Diffuse thyroid lesions are not necessarily cancerous and need to be evaluated in conjunction with other tests and regular follow-ups to determine if they are cancerous. Diffuse thyroid lesion is a kind of thyroid lesion, which is mainly seen in nodular goiter, Hashimoto’s thyroiditis, Graves’ disease and thyroid cancer. 1. Nodular goiter: Cancer is less likely to occur. It should be reviewed regularly and can be treated with levothyroxine sodium or surgery. 2. Hashimoto’s thyroiditis: the possibility of cancer is relatively small, and the condition should be determined by regular ultrasound and thyroid function; when hypothyroidism occurs, it can be treated with levothyroxine sodium, and surgery can be considered for those who have compression symptoms or those who are suspected to have malignant lesions. 3. Graves’ disease: the possibility of cancer is small, and it can be treated with anti-thyroid drugs (such as propylthiouracil, methimazole, etc.) or radioactive iodine and surgery. 4. Thyroid cancer: diffuse thyroid lesion itself can be seen in thyroid cancer. When diffuse thyroid lesions occur, one should go to regular hospitals in time and be treated under the guidance of doctors.