Does HER2-positive breast cancer cause a breast lump?

HER2-positive describes a feature of certain breast cancer cells, identified through laboratory testing of breast tissue. The texture, location, or size of a lump cannot establish that result.

A breast lump may be linked to cancer, but it may also have a non-cancerous cause such as a cyst or other change in breast tissue. A clinician assesses the lump together with changes in the skin or nipple, lymph nodes, personal history, and imaging findings.

If imaging or an examination raises concern, a biopsy may be recommended. The tissue can then be examined for cancer and tested for HER2 and other features that help guide treatment. These steps answer different questions: imaging shows where a change is, while tissue testing identifies what it is.

Arrange a clinical assessment for a new, persistent, or changing lump, even if it is not painful. Note when you first noticed it, whether it changes during your menstrual cycle, and any associated nipple or skin changes.

Bring prior breast imaging reports if you have them and tell the clinician about previous breast problems, breast cancer in close relatives, pregnancy or breastfeeding, and medicines that affect your hormones. Do not try to diagnose HER2 status by checking the lump yourself.

Seek prompt medical advice for a new lump or one that is getting larger, feels fixed, or remains after your next cycle. Also arrange prompt assessment for bloody or spontaneous nipple discharge, nipple inversion that is new, dimpling, skin thickening, or a change in breast shape.

Urgent care is appropriate if the breast becomes rapidly red, hot, very swollen, or severely painful, particularly with fever or feeling unwell. These symptoms can have causes other than cancer, but they still need timely assessment.

You could ask: What tests are needed to assess this lump? If a biopsy is recommended, when will the pathology report be available? Will the tissue be tested for HER2, hormone receptors, and other features? What symptoms should lead me to contact the clinic sooner?