Diffuse thyroid lesions are only imaging manifestations and can be seen in a variety of diseases, and their clinical symptoms vary from disease to disease. For example, hyperthyroidism is characterized by a fear of heat, excessive drinking, and weight loss; hypothyroidism is characterized by a fear of cold and fatigue; and subacute thyroiditis may present with symptoms such as neck pain. 1. Hyperthyroidism: it is usually characterized by fear of heat, excessive sweating, hunger, weight loss, fatigue, shortness of breath, arrhythmia, increased appetite, increased stool frequency, irritability, insomnia, goiter, protruding eyes, and so on. 2. Hypothyroidism: coldness and fatigue, slow reaction, drowsiness and depression, muscle weakness, mucous edema and even coma. 3. Subacute thyroiditis: neck pain, often accompanied by sore throat or fever. It may also be accompanied by symptoms of hyperthyroidism or hypothyroidism. Diffuse thyroid lesions can have many manifestations, and the severity of the disease cannot be determined by the symptoms; further tests are needed to clarify what kind of disease it is. Further tests are needed to determine the type of disease, such as a thyroid panel and thyroid-related antibodies. If diffuse thyroid lesions are detected, it is important to go to the hospital in time to get a clear diagnosis and treatment under the doctor’s supervision.