Nipple overflow can be caused by systemic diseases (pituitary tumors, thyroid diseases, etc.), but also by breast diseases. If you find breast overflow, please consult your local regular hospital promptly. The following are breast diseases that cause nipple overflow: 1. Cystic hyperplasia of the breast: it is common in women of childbearing age. Some patients have yellow, brown, bloody or colorless plasma-like nipple overflow, and no tumor cells exist within the overflow on laboratory examination. The disease has two characteristics: First, it is characterized by periodic breast swelling and pain, which often occurs or worsens in the premenstrual period. The second is that breast lumps are often multiple, either on one or both sides, and can be confined to a part of the breast or scattered throughout the breast. The lumps are nodular in shape and vary in size, and they may shrink after menstruation. 2, ductal dilatation of the breast: some patients with this disease, the first symptom of early nipple overflow. The color of the overflow is mostly brown, and a few of them are bloody; laboratory examination of the overflow shows a large number of plasma cells and lymphocytes without cancer cells. The disease is more common in non-lactating or menopausal women over 40 years of age. If it is complicated by infection, the lump has local inflammatory manifestations of redness, swelling, heat and pain. 3. Intraductal papilloma: This disease is more common in people aged 40 to 50 years old. There is bloody papillary overflow during non-menstrual periods, which can be bright red, dark red or brownish yellow. Laboratory tests can find tumor cells in the overflow. Sometimes when the patient palpates the breast carefully, a cherry-sized mass under the areola can be found, which is soft, smooth and mobile. If nipple ductography is performed, it can show a sandy or round filling defect, and the defect is caused by tumor. 4.Breast cancer: Some patients with breast cancer have bright red or dark red nipple overflow, and cancer cells can be found in the overflow. 45-49 years old and 60-64 years old are the two peak incidences of this disease. The onset of the disease is slow. Patients may unintentionally find breast lumps, mostly located in the upper or upper limit of the inner or outer breast, painless and gradually larger. In advanced stages, orange peel-like skin changes and satellite nodules appear at the lesion site. The axillary lymph nodes are enlarged, hard and fuse with each other to form a mass as the disease progresses. The main diseases that can lead to nipple overflow are the ones described above. In addition, it is a normal physiological phenomenon for women to have milk secretion during breastfeeding, so women do not need to be overly nervous and worried, but if some of the above-mentioned diseases cause nipple overflow, we should pay attention to it and actively treat it, and the earlier it is treated, the better. It is recommended that patients undergo a mammogram, which is a 0.75mm (0.6mm or 0.95mm) diameter endoscope that is inserted through the mouth of the milk ducts, and a medical monitor that looks into the end of the milk ducts while observing the situation inside the milk ducts, as far as the fourth or fifth level milk duct branches. The whole examination process takes about 10-15 minutes and requires local anesthetic injection into the overflowing milk ducts. The endoscopic examination of breast ducts can clearly observe the condition of the duct wall and ductal secretions, and describe the color, size, shape, smoothness, etc. if there is an occupying lesion. Breast ductal carcinoma, intraductal papilloma, and ductal inflammation each have their own characteristic endoscopic manifestations of the breast ducts, and thus can be diagnosed accordingly. The other functions of endoscopy are biopsy of the lesion under endoscopic guidance for pathological diagnosis, marking of the lesion on the surface of the body or positioning a guide wire under the ductoscope for accurate positioning for surgery, and treatment of benign diseases in the duct through the ductoscope.