Breast nodules are one of the common breast diseases in women and can be classified into four major categories according to etiology: first, cystic hyperplasia of the breast, which occurs in women of childbearing age and is characterized by periodic pain in the breast with nodular changes in the breast, with the pain increasing before menstruation and relieving after menstruation. Secondly, breast fibroids are tough, mobile, regular, smooth lumps that can be palpated in the breast, mostly solitary, but occasionally multiple. Third, intraductal papilloma, the onset of which is insidious, is often detected due to old blood stains in the underwear, and bloody fluid can be seen oozing out when squeezing the nipple. Fourthly, breast cancer, which has no characteristic clinical manifestation in early stage, may appear as a generalized symptom such as body wasting and orange peel sign or dimple sign when it progresses to advanced stage. Therefore, once a nodule is found in the breast, you should go to a regular hospital to have an ultrasound examination of the breast to clarify the benignity and malignancy of the nodule, and if it is a benign nodule, you can review the ultrasound regularly.