Lump under the breast

The phrase under the breast can describe the breast crease, lower breast tissue, or the chest wall below it. A small bump in the skin may be an inflamed follicle or cyst. Deeper fullness may reflect normal hormonal tissue, a fluid-filled cyst, a fibroadenoma, or muscle and rib contours. A breast lump is a common presentation of breast cancer; this does not mean that a particular lump is cancerous.

Pain, movement with pressure, and changes during the menstrual cycle can provide useful clues, but they do not replace an examination. A new lump should be described by its exact position rather than only as being under the breast.

Wash the area gently and avoid squeezing, trying to drain, or repeatedly checking the bump. Write down when it appeared and whether clothing, movement, or the menstrual cycle affects it. Book an appointment if it remains, returns, grows, or feels different from the other side. The clinician can examine the skin, breast, and chest wall together and may recommend imaging based on the findings.

Arrange prompt care when the skin becomes hot or red, fever develops, pain is severe, swelling grows quickly, or there is nipple discharge, dimpling, a new nipple inversion, or an armpit lump. Seek urgent care for breathlessness, severe chest pain, or feeling faint.

Ask which structure seems to be involved, whether the lump needs imaging, how long to monitor it, and which new symptoms should bring you back sooner.