Lump on the left rib cage under the breast

The lower edge of the breast overlaps the chest wall, making it hard to tell by touch whether a finding is in breast tissue or beneath it. A swollen skin gland, cyst, bruised muscle, inflamed rib cartilage, or a normal rib contour can feel like a lump. A breast lump is a common presentation of breast cancer, but a lump alone cannot identify its cause.

Notice whether it moves with the skin, feels fixed to the chest wall, changes with your menstrual cycle, or hurts when you press or move. These details help guide examination, but they do not replace it.

Arrange a clinical appointment for a new lump that does not settle, is enlarging, or remains difficult to locate. Do not repeatedly squeeze or massage it. Record when you first noticed it, its exact position, tenderness, and any recent injury, infection, pregnancy, breastfeeding, or medicine changes.

A clinician may examine the breast, skin, ribs, and nearby lymph nodes. Depending on the findings, they may recommend imaging or another test to distinguish a breast finding from a chest-wall cause.

Seek prompt medical care if the lump comes with redness, warmth, fever, rapid swelling, severe pain, or feeling unwell. Arrange a breast assessment without delay for skin dimpling, a new nipple inversion, bloody discharge, an armpit lump, or a firm fixed change. Sudden chest pain, trouble breathing, fainting, or injury-related pain needs urgent help.

Ask whether the lump feels like breast tissue, cartilage, muscle, skin, or rib; which examination or imaging is appropriate; what changes should prompt earlier review; and when you should expect the next step.