What should you know about a lump near your armpit and breast?

The lump may be a blocked or irritated skin gland, a cyst, normal breast tissue that feels prominent, or a lymph node responding to infection or inflammation in the arm, breast, or nearby skin. A lump in this region is a presentation of breast cancer and can also be associated with lymphoma, but its presence alone cannot identify either condition.

Check for tenderness, redness, warmth, skin dimpling, nipple changes, discharge, or a difference between the two sides. Note whether it changes with your menstrual cycle, if relevant, and whether you recently had a vaccine, infection, injury, or shaving-related skin irritation. Do not squeeze it.

Arrange an appointment for a new or persistent lump, especially if it is firm, enlarging, or different from the surrounding tissue. A clinician may examine both breasts, the armpits, and nearby lymph-node areas. Imaging and, when needed, a needle sample can help identify the tissue involved. Take note of when it began and any family or personal breast history.

Seek prompt medical review for a lump that grows, becomes firm or fixed, or occurs with skin puckering, nipple inversion, bloody discharge, or swelling of the arm. Get urgent help for rapidly spreading redness with fever, severe pain, or feeling acutely unwell.

Ask whether the lump feels like breast tissue, a lymph node, or a skin lesion, and which examination or imaging is appropriate. Ask when results will be available and what change should lead you to return sooner.