Thyroid nodules can be classified as benign or malignant by nature, with the majority being benign and less than 1% being malignant. Depending on the pathology, they can be classified as: nodular goiter, thyroid adenoma, thyroiditis, thyroid cancer, etc. Early recognition of the nature of thyroid nodules and differentiation of benign or malignant lesions is important for the selection of treatment options and prognosis. The clinical manifestations and treatment principles of different types of thyroid nodules vary. The following is a description of common thyroid nodules: Nodular goiter Nodular goiter is a benign disease, most often seen in middle-aged women. The disease progresses slowly and most patients are asymptomatic. Larger nodular goiters can cause symptoms of compression. Acute bleeding within the nodule can lead to sudden enlargement and painful masses, breathing difficulties, swallowing difficulties and hoarseness. Ultrasound of the thyroid gland can clarify the location, size, boundaries, number, and cystic or solid nature of the nodules. For nodular goiter, thyroid hormone treatment can be tried if the nodule is small, and treatment can be continued if the nodule shrinks after treatment, but surgery should be performed as soon as possible if the nodule increases in size, involves surrounding tissues, or has the potential to become malignant. Thyroid adenoma Thyroid adenoma is the most common benign tumor of the thyroid gland. Adenomas grow slowly and are mostly solitary. The lump is round or oval, tough, well-defined, smooth, painless, and moves up and down with swallowing. Most patients are asymptomatic. Thyroid adenomas can be cured after excision and have a good prognosis, and those that recur after surgery can be treated with surgery again. Since the cause of the disease is still unknown, early detection and treatment are the best measures to prevent the development of the disease. Chronic lymphocytic thyroiditis Chronic lymphocytic thyroiditis, also known as Hashimoto’s thyroiditis, is a chronic inflammatory autoimmune disease that uses its own thyroid tissue as the antigen, and is the most common form of clinical thyroiditis. It is a chronic inflammatory autoimmune disease with antigen in the thyroid tissue. The main manifestations are diffuse or limited enlargement of the thyroid gland, with a firm and elastic texture, clear borders, no tenderness, and no enlargement of the cervical lymph nodes. Needle aspiration cytology of the thyroid gland may clarify the diagnosis. Patients with obvious enlargement of the thyroid gland, significant pressure symptoms and rapid progression of the disease may be considered for treatment with adrenocorticotropic hormone with a view to obtaining better efficacy in the short term and maintenance treatment with thyroid hormone after stabilization. For patients with suspected malignant changes, surgery should be performed promptly. Thyroid cancer There are four types of thyroid cancer: papillary, follicular, medullary and undifferentiated carcinoma. Their age of onset, growth rate, metastatic pathway and prognosis are all different. For example, the 10-year survival rate of papillary carcinoma is nearly 90% after surgery, while undifferentiated carcinoma has a very short course and usually survives only a few months. Genetic factors, excessive iodine intake or iodine deficiency, and ionizing radiation can change the structure and function of the thyroid gland, and some thyroid adenomas, chronic thyroiditis, and nodular goiter can become cancerous. Cervical lymph node metastasis is the most common form of thyroid cancer, followed by metastasis to lung, bone and liver through blood. Thyroid cancer lumps are hard, ill-defined and poorly mobile, and may be accompanied by enlarged lymph nodes in the neck. Ultrasound shows an ill-defined mass with uneven echogenicity, rich blood flow and dotted calcifications. Needle aspiration cytology of the mass may provide more valuable information. Once thyroid cancer is diagnosed or suspected, surgery should be performed as early as possible with comprehensive postoperative treatment and regular review. Once a thyroid nodule is found, it should be properly treated by a specialist. Those diagnosed or highly suspected of malignancy should be operated as early as possible. Although multiple nodules or single adenomas are benign lesions, some patients may develop secondary hyperthyroidism or carcinoma, and early surgery is also recommended. The nature of thyroid nodules and the function of thyroid gland are different, and the dietary requirements are very different. For thyroid cancer and hyperthyroidism, iodized salt and foods with high iodine content are forbidden, and a reasonable diet should be taken under the guidance of a specialist.