Lymph Nodes and Enlarged Lymph Nodes

Female doctor examining her patient.
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Question: What are Lymph Nodes?


Lymph nodes (also called lymph glands) are small oval structures scattered all over the body. Lymph nodes contain lymph cells, called lymphocytes. Lymphocytes grow and mature inside a lymph node, and they represent one of many types of white blood cell (WBC) that helps the body fight against infections. Lymph nodes are a part of the lymph system of the body. (See the article on the Lymph System).

Lymph nodes are connected to each other by lymph channels called the lymphatics –- small tubes (like blood vessels)-– through which lymph nodes, as well as proteins and other substances, move from one part of the body to another.

Lymph nodes in different parts of the body are named differently

When lymph nodes increase in size, they are called enlarged lymph nodes. When enlarged nodes can be felt by the doctor (in areas like the neck, armpits, and groin) they are called palpable lymph nodes.

More on Enlarged Nodes

Lymph nodes can increase in size in a number of conditions. Infections, cancer, and many immune diseases can affect lymph cells and cause an enlargement of lymph nodes.

Enlarged lymph nodes are often the first sign of lymphoma, a cancer of lymph cells. But all enlarged nodes are not lymphoma. (See the article Are Enlarged Lymph Nodes Always a Lymphoma?). Any enlarged node should be brought to the notice of a physician and investigated for the correct diagnosis.

To learn more about what causes lymph nodes to swell, see the article called Swollen Lymph Glands, and consider the memory device shown below:

What Kinds of Things Cause Swollen Lymph Nodes?

Here is an old memory device that some doctors may still recall. Hodgkin's disease is just one possibility, but it serves as the skeleton for this mnemonic. It doesn't cover everything, but it is useful for thinking about diseases associated with lymphadenopathy, or swollen lymph nodes. Generalized lymphadenopathy means there are more than two nodes involved from different areas. As you can see, there are many possible causes:

H. Hematologic: Hodgkin’s disease, leukemia, and non-Hodgkin’s lymphoma

O. Oncologic: Metastasis to lymph node, malignant melanoma

D. Dermatopathic lymphadenitis: swollen lymph nodes that drain a patch of skin that has been disrupted or irritated

G. Gaucher’s disease: a rare genetic disease

K. Kawasaki’s disease: a rare autoimmune disease involving the blood vessels and inflammation

I. Infections: bacterial, viral, and parasitic

N. Niemann–pick disease: a genetic disease that involves metabolism

S. Serum sickness: an immune response to certain medications or treatments

D. Drug reaction: response to certain drugs

I. Immunological disease: for example, rheumatoid arthritis and lupus

S. Sarcoidosis: an inflammatory disease that can affect different parts of the body

E. Endocrine: hyperthyroidism

A. Angioimmunoblastic lymphadenopathy: this is an old term; currently considered a lymphoma.

S. Systemic lupus erythematosus (lupus, or SLE)

E. Eosinophilic granulomatosis: a systemic disease involving allergic and inflammatory manifestations

Further Lymph Node Learning

In the Lymph Node Learning Hub, all different facets of lymph nodes are covered, so it’s a great place to start if you need to dive in further. If you have a question about lymph nodes, chances are we’ve got you covered here. Topics covered include lymph nodes and the immune system, painless versus painful lymph nodes, lymph nodes on x-rays and CT scans, lymph nodes in lymphadenopathy, and a bit on normal-sized lymph nodes.


Cheson BD, Fisher RI, Barrington SF et al. Recommendations for initial evaluation, staging and response assessment of Hodgkin and non-Hodgkin lymphoma: the lugano classification. J Clin Oncol. 2014;32(27)3059-3068.

Barrington SF, Mikhaeel NG, Kostakoglu L, et al. Role of imaging in the staging and response assessment of lymphoma: consensus of the international conference on malignant lymphomas imaging working group. J Clin Oncol. 2014;32(27):3048-358.

Lymphadenopathy and Malignancy. Accessed March 2015.

Mnemonics In Internal Medicine & Pediatrics. Parmar HB. B. Jain Publishers, Jan 1, 2002.

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