Nodules are considered to be caused by the following: 1. due to a low immune system or the presence of an infection. 2. related to having an immune disorder that is related to genetic factors. In addition, it also depends on which kind of nodule it is, because different nodules have different causes of development. For example, the more common breast nodules in women, this disease is usually caused by the patient’s endocrine disorders, environmental factors, frequent temper tantrums, emotional ups and downs, and other conditions. Most of the lung nodules are due to tuberculosis, and after the inflammation is cured, simple tumors or nodular lesions appear. Considering the complexity of the cause, once the nodules are present, they should be treated in a timely manner to avoid missing the best treatment time and making them malignant.