Fluid coming out of the nipple during non-pregnancy and non-breastfeeding periods is called nipple discharge. Nipple discharge is a common symptom of breast diseases, accounting for about 5-10% of breast diseases. There are physiologic and pathologic nipple discharge, of which about 10%-15% of pathologic nipple discharge has malignant lesions, so we should be vigilant. Here is a brief introduction to the knowledge of diseases related to nipple discharge. 1.What is nipple discharge? Nipple Discharge (Nipple Discharge) is a common symptom of breast diseases, which is divided into physiological and pathological fluid. Physiological overflow refers to the phenomenon of lactation during pregnancy and breastfeeding. Sometimes bilateral nipple discharge caused by oral contraceptive pills or sedative drugs (such as Valium) and small amount of unilateral or bilateral nipple discharge in postmenopausal women are also physiological discharge, which can be eliminated after stopping the drugs. Pathological overflow refers to non-physiological conditions, not related to pregnancy, breastfeeding, one or both sides of the natural overflow from one or more mammary ducts, the time can be from intermittent, persistent from a few months to a few years. Among them, nipple overflow mainly refers to pathological overflow. 2.What are the causes of nipple discharge? There are two kinds of nipple overflow: true overflow and pseudo-overflow. Genuine overflow refers to the natural overflow phenomenon of non-pregnant and non-lactating nipple, and pseudo-overflow refers to the overflow caused by superficial erosion of nipple or exudation of breast fistula. Among them, the etiology of true nipple overflow can be caused by hemophilia, purpura disease, endocrine disorders, lesions of the ducts themselves and intramammary lesions. The common ones are intraductal papilloma, cystic hyperplasia, ductal dilatation, ductal inflammation, ductal carcinoma, etc., which account for more than 80% of all nipple discharge. Nipple discharge is often unilateral, or can occur on both sides at the same time. The overflowed milk duct can be single duct or multiple ducts. Unilateral single-tube nipple discharge is common in intraductal papilloma, unilateral multiple-tube discharge is common in ductal dilatation, cystic hyperplasia; bilateral multiple-tube discharge is common in endocrine disorders, drug reactions, amenorrhea-milk overflow syndrome, or some benign breast diseases. 3.What is the nature of nipple overflow? (1) Milk-like overflow: the color of overflow is like milk after fat removal. It is commonly seen in amenorrhea-milk overflow syndrome (mastitis), anterior pituitary hyperfunction syndrome, or after taking oral contraceptives. Mostly due to the pituitary function is inhibited, resulting in excessive release of prolactin caused by some patients with breast hyperplasia can also appear similar symptoms, this time often for the two sides of the multiple tubes overflow, automatic outflow. (2) Watery overflow: the overflow is thin and watery, mostly caused by intraductal papilloma, cystic hyperplasia of the breast and breast cancer. Recently, some people think that about 50% of the watery overflow may be cancer. (3) Purulent overflow: the overflow is like pus, which is common in postpartum acute mastitis and breast abscess. (4) Plasmacytoma: the color of the overflow is light yellow, most of the patients are caused by intraductal papilloma in the lower part of the nipple, and it can also be seen in cystic hyperplasia, ductal dilatation of the breast and breast cancer. (5) Pale green overflow: the secretion is light-colored green liquid, which is less common. It is common in cystic hyperplasia of the breast. (6) Bloody fluid or plasma bloody fluid: bloody fluid is red, plasma bloody is pink. Hemorrhagic fluid is more common in intraductal papilloma. unilateral nipple hemorrhagic fluid in patients over 50 years old often suggests that it may be intraductal papillary carcinoma and should be highly valued. Plasma blood can be caused by intraductal papilloma, cystic hyperplasia of breast and intraductal papillary carcinoma. 4.Several common nipple discharge diseases (1) Dilatation of mammary ducts: it is the most common disease causing nipple discharge, and the first symptom of some patients in early stage is nipple discharge, and the color of its discharge is mostly brown, and a few of them are bloody. Generally, this disease does not need surgical treatment, but if it is combined with inflammation of milk ducts, it can be considered to be treated by ductal lavage. Those who do not heal for a long time and have bloody overflow are considered to have the possibility of cancer, and it is necessary to carry out surgical biopsy in time to make a clear diagnosis. (2) Cystic hyperplasia of the breast: it occurs in women aged 30-50. A few patients have self-conscious hidden pain or discomfort, and some patients can find single or multiple lumps in both breasts, and the size of the lumps and the pain can be relieved after menstruation. Some patients have nipple discharge phenomenon, which can be plasma, plasma blood or blood. And according to the literature, the cancer rate of this disease is 1%. The principle of treatment is that for patients with obvious lumps, regular follow-up is required; for patients with hard lumps, older age, nipple bleeding and inability to remove the cancer, pathologic examination after lump or regional excision is feasible. (3) Intraductal papilloma of breast: This disease is most common in women aged 30-40. The main clinical manifestation is the intermittent natural discharge of old blood and water from the nipple, and a few of them are brownish yellow or yellow plasma. About 1/3 of the patients in the areola area can be found in the 0.5-1.0cm size of the soft nodules, after the blood extrusion nodules can disappear. Most of the patients are treated with papilloma and involved ductal resection. (4) Intraductal papillary carcinoma of breast: It is mostly seen in old and prolific women, and is a special type of breast cancer with slow onset and long history, usually more than 5 years; the first symptom is an intramammary lump, which is often large, hard and often adheres to the skin; about 1/4 of the patients have bloody nipple overflow, which is often a single-tube overflow. (5) Breast cancer with nipple blood overflow: bloody overflow is common, and most of them are unilateral single duct overflow (bilateral multiple duct overflow, the possibility of benign lesion is high). It is often accompanied by obvious lumps, and the lumps are mostly located outside the areola area, mostly >2cm. more attention should be paid to those who are over 45 years old. 5, the general diagnosis and treatment process of nipple overflow: (1) for patients with nipple overflow, first of all, we should know in detail about her (his) onset of the disease and the nature of the overflow, and then carry out a detailed physical examination to clarify whether the nipple overflow is real or not, and to determine the nature of the nipple overflow, the amount of nipple overflow and the approximate location of the overflowing milk ducts, and whether there is any combination of breast lumps and so on. (2) Mammography and endoscopy are routinely performed in patients with any nipple discharge. Combined with the results of endoscopy and specific nipple overflow symptoms, the general diagnosis and treatment are as follows: ① for patients with milky, plasma and watery overflow, breast ultrasound and endoscopy did not find obvious space-occupying lesions, may not require surgical treatment, close observation can be; ② for patients with bloody overflow, breast ultrasound and endoscopy did not find obvious space-occupying lesions, no special treatment, regular review can be, if the long-lasting or obvious increase in trend, after further examination of the patient, the patient can be treated with special treatment. If it is not cured for a long time or the trend is obviously increased, after further examination, surgical treatment can be considered; ③ For breast tube endoscopy found that there is a space-occupying lesion, regardless of the nature of any overflow, it is recommended that surgical treatment; ④ For nipple overflow with a lump, especially the areola mass extrusion of overflow visible, regardless of whether there is a positive finding of the mastoscopy, it is recommended that surgical treatment. (3) For medical institutions that do not have the conditions to carry out mammography, smear cytology of overflow, mammography, mammography or breast MRI are feasible. Especially for those with bloody overflow and age >45 years old, even if there is no mass palpable, and there is no positive finding on cytology of overflow, mammography or MRI, surgical excision is recommended to make a definitive diagnosis.