Mammary gland hyperplasia is one of the most common benign diseases in adult women. Many women worry that it is breast cancer when they have hard lumps in their breasts, and they worry about cancer once they are detected. Therefore, they are very afraid of mastopexy and worry about cancer. In fact, mammary gland hyperplasia is a common disease among women aged 30-50, which is a disorder of the normal structure of the breast, not an inflammatory disease, and not cancer, and most of them will not be transformed into cancer. It is because of the lack of understanding of it that many people are overly nervous. 1. What is mastocytosis? Mammary gland hyperplasia, also known as “mammary adenopathy”, is a benign hyperplasia of breast tissue. Therefore, it is neither a tumor nor an inflammatory disease. Among women over the age of 30, 50% of them have varying degrees of breast enlargement. The cause of mastocytosis is a disorder of ovarian endocrine function, i.e. a decrease in luteinizing hormone and an increase in estrogen. Under normal circumstances, women also experience periodic enlargement of breast tissue, but with the cyclical adjustment of hormones, the breast tissue reverts back. However, some women have endocrine disorders and have incomplete breast regeneration, so their breasts feel lumpy to the touch and are accompanied by swelling and pain before menstruation, which is relieved after menstruation. We emphasize that mammary gland hyperplasia occurs mostly in the age of 30-50 years old to distinguish it from physiological hyperplasia in adolescents and during pregnancy and lactation. In adolescent girls, it is normal for the mammary glands to start developing, even if they feel slightly swollen and painful; during breastfeeding and pregnancy, it is also normal for the mammary glands to prepare for feeding the baby. After menopause, because the overall level of endocrine decline, especially estrogen began to reduce, mammary gland hyperplasia is rare, then there are breast lumps, it is necessary to exclude the possibility of tumors. 2.Can mammary gland hyperplasia become cancerous? Histologically, there are many kinds of mammary gland hyperplasia, and the possibility of cancer varies. The most common type of hyperplasia is simple lobular hyperplasia, which accounts for 70% of all mammary gland hyperplasia, and this type of hyperplasia will not become cancerous; ductal epithelial hyperplasia without cellular anomalies accounts for 20%, and only 1%-2% of them may become cancerous; ductal epithelial hyperplasia with cellular anomalies accounts for 10% of patients, and 2%-4% of them with mild cellular anomalies will become cancerous. -Among them, 2% of mild cellular anomalies will become cancerous and 75%-100% of severe anomalies will become cancerous, which should be reviewed in hospital every 3 months. As seen above, more than 90% of mammary gland hyperplasia is safe and will not become cancerous, so patients only need to check themselves regularly and go to the hospital for review. 3.How to distinguish hyperplasia from tumor? According to statistics, the incidence rate of breast cancer in China is more than 50 per 100,000, and there is a rising trend in recent years. Women with breast hyperplasia, especially those with family history of cancer, early menarche, late menopause, late childbearing, infertility and non-lactation, should still pay attention to differentiate hyperplasia and tumor. It is not difficult to distinguish between the two. Mammary gland hyperplasia usually develops bilaterally at the same time and is felt as a swelling and pain associated with the menstrual cycle. The borders of the lumps are not clear to the touch, or they are bead-like, and their texture is not very hard and they do not adhere to the skin. This is not the case with breast cancer, where patients are often initially asymptomatic. The first common symptom is the discovery of a lump that is clearly distinguishable from the surrounding breast tissue, and more than 80% of them are felt by the patients themselves. The location of the lump is variable, but the upper outer area of the breast is the most common. If a hard, thickened area or lump distinctly different from the surrounding tissue is felt in one breast but not in the other, be alert to the possibility of cancer. Breast cancer often starts as a painless lump, even though some patients have pain, mostly with breast enlargement. The tumor usually occurs in one breast, but there are also bilateral cases. The lump has a distinct border with adhesions to the skin, sometimes with sunken nipples, showing orange peel-like skin changes or even ulcers. When the lump is pushed with fingers, it can move freely under the skin at the beginning, but when it develops further, the lump can adhere to the chest wall and cannot be moved. At this point, the patient must go to the hospital for examination in order to make accurate diagnosis and timely treatment. The current auxiliary diagnostic methods include ultrasound and mammography, while infrared examination is not very accurate and therefore not recommended. If it is still difficult to confirm the diagnosis, biopsy can be performed.