Adenomegaly is the enlargement of the lymph nodes, an enlargement that can be caused by bacterial or viral infections, or linked to the presence of tumors, in particular.

When it concerns the ganglia of the mediastinum, it is a mediastinal lymphadenopathy, a cervical lymphadenopathy if the increase in volume affects the lymph nodes of the neck, or an axillary lymphadenopathy when these are the lymph nodes (another name lymph nodes) located in the armpits which are enlarged. It can also be inguinal, and affect the nodes located in the groin. Adenomegaly often results from a significant strain on the immune system, of which the lymph nodes are a key component.

Adenomegaly, what is it?

Etymologically, adenomegaly means the increase in the size of the glands: this term comes from the Greek, “adên” which means “gland” and “mega” which means large. Adenomegaly is therefore an enlargement of the lymph nodes, sometimes also called lymph nodes, following infection by a virus, bacteria or parasite, or caused by a tumor, in particular.

Lymph nodes are nodules located along lymphatic vessels in certain areas of the body:

• Lymph nodes in the mediastinum are located in the mediastinum, the middle region of the rib cage (located between the two lungs, near the heart, trachea, bronchi, and esophagus). If they are enlarged, we will speak of mediastinal lymphadenopathy.
• The cervical lymph nodes are located in the neck: when their size increases, there is cervical lymphadenopathy.
• If the adenomegaly concerns the lymph nodes located under the armpits, it is called axillary lymphadenopathy.
• Finally, when this hypertrophy affects the inguinal lymph nodes, either present in the groin, we will evoke inguinal lymphadenopathy.

How to recognize adenomegaly?

The enlarged lymph nodes are most often highlighted by the doctor during a clinical examination. It is indeed on palpation that the doctor can detect abnormal lumps in these lymph nodes.

The patient may sometimes feel on his own the appearance of a small “lump” or “mass” in the armpits, neck or groin, sometimes accompanied by fever.

Other methods may confirm the diagnosis, such as ultrasound and other types of imaging tests. In the thorax, in particular, these mediastinal lymphadenopathies will be localized using thoracic computed tomography, and the diagnosis can also be obtained, depending on their location, by mediastinoscopy (examination of the mediastinum through an endoscope), mediastinotomy (incision of the mediastinum) or thoracoscopy. Histology makes it possible, by studying the cells, to determine whether or not the lymphadenopathy is malignant.

Risk factors

Immunocompromised people are at greater risk of infections, and therefore of developing adenomegaly: patients with HIV, for example, or patients on immunosuppressive therapy. 

The infection itself is a risk factor for adenomegaly.

Causes of enlarged lymph nodes: link to their role in immunity

Lymph nodes are nodules used to filter lymph. They also play an essential role in the body’s immune response, and therefore in its defenses.

Thus, it is in these ganglia that the presentation of antigens of foreign bodies (which are infectious microorganisms, which can be bacteria, viruses or parasites), to cells of the immune system called T and B lymphocytes takes place. (i.e., white blood cells).

Following this antigenic presentation, the body’s immune response will kick in against infectious agents, or the body’s own abnormal cells (often tumors). This response involves either the production of antibodies by B lymphocytes (also called humoral immunity) or a cellular response, also called cytotoxic response, which involves CD8 T lymphocytes (a response also called cellular immunity). 

It is from this activation of the immune response within the ganglion that the hypertrophy observed in the case of adenomegaly will be explained: in fact, the number of lymphocytes (i.e. the cells of the ganglion) multiplying strongly generates the increase. the size of the lymph node. In addition, it also happens that cancer cells infiltrate the lymph node, again increasing its size. Inflammation cells can also multiply there, even the ganglion’s own immune cells, leading to cancer of the ganglia.

Benign causes

Some benign causes of enlarged lymph node size include:

• sarcoidosis (a generalized disease of the body of unknown cause);
• tuberculosis, discovered particularly following mediastinal lymphadenopathy;
• and other curable infectious diseases, such as mononucleosis caused by Epstein-Barr virus, etc.

Malignant causes

There are malignant causes, among which:

• tumors, cancers and metastases, such as Hodgkin’s or non-Hodgkin’s lymphomas, also very often diagnosed via mediastinal lymphadenopathy (following chest x-ray);
• autoimmune diseases: in particular lupus, or rheumatoid arthritis;
• more severe infections, such as that linked to the AIDS virus, HIV, or viral hepatitis, etc.

The main risks of complications of adenomegaly are, in fact, linked to its etiologies:

• In the case of tumors, the pathology can evolve into malignant tumors or even the appearance of metastases, that is to say the dissemination of cancer cells at a distance from the lymphadenopathy.
• In the case of infection with HIV, the AIDS virus, the complications are those of acquired immunodeficiency, ie an increased risk of contracting all types of infections.
• Autoimmune diseases also have an evolution with a risk of significant complications, which can cause in particular severe pain and severe disabilities.

The treatment will be that of the disease diagnosed in connection with the enlarged lymph node:

• antibiotic or antiviral treatment, or even antiparasitic, if the presence of an enlarged lymph node is due to a pathogenic agent (bacteria, virus or parasite);
• anti-cancer treatment in the case of a tumor, which may combine radiotherapy and chemotherapy;
• immunosuppressants, for example in the case of autoimmune diseases.
• Surgery, in some cases, will remove the node.

Adenomegaly is therefore a symptom that it is essential to detect as quickly as possible, and to report quickly to your attending physician: the latter can perform the clinical examination by palpation as soon as an abnormal mass is felt in cervical, axillary or inguinal regions, or detected on a control chest x-ray, for mediastinal lymphadenopathy. This healthcare professional can decide which treatment to initiate or which specialist to consult. Thus, the sooner the cause of adenomegaly is treated, the greater the chance of recovery.