when it did not before, and nipple discharge other than breast milk are all worth mentioning. So is swelling of the breast or under the arm, and redness, dryness, or thickening of the skin on the breast or nipple.

A cyst is a fluid-filled sac that often feels smooth and round, and it can change size with your menstrual cycle. A fibroadenoma is a firm, movable, benign growth common in younger women. Fibrocystic changes cause lumpy, sometimes tender breast tissue that fluctuates with your cycle. Most lumps found during a self-exam or a shower turn out to be one of these harmless causes.

Your doctor examines the lump and the surrounding tissue, and asks whether it changes with your cycle. A mammogram, an x-ray of the breast, is a usual first imaging test for older adults. An ultrasound is often used too, especially in younger women or dense breast tissue, since it can tell a fluid-filled cyst from a solid lump right away. If a lump looks like it needs a closer look, a core needle biopsy removes small samples of tissue using a hollow needle, usually guided by ultrasound or mammogram images. Ask your clinic when the pathology report should be back and how you will be told.

A normal mammogram is reassuring but is not perfect, especially in dense breast tissue, where lumps can be harder to see on the images. If you can feel a lump that a mammogram does not clearly explain, ask about an ultrasound or a biopsy rather than assuming the mammogram settled the question.

• Call your care team the same day if a breast turns red, hot and swollen over a few days, if the skin starts to pit like orange peel, or if discharge from the nipple is bloody.
• Call your care team within a day or two if you have found a new lump anywhere in the breast or under the arm, if a lump you already knew about has grown or hardened, or if a nipple has pulled inward when it never did before. This holds for men as well.

• Should this lump be evaluated with a mammogram, ultrasound, or both?
• Does its feel or location change how urgent this is?
• Do I need a biopsy, or can we watch it?
• When should I have my next mammogram?

• American Cancer Society — Breast Cancer Signs and Symptoms
• National Cancer Institute — Breast Cancer Treatment (PDQ)