Lymph nodes are small bean-shaped organs found throughout the body and linked by lymphatic channels. Lymph nodes are an important part of the immune system and act as “filters” which can trap foreign particles and cancer cells.
In their normal state, they are usually smaller than a pea in size, but in certain conditions, such as infections and cancers, they may become enlarged. When the lymph nodes in your neck are enlarged, you may be able to feel them as round to oval shaped swellings in your neck.
There are many reasons why the lymph nodes in the neck may become enlarged, but the two most common causes are due to infection and cancers.
Another common cause of lymph node enlargement is from cancer. The cancer may arise primarily from the lymph nodes (e.g. lymphoma), but often they have spread to the lymph nodes from somewhere else (e.g. tongue cancer, nasopharyngeal cancer).
1. Primary Malignancies
2. Secondary (Metastatic)
Malignancies These are cancers that have spread to the lymph nodes from elsewhere in the body. It is important to examine the areas from where the cancers might have spread to look for a primary cancer (e.g. oral cavity, nasopharynx, skin, scalp, ears). Common cancers that can spread to the neck lymph nodes include:
1. Viral Infections
Lymph nodes in the neck can often be enlarged as a reaction after an upper respiratory tract infection. Many viruses can cause enlargement of the lymph nodes. These include the following:
2. Bacterial infections
Lymph nodes in the neck may also be enlarged from bacterial infections. The source of the infection may not be in the neck itself but may be from the areas of lymph drainage (e.g. throat, skin, ears). It is important to examine the areas where the lymph nodes drain to look for a source of infection.
Streptococcal infections of the throat (Streptococcal Pharyngitis) can be a source of lymph node enlargement in the neck.
3. Other Infections
Other infections that can cause enlargement of the lymph nodes in the neck include tuberculosis and syphilis.
Some other less common conditions in which lymph nodes of the neck can be enlarged include:
Depending on the presentation and findings, your doctor may need to perform a thorough head and neck examination that will include:
A breast examination and abdominal examination may be also required.
Further tests may be ordered that may include:
1. Ultrasound Scan
In this scan, a probe that produces sound waves is used to create an image of your neck and its lymph nodes on a screen. This test is non-invasive, painless and does not involve any ionising radiation.
2. Computer Tomographic (CT) scans and Magnetic Resonance Imaging (MRI)
Your doctor may order a CT or MRI scan for you. These scans will usually entail you lying down on a motorised bed that will pass through a scanner to obtain an image. The CT scan uses ionising radiation to produce an image whereas an MRI scan entails the use of a strong magnetic field and radio frequency waves.
3. Fine-needle Aspiration Biopsy
Sometimes your doctor may decide if it is necessary to obtain a biopsy of an enlarged lymph node. In this test, the doctor passes a small needle through the lymph node and aspirates some cells from it for testing. The cells from the lymph nodes are smeared onto a glass side for staining and analysis by a cytologist.
At times, more tissue than obtainable from a fine-needle aspiration will be required. In these cases your doctor will schedule you to go to the operating theatre to remove a lymph node for testing. This can usually be done as a day surgery procedure and can be done under local or general anaesthesia.