Breast Cancer 101

Enlarged Axillary Lymph Nodes: What to Know

Breast Cancer 101 Rare Breast Cancer Types Enlarged Axillary Lymph Nodes: What to Know

Enlarged Axillary Lymph Nodes Information

Enlarged axillary lymph nodes can be a symptom of a serious medical condition, including breast cancer. If you, or a loved one, notice swelling and/or feel a solid mass in the armpit area please contact a medical professional.

The Lymphatic System

The human circulatory system comprises the cardiovascular and lymphatic systems, two networks that play complementary roles. As you may remember from high school biology, the cardiovascular system consists of arteries and veins. Arteries transfer oxygen- and nutrient-rich blood to cells, while veins return blood carrying carbon dioxide back to the lungs.

The lymphatic system, a nearly parallel structure, plays a critical role in the body's immune system. It moves lymph between tissue and the bloodstream via lymph ducts, lymph nodes, lymph vessels, and organs, including adenoids, the spleen, the thymus, and tonsils.

  • Lymph: a clear-to-white fluid made up of white blood cells that attack bacteria found in the bloodstream. Lymph can also be found in the intestines (chyle), where they hold proteins and fats.
  • Lymph Nodes (Lymph Glands): are found throughout the human body (behind breast tissue, arm tissue, leg tissue, etc.) and are linked together through lymphatic vessels. Lymph nodes screen and/or remove foreign substances (for example, substances secreted from bacteria, called antigens).

If the lymph nodes detect an unrecognizable substance they will create an antibody, which flows in blood circulation to target and destroy the foreign material in cells throughout the body.

Swollen lymph nodes indicate they are producing infection-fighting white blood cells to combat a recognized threat to the body. The threat can range from relatively trivial issues like a cold or throat infection to more serious conditions like cancer. Understanding the health of the lymphatic system is crucial in diagnosing, prognosticating, and treating cancer tumors.

Enlarged Axillary Lymph Nodes

The axillary (armpit) lymph nodes filter and/or trap lymph from the arm, chest wall, and breast. It is often challenging to feel normal axillary lymph nodes. Not all enlarged axillary lymph nodes feel the same, and it is essential to note that enlarged axillary lymph nodes are not necessarily a sign of cancer. However, we strongly advise you to consult with a medical provider if you are concerned about enlarged axillary lymph nodes.

Enlarged axillary lymph nodes may stem from various causes. If a patient does not have cancer, some local, non-cancerous causes of enlarged axillary lymph nodes include:

  • An injury to the armpit, arm or hand (almost always non-cancerous).
  • Localized infection or hydradenitits.
  • Brucellois (also known as Undulant fever, Malta fever and/or Mediterranean fever): a bacteria disease picked up from contact with dogs, cows, goats, pigs or other mammals. Brucellois can be contracted consuming unpasteurized dairy products.
  • Cat Scratch Disease: cats infected with bartonellahenselae can transfer the bacteria to humans by piercing their skin (bite or scratch). The illness may result in fatigue, a fever, headache(s) and a loss of appetite. Most of the time the body can expunge the infection without medical treatment.
  • Silicone breast implants: a reaction by the lymphatic system to the placement of a foreign substance (including the small possibility of a silicone leak).

Systematic, non-cancerous causes of enlarged axillary lymph nodes include:

  • Viral infections: mononucleosis, chicken pox, measles, HIV/AIDS and others.
  • Bacterial: tuberculosis, etc.
  • Fungal.
  • Temporary side effects from a vaccination.

Enlarged axillary lymph nodes can be a symptom of the following local or metastasized (systematic) cancer maladies:

  • A tumor in or near the axillary lymph node.
  • Leukemia.
  • Hodgkin’s Lymphoma.
  • Non-Hodgkin’s Lymphoma.
  • Melanoma.

Enlarged Axillary Lymph Nodes and Breast Cancer

Approximately 75 percent of lymph found in the breasts drains into the axillary lymph nodes. As such, detecting enlarged axillary lymph nodes, especially those that are hard to the touch, plays a crucial role in diagnosing and staging breast cancer.

Not all breast cancer cases result in enlarged axillary lymph nodes. However, the presence of enlarged axillary lymph nodes strongly indicates that breast cancer may be at a more advanced stage. Doctors consider three central determinants when evaluating the stage of a breast cancer tumor: the detection of cancer in the lymph nodes, the size of the breast cancer tumor, and whether it has spread to other areas of the body.

There are five categories to describe the involvement of breast cancer in the axillary lymph nodes:

  • NX: lymph nodes cannot be clinically evaluated.
  • N0: no identifiable cancer in the axillary lymph nodes.
  • N1: cancer is present in the axillary lymph nodes. However, it is not attached to the chest wall or between different axillary lymph nodes.
  • N2: cancer is identified in the axillary lymph nodes. The cancer has linked between different axillary lymph nodes and/or the chest wall.
  • N3: in addition to N2, cancer has spread above and below the collarbone.

To determine the axillary lymph node status, a sentinel node biopsy may be performed. This surgical technique involves injecting a radioactive blue dye into the site of the breast cancer tumor, helping surgeons identify the closest lymph nodes to the cancer site.

  • The axillary lymph nodes nearest to the breast cancer site are removed and biopsied for cancer.
  • If cancer is not detected the remaining axillary lymph nodes are not removed.
  • If cancer is detected additional axillary lymph nodes are removed and biopsied.



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