During non-pregnancy and non-lactation periods, the flow of fluid when squeezing the nipple is called nipple discharge. Nipple overflow is one of the common symptoms of breast diseases. According to statistics, the number of people who visit the doctor with nipple overflow as the first symptom accounts for 3%-14% of breast diseases, and the incidence is second only to breast lumps and breast pain. If the nipple overflow is a single nipple overflow, most of them are related to the following breast diseases: 1. 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 are bloody. Laboratory examination of the overflow shows a large number of plasma cells and lymphocytes without tumor cells. The disease is more common in non-lactating or menopausal women over 40 years of age. The lump is often less than 3 cm in diameter and the ipsilateral axillary lymph nodes may be enlarged, soft and painful to the touch. If the lump is complicated by infection, the inflammatory manifestation of the lump is red, swollen, hot and painful. 2, intramammary duct papilloma This disease is common in people aged 40-50 years old, 75% of the tumors occur in the area adjacent to the nipple, the tumor is very small, with a tip and villi, and there are many thin-walled blood vessels, so it is easy to bleed. The tumor cells can be found in the overflow of laboratory test. Sometimes patients can find cherry-sized lumps under the areola when they palpate the breast carefully, which are soft, smooth and active. 3. Cystic hyperplasia of the breast is more common in women of childbearing age. Some patients have yellow-green, brown, bloody or colorless plasma-like nipple discharge, and no tumor cells are present in the discharge on laboratory examination. The disease has two characteristics: first, it is characterized by periodic swelling and pain in the breast, which often occurs or is aggravated during the premenstrual period, and is not minded by the patient in mild cases, but can affect work and life in severe cases. The second is that breast lumps are often multiple and can be seen on one or both sides, or can be confined to a part of the breast or scattered throughout the breast. The lumps are nodular in shape and vary in size, tough and not hard, not adherent to the skin, and not well defined from the surrounding tissues. Some breast cancer patients have bright red or dark red nipple overflow, sometimes clear water overflow, colorless and transparent, occasionally viscous, and no trace of cancer cells can be found in the overflow after laboratory examination. The onset of the disease is slow. Patients may unintentionally find breast lumps, mostly in the upper outer quadrant, painless and gradually larger. In advanced stages, orange peel-like skin changes and satellite nodules appear at the site of the lesion. The axillary lymph nodes are enlarged, hard and fuse with each other to form a mass as the disease progresses. The following are some of the things to note: a. Whether the overflow is true or false. True overflow refers to the flow of fluid from the ducts of the breast. Pseudo-exudate is common in sunken nipples, where the epidermal cells of the nipple accumulate in the sunken area, causing a small amount of liquid-like bean curd-like exudate, often with a foul odor. Once the sunken nipple is pulled out and local cleanliness is maintained, the “overflow” will disappear. Second, whether the overflow is bilateral or unilateral. Bilateral overflow is physiological, and most women will still have a small amount of milk secretion if they stop breastfeeding for a year. In the middle and late stages of pregnancy, some pregnant women may have a little light-colored colostrum squeezed out of both breasts. A few women may also experience a short period of milk overflow after a strong orgasm due to high blood vessel congestion in the breasts, breast distention, and erect nipples. When women go through menopause, some of them produce small amounts of milk due to endocrine disorders. All of the above are physiological conditions and are not pathological. However, bilateral nipple overflow can also be pathological, such as a condition called amenorrhea-overflow syndrome, which is caused by pituitary microadenoma and is associated with amenorrhea, headache, narrowing of the visual field, and elevated prolactin in the blood, in addition to overflow. CT brain examination can confirm the diagnosis. Another kind of double nipple overflow is seen in patients with few mastopexy. Thirdly, whether the overflow is single or multiple holes. The nipple has 15-20 openings for the milk ducts. When overflow occurs, it is important to observe from which opening or openings the fluid is spilling. Single-porous overflow is most often an intraductal papilloma. Porous overflow may be physiologic, pharmacologic, systemic benign disease, or mastopexy. Fourth, whether the overflow is spontaneous or spilled after squeezing. The former is mostly pathological, and about 13% of breast cancer patients have a history of spontaneous overflow. Benign or physiological overflow is more common after squeezing. V. The nature of overflow. Different diseases of the breast have different traits when it comes to overflow. For example: (1) milk-like. Mostly physiological, such as after weaning or abortion in the near future, not a manifestation of cancer. (2) Purulent overflow, mostly ductal dilatation, plasmacytoid mastitis. (3) Yellowish overflow is the most common type of overflow and is seen in almost all kinds of breast diseases, with mastopexy being the most common. Some are also intraductal papilloma or breast cancer. Therefore, this is something to be vigilant about. (4) Bloody overflow, which can be of different colors such as bright red, coffee, yellowish, brown, etc. This kind of overflow is a danger sign and should be highly alert, of which 50-75% are intraductal papilloma and 15% breast cancer. If the bloody overflow occurs after menopause, 75% of them are breast cancer. (5) Clear watery overflow, colorless and transparent, occasionally sticky, leaving no trace after overflow. This kind of overflow may be a sign of breast cancer and should be further examined. In conclusion, nipple overflow is an important breast symptom, 10%-15% of which may be breast cancer. Symptoms should be promptly seen in the hospital for cytological examination of the overflow smear. Near-infrared breast scan has a positive diagnosis rate of 80%-95% for ductal lesions in the areola area, and ultrasound and mammogram also have a comparable accuracy rate. Selective lesion ductography is a commonly used test for nipple overflow and has greater value in the differential diagnosis of benign and malignant with nipple overflow, it can also provide physicians with accurate positioning of the extent of surgical excision. Please visit the mammography department of your hospital in time.