1.Dilatation of mammary ducts: some patients with this disease, the first symptom of early nipple discharge. The color of the overflow is mostly brown, and a few of them are bloody nipple overflow; the laboratory examination of the overflow shows that there are a large number of plasma cells and lymphocytes without tumor cells. The disease occurs in non-lactating or menopausal women over 40 years of age. There is a lump adherent to the skin in the areola area where the overflow occurs, often less than 3 centimeters in diameter, and the lymph nodes in the axilla on the same side may be enlarged, soft, and tender. If complicated with infection, there are red, swollen, hot and painful inflammation in the local area of the lump. 2.Papilloma in the milk ducts: this disease is common in 40~50 years old people, 75% of the tumor occurs in the parts adjacent to the nipple, the tumor is very small, with the tip and villi, and there are a lot of thin-walled blood vessels, so it is easy to bleed. Tumor cells can be found in the overflow. Sometimes the patient can touch the breast carefully and find a cherry-sized lump under the areola, which is soft, smooth and movable. Breast cystic hyperplasia: it is common in women of childbearing age. Some patients have yellowish green, brown, bloody or colorless plasma-like nipple discharge, and no tumor cells exist in the discharge. There are two characteristics of this disease: first, it is manifested as cyclic breast swelling and pain, occurring or aggravated in the pre-menstrual period, which is not minded by the patients in mild cases, but can affect the work and life in severe cases. Secondly, breast lumps are often multiple, can be seen on one side or both sides, can also be limited to a part of the breast or scattered throughout the breast. The lumps are nodular and of different sizes, tough and not hard, with no adhesion to the skin and unclear boundaries with the surrounding tissues, and the lumps can be reduced after menstruation. Breast Cancer: Some breast cancer patients have bright red or dark red nipple discharge, and sometimes produce watery discharge, which is colorless and transparent, occasionally viscous, leaving no trace after discharge, and cancer cells can be found in the overflow in the laboratory. 45~49 years old and 60~64 years old are the two peaks of this disease. The onset of the disease is slow, and patients may find breast lumps unintentionally, which are mostly located in the inner upper limit or outer upper limit, painless and gradually enlarged. In advanced stage, the lesion site appears orange peel-like skin changes and satellite nodules. Axillary lymph nodes are enlarged, hard, and fused with each other to form clusters with the progression of the disease.