A nodule under the chin may be normal thyroid tissue. The normal anatomical location of the thyroid gland is located in the front of the neck, on both sides of the trachea below the laryngeal nodes, but it cannot be touched under normal circumstances. If a nodule appears in the thyroid gland, an enlarged thyroid gland can be palpated in the larynx. In addition to thyroid nodules, nodules under the chin can also be seen as a result of thyroiditis, enlarged lymph nodes, cysts or tumors, which require targeted treatment after clarifying the cause: 1. Thyroid nodules: Due to excessive hyperplasia of normal thyroid tissue, or abnormal thyroid hormone levels in the body due to low iodine intake, can cause thyroid nodules, which can be touched under the chin. When the nodules compress the surrounding tissues, hoarseness and a foreign body sensation in the throat may occur. It is usually necessary to apply antithyroid drugs to control thyroid stimulating hormone levels, such as thiourea compounds, and if necessary, surgery. 2. Thyroiditis: It may be caused by bacterial, fungal, viral infections or drugs, trauma, and other factors, resulting in inflammatory changes such as destruction of the thyroid follicular structure or necrosis, leading to thyroiditis, which is manifested by an enlargement under the chin that is hard to the touch. Similar to nodules, it may be accompanied by systemic symptoms such as insomnia, palpitations, and fear of heat. Usually medication, such as propranolol, aspirin, etc., is used to relieve symptoms; 3. Lymph node enlargement: a node under the chin may be a local lymph node enlargement, mostly caused by inflammation, such as upper respiratory tract infections, oral infections and other bacterial infections, herpes stomatitis, and viral infections such as HIV infection, or parasitic infections such as filariasis, toxoplasmosis, etc., can cause local neck Lymph node enlargement can also be caused by immune factors, such as systemic lupus erythematosus, hyperthyroidism and other immune diseases, which can be accompanied by night sweats and fever with chills. General inflammation can be treated with anti-infection drugs, while immune diseases require long-term application of immunosuppressive drugs to control the development of the disease; 4, cysts: submandibular gland cysts and sebaceous gland cysts can also lead to nodules under the chin, and patients with submandibular gland cysts often show symptoms such as swelling, fever and pressure pain in the submandibular area, while sebaceous gland cysts can show local subcutaneous spherical cystic swellings with clear borders, spherical shape, adhesion with the surrounding skin, and smooth surface. Patients can be diagnosed by ultrasound, CT and histopathological examination, all of which can be treated by surgical excision to improve the symptoms; 5. Tumors: such as lymphocytic leukemia, breast cancer, lung cancer and other tumor metastases can lead to lymph node enlargement, thus manifesting as nodules under the chin, while nodules caused by thyroid cancer are irregular in shape, have local pain symptoms and can be accompanied by The nodules caused by thyroid cancer are regular in shape and have local painful symptoms, which can be accompanied by difficulty in swallowing and breathing, as well as coldness, weakness and flushing, etc. Surgery is usually the common treatment, and chemotherapy and radiotherapy can also be applied to control the development of the disease.