There are four common types of thyroid cancer: (1) papillary carcinoma: it is the most common type of thyroid cancer, accounting for about 60% to 70% of thyroid cancer, and is more common in adolescent women. Cervical lymph node metastasis is characterized by high incidence, early appearance, wide range, slow development and cystic transformation. (2) Follicular carcinoma: It accounts for about 15%-20% of thyroid carcinoma, with a higher average age than papillary carcinoma, and is mostly seen in middle-aged women. It is more malignant and prone to distant metastasis, mainly hematogenous metastasis, often to lung and bone. The masses are generally crossed large, mostly unilateral. (3) Medullary carcinoma: originates from parafollicular cells (also called C cells), and can be divided into sporadic and familial, with familial being an autosomal inherited endocrine syndrome. Familial medullary carcinoma mostly involves both thyroid glands, while sporadic medullary carcinoma often involves only one thyroid gland. Medullary carcinoma is highly malignant and often has cervical lymph node metastasis, 53% of which can occur ipsilateral cervical lymph node metastasis and up to 20% bilateral lymph node metastasis. Medullary thyroid carcinoma can secrete many kinds of amines and peptide hormones, causing some patients to have intractable diarrhea, mostly watery diarrhea, but intestinal absorption is not serious, and patients may also have symptoms such as facial flushing and excessive sweating. (4) Undifferentiated carcinoma: It is a type of highly malignant tumor, accounting for about 8% of thyroid cancer. Undifferentiated carcinoma is composed of a series of poorly differentiated cancer cells, including spindle cell, giant cell carcinoma, small cell carcinoma, squamous cell carcinoma, adenoid cystic carcinoma, mucinous adenocarcinoma, etc., among which spindle cell and giant cell carcinoma are the most common. The onset of the disease is mostly in the elderly, with the average age above 60 years. Undifferentiated carcinoma may arise from benign tumors and well differentiated papillary or follicular adenocarcinoma. Patients often have a history of thyroid swelling for many years and are characterized by a sudden increase in size and rapid progression of the disease. Most patients are diagnosed late and lose the opportunity for radical treatment, and treatment is only palliative. The late stage responds poorly to any treatment.