What does the thyroid gland actually do? The thyroid is a very important gland in vertebrates and is an endocrine organ. In humans, the thyroid gland is shaped like a butterfly, like a shield armor, hence the name. The surface of the thyroid gland is covered with connective tissue. The surface connective tissue penetrates deep into the parenchyma of the gland and divides the parenchyma into many inconspicuous lobules, which are lined with thyroid follicles and parafollicular cells. The thyroid gland controls the rate at which energy is used, makes proteins, and regulates the body’s sensitivity to other hormones. The thyroid gland relies on the production of thyroxine, called tetraiodothyronine (T4), to regulate these responses. Both regulate metabolism, growth rates, and mediate other body systems.T3 and T4 are synthesized from iodine and tyrosine. The thyroid gland also produces calcitonin, which regulates calcium balance in the body. What are the common thyroid disorders? Thyroid disorders include nodular goiter, thyroid adenoma, goiter simplex, Hashimoto’s thyroiditis, hyperthyroidism, hypothyroidism, and thyroid cancer. The incidence of thyroid neoplastic diseases are nodular goiter, thyroid cancer, and thyroid adenoma in that order. How to choose the surgical treatment for thyroid diseases? Thyroid nodules: Surgery is the treatment of choice for thyroid nodules of unknown nature prior to surgery. For unilateral thyroid nodule, thyroidectomy of the affected side plus isthmus thyroidectomy + intraoperative rapid frozen section is feasible; if the result of rapid section is malignant, the residual thyroid gland needs to be resected, and there is no evidence of cervical lymph node metastasis preoperatively, and prophylactic lymph node clearance is not advocated; if there is lymphatic metastasis in cervical region, the corresponding regional lymph nodes will be cleared intraoperatively. If the patient has multiple bilateral thyroid nodules, if surgical treatment is needed, subtotal thyroidectomy or total resection is recommended. Do I need to take medication after thyroid tumor surgery? Patients with benign thyroid lesions who undergo subtotal thyroidectomy need to take eugenol replacement therapy if they have hypothyroidism after surgery. Patients with multiple thyroid nodules who have undergone partial or major resection may consider taking Euthyrox for two years after surgery to prevent recurrence, and then stop taking the drug after two years if the thyroid function is normal; if the function is insufficient, the drug should be taken for the rest of the patient’s life. Thyroid cancer patients need to be treated with thyroid hormone suppression therapy after surgery, the purpose of taking eugenol is not only to replace thyroid hormone therapy, but also to regulate thyroid hormone at the low-risk level of thyroid cancer recurrence and metastasis.