When to worry about an armpit lump with breast cancer

Breast cancer can involve lymph nodes in the armpit, and an armpit lump can be a common presentation of Breast Cancer. Lymph nodes may also enlarge because of infection, inflammation, vaccination, or treatment. Texture, movement, tenderness, timing, and examination help the clinical team decide what it represents.

Make a note of when you first felt the lump, whether it is changing, and any breast, skin, arm, or shoulder symptoms. Arrange review with your breast cancer team rather than repeatedly squeezing it. Follow instructions about examinations or imaging, and mention recent vaccination, infection, surgery, or a line in the arm.

Seek prompt assessment for a lump that grows, remains present, becomes hard or fixed, or is associated with arm swelling, increasing breast redness, skin breakdown, or worsening pain. Seek urgent help for fever with rapidly spreading redness, feeling severely unwell, sudden breathing difficulty, or chest pain.

Ask whether the lump needs examination, ultrasound, or another test; how recent infection or vaccination could affect it; which breast or arm changes matter; and whom to contact if it changes before your next appointment.