A hard lump in the breast can often appear before the menstrual cycle and is affected by estrogen levels, resulting in proliferative changes in the breast, which can be palpated as a hard lump and accompanied by symptoms such as breast swelling and pain, which can appear or disappear with the menstrual cycle. In thin women with less subcutaneous fat, breast tissue that lacks fat and is tougher can be palpated during self-examination, which is a normal physiological manifestation. However, in some cases, it can also be seen in pathological manifestations: 1. Mastoproliferative disorders: Excluding physiological hard lumps caused by hormonal changes at special times, imbalance in the ratio of estrogen and progesterone and abnormal changes in hormone levels may lead to the appearance of mastoproliferative disorders, and nodules in the breast may also show hyperplastic manifestations, and patients may feel granular, striated and other nodules of varying shapes on self-examination, which are generally small and can be single or multiple, and may also They may be accompanied by symptoms such as breast pain and nipple discharge. Patients can undergo ultrasound, breast ductoscopy and other examinations to determine the nature of the nodule, benign lesions can take oral prolotherapy to relieve symptoms, malignant lesions need timely surgery to remove; 2, breast fibroids: local breast tissue hypersensitive to estrogen may proliferate breast fibroids, can be touched single or multiple lumps, slightly hard texture, smooth surface easy to move, no adhesion with the surrounding tissue, can make patients touch the breast there are hard lumps. Breast cancer is a typical symptom of breast cancer, which is a hard lump with irregular shape, hard texture and unclear boundary with surrounding tissues, accompanied by nipple overflow and breast pain. In addition, if a woman is breastfeeding, she may have hard nodes in her breasts due to milk not being drained in time, which may also be accompanied by local pain and discomfort.