1. What is a thyroid nodule? A thyroid nodule is a lump in the thyroid gland and is a common clinical condition. They can be caused by a variety of etiologies, such as: tumors, cysts, inflammatory masses or other diseases. Thyroid nodules can be solitary or multiple. Multiple nodules have a higher incidence than solitary nodules, but solitary nodules have a higher incidence of thyroid cancer. Thyroid nodules are detected by palpation in 1-5% of cases and by ultrasound in up to 19-67% of randomized populations, more commonly in women and older populations. Thyroid nodules are both benign (95%) and malignant (5%), and sometimes it is difficult to identify the nature of the nodule based on clinical presentation and ultrasound alone, and a combination of history, laboratory tests and biopsy is required to make a reasonable diagnosis. Therefore, when thyroid nodules are found, don’t panic and go to the hospital first. 2. Why do thyroid nodules grow? The prevalence of thyroid nodules is gradually increasing, and a significant number of people are found through routine medical examinations. The reasons for the occurrence of nodules are complex and are currently thought to be related to genetics, radioactive exposure, iodine intake, immunity, etc. A history of radioactive exposure in the neck is an important causative factor for thyroid cancer, and patients with autoimmune thyroiditis are prone to develop thyroid nodules. There is very little evidence that thyroid cancer (except familial medullary thyroid carcinoma and papillary thyroid carcinoma) is hereditary. Also, excessive and insufficient iodine intake can cause a variety of thyroid disorders, such as abnormal thyroid function and thyroid nodules. 3.How to deal with thyroid nodules? (1) Thyroid function (mainly changes in TSH): If TSH (thyroid stimulating hormone) is decreased, it suggests that the nodule may be secreting thyroid hormone. (2) Ultrasound of the thyroid gland: Ultrasound of the thyroid gland is necessary to confirm the diagnosis of thyroid nodules. It can clarify the size, morphology, location, richness of blood supply, presence of calcification and burr sign of the thyroid nodules, which is a guide to determine whether the nodules are malignant and whether surgery is needed. If the diameter of thyroid nodules exceeds 25px, with irregular margins, internal blood flow, microcalcifications and other signs of malignancy, it is recommended to do thyroid fine needle aspiration cytology to identify the nature of nodules; for nodules with diameter <25pm, if there are signs of cancer on ultrasound, history of head and neck radiation therapy, and family history of thyroid cancer in first-degree relatives, we should also be highly alert to do further examination. (3) Surgery: For suspected malignant nodules or larger nodules with symptoms of pressure, surgery should be considered. In recent years, the occurrence of malignant thyroid tumors is on the rise. Nodules with a diameter of ≥1 cm and the following conditions require special vigilance: (1) previous radiation treatment to the head and neck; (2) family history of medullary thyroid cancer and multiple intestinal tumors type II; (3) age <20 or >70 years; (4) male; (5) fast-growing nodules; (6) nodules with indistinct margins on imaging; (7) nodules with a high degree of malignancy. (7) fixed nodules; (8) enlarged lymph nodes; (9) hoarseness, cough, dysphagia, dyspnea and other symptoms. 5.What do patients with thyroid nodules need to pay attention to in terms of diet? When thyroid nodules are found, the nature and cause of the nodules should be checked at the hospital promptly, and then a corresponding diet should be adopted according to the different conditions of the nodules. For hyperthyroidism with nodules, a low iodine diet and no seafood such as seaweed and nori are recommended, as this may aggravate the symptoms of hyperthyroidism. In the case of autoimmune diseases such as Hashimoto’s thyroiditis, there is no need to strictly avoid iodine, but you should not consume large amounts of iodine-containing foods as this may aggravate the destruction of thyroid cells. In the case of non-functioning benign nodules, iodine avoidance is not necessary, but regular review is necessary. It is recommended that foods such as radish and cabbage be consumed sparingly, as studies have found that these two foods promote the growth of thyroid nodules.