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Lymph nodes are part of the lymphatic system, where white blood cells (lymphocytes) mature and ââundergo clonal multiplication. The lymphocytes are important for fighting the infection and clearing the ââviruses and bacteria from the body. Hence during any infection it is common for the lymph nodes to ââincrease in size and also become a bit tender (pain on application of pressure). â
Lymphomas are lymphoid malignancies, which present with multiple and generalized enlargement of lymph nodes all over the body, in the abdominal and chest cavity, enlarged spleen, and / or the bone marrow within the bones.
A single enlarged lymph node (as in your case) is not a indicator of such conditions. Hence you need not worry about lymphomas in your son.
The description provided indicates the possibility of the lump, being a enlarged supraclavicular lymph node, the cause of which can be infection or inflammation in the neck or surrounding area. Treatment with anti inflammatory medications like Advil and antibiotics can be prescribed to make a proper diagnosis.
Chronic Infections like tuberculosis can also present as lymphadenitis, hence tests to rule it out via a skin test or a Chest X ray can also be done. Other possible issues include bone infections.
You might consult with the treating doctors who can help answer any other doubts or questions that you might be having.