An armpit lump refers to enlargement of one or more lymph nodes under the arm.
Lumps in the armpit have various causes. Abscesses under the skin may also produce large, painful lumps in the armpit.
Lymph nodes are filters that can catch infectious organisms or cancerous tumor cells. When they do, lymph nodes increase in size and are easily felt. A breast self-examination should always include the armpit because breast cancer can enlarge the armpit lymph nodes even when the breast itself seems perfectly normal.
Lumps may occur when lymph nodes are swollen due to bacterial or viral infections, vaccinations , and cancer.
After performing a physical exam, which includes both breasts, armpits, and the neck and chest area. Additional tests may include:
Mammography to help identify the breast lump
Breast MRI to help better identify the breast lump
Breast ultrasound to show whether the lump is solid or fluid-filled
Breast biopsy, needle aspiration, or breast lump removal to remove all or part of the breast lump for closer examination by a laboratory specialist .
You do need to be concerned about any lump in the breast which includes the axilla too.