Lump on the ribs under the left breast

The lower breast and rib margin are close together. A lump that is in the skin may move with the skin, while a muscle or cartilage problem may be more noticeable with movement or pressure. Breast tissue may feel fuller at some points in the menstrual cycle. A breast lump is a common presentation of breast cancer, but location and touch cannot confirm that diagnosis.

Recent impact, strenuous activity, coughing, or an infection can also alter the chest wall. Describe these events rather than assuming they explain a lasting change.

Compare the area gently with the matching place on the other side, without repeatedly pressing it. Note whether the lump is fixed or mobile, painful or painless, and whether the skin or nipple has changed. Arrange a medical review for a new, persistent, enlarging, or unexplained lump.

The clinician may check the breast and chest wall while you move, then decide whether imaging or follow-up is useful. Bring details about injury, breastfeeding, cycle timing, and medicines.

Contact a clinician promptly if there is redness, heat, fever, increasing swelling, or worsening pain. A firm fixed area, breast skin dimpling, nipple inversion, bloody discharge, or an armpit lump requires timely breast evaluation. Call emergency services for breathing trouble, fainting, severe chest pressure, or major trauma.

Ask whether the change is in breast tissue or the chest wall, what tests could clarify it, whether pain with movement is relevant, and what symptoms should trigger an earlier appointment.