There are many causes of swollen lymph nodes in the neck, which can be caused by infections, tumours, reactive hyperplasia and histiocytic hyperplasia.
1. Inflammatory enlargement: Lymph nodes can become congested and oedematous when acute and chronic lymph node infections are caused by bacteria, viruses, rickettsia, chlamydia, fungi, spirochetes, protozoa and helminths, and lymphocytes and macrophages can proliferate, manifesting as enlarged lymph nodes.
2.Neoplastic enlargement: tumours of lymphatic tissue origin such as lymphoma, lymphocytic leukaemia and tumours metastasised to lymph nodes (e.g. oral cancer metastasised to cervical lymph nodes, nasopharyngeal cancer metastasised to cervical lymph nodes, gastric cancer metastasised to left supraclavicular lymph nodes, etc.) are caused by excessive proliferation of tumour cells in the lymph nodes, and can lead to increased inflammatory cells and proliferation of fibrous tissue in the lymph nodes, resulting in enlarged lymph nodes.
3. Reactive hyperplasia enlargement: including non-specific reactive lymphocytic hyperplasia and immune reactive hyperplasia. Factors such as bacteria, viruses, drugs, metabolites and allergic stimuli cause reactive hyperplasia of lymphocytes and mononuclear macrophages in lymph nodes, which manifests as enlarged lymphatic follicles, proliferation of parafollicular lymphocytes and necrotic hyperplasia, leading to enlarged lymph nodes.
4. Histiocytic hyperplasia: Langerhan’s histiocytic hyperplasia can lead to cell proliferation in the lymph nodes, manifesting as enlarged lymph nodes; Niemann-Pickz cells and Gautier cells accumulating in large numbers in the lymph nodes can lead to enlarged lymph nodes.