Patient's question:
Currently, in general: I have had nipple discharge on both sides for over 10 years. During this period, I have undergone a brain CT scan, the results of which showed no abnormalities. I have also had a nipple secretion test, which also revealed no issues. I don't know the cause, but as soon as I gently squeeze my nipples, clear, colorless liquid flows out. I hope the doctor can help me with an explanation. Thank you.Doctor's answer:
In non-pregnant and non-lactating periods, fluid discharge from the nipple is referred to as nipple discharge. Nipple discharge is one of the common symptoms of breast diseases. Statistics show that 3% to 14% of patients seeking medical attention primarily due to nipple discharge have breast diseases, with its incidence rate ranking second only to breast lumps and breast pain. If the nipple discharge is unilateral, it is often associated with the following breast diseases:1. Mammary Duct Ectasia: In some patients with this condition, the initial symptom is nipple discharge. The discharge is typically brown, occasionally bloody. Laboratory tests reveal a high concentration of plasma cells and lymphocytes, with no tumor cells present. This condition is more common in non-lactating women over 40 or postmenopausal women. The area around the nipple where discharge occurs may have a mass adhering to the skin, usually less than 3 cm in diameter. The ipsilateral axillary lymph nodes may be swollen, soft, and tender. If infection occurs, the mass may present with redness, swelling, heat, and pain.
2. Intraductal Papilloma: This condition is more common in women aged 40 to 50. 75% of the tumors are located near the nipple. The tumor is small, pedunculated, and covered with villi, with thin-walled blood vessels, making it prone to bleeding. Tumor cells can be found in the discharge upon laboratory examination. Sometimes, patients may notice a cherry-sized mass under the areola during careful breast examination, which is soft, smooth, and mobile.
3. Breast Cystic Hyperplasia: This condition is more common in women of reproductive age. In some patients, the nipple discharge may be yellow-green, brown, bloody, or serous. Laboratory tests show no tumor cells in the discharge. This condition has two characteristics:
- It presents with cyclical breast pain, often worsening before menstruation. Mild cases may go unnoticed, while severe cases can affect daily activities.
- Breast lumps are often multiple, appearing in one or both breasts, or localized to a part of the breast. The lumps are nodular, of varying sizes, firm but not hard, not attached to the skin, and poorly defined. They may shrink after menstruation.
4. Breast Cancer: Some breast cancer patients may have bright red or dark red nipple discharge. Clear, watery discharge may also occur, which is colorless, transparent, occasionally sticky, and leaves no trace after leakage. Cancer cells can be found in the discharge upon laboratory examination. The peak ages for this condition are 45–49 and 60–64. The onset is gradual, and patients may notice a breast lump unintentionally, often located in the inner or outer upper quadrant, painless, and gradually enlarging. In advanced stages, peau d'orange skin changes and satellite nodules may appear. Axillary lymph nodes may be swollen, hard, and fused together as the disease progresses.
Additionally, the following points should be noted:
1. True vs. False Discharge: True discharge refers to fluid leaking from the breast ducts. False discharge is common in inverted nipples, where shed epithelial cells accumulate in the, causing a small, cheesy-like leakage with an odor. Once the inverted nipple is pulled out and the area is kept clean, the "discharge" will disappear.
2. Unilateral vs. Bilateral Discharge: Bilateral discharge is often physiological. For example, within one year of stopping breastfeeding, many women still experience small amounts of milk secretion. In late pregnancy, some women may produce a small amount of colostrum from both breasts. In some women, intense sexual climax may cause breast congestion, swelling, and nipple erection, leading to temporary leakage. During menopause, hormonal imbalance may cause some women to secrete small amounts of milk. These are all normal physiological conditions, not pathological. However, bilateral nipple discharge can also be pathological, such as in patients with amenorrhea-galactorrhea syndrome, caused by a pituitary microadenoma. This condition is accompanied by amenorrhea, headache, visual field constriction, and elevated prolactin levels in the blood. A brain CT scan can confirm the diagnosis. Another cause of bilateral discharge is mild breast hyperplasia.
3. Single vs. Multiple Orifices: The nipple has 15–20 openings for milk ducts. When discharge occurs, observe from which one or more openings the fluid is leaking. Unilateral discharge is often associated with intraductal papilloma. Multiple orifices may indicate physiological, medication-related, systemic benign diseases, or breast hyperplasia.
4. Spontaneous vs. Induced Discharge: Spontaneous discharge is more likely to be pathological. Approximately 13% of breast cancer patients have a history of spontaneous discharge. Benign or physiological discharge is more commonly induced.
5. Discharge Characteristics: The nature of the discharge varies depending on the underlying breast condition. For example:
- Milk-like discharge: Often physiological, such as in the immediate aftermath of weaning or miscarriage, and not indicative of cancer.
- Purulent discharge: Often associated with duct ectasia or plasma cell mastitis.
- Light yellow discharge: The most common type, seen in nearly all breast diseases, with breast hyperplasia being the most frequent cause. Some cases may be due to intraductal papilloma or breast cancer, so this warrants increased vigilance.
- Bloody discharge: Can be bright red, coffee-colored, light yellow, or brown. This is a dangerous sign and should be taken seriously. 50%–75% of cases are due to intraductal papilloma, and 15% are due to breast cancer. If bloody discharge occurs postmenopause, 75% of cases are breast cancer.
- Watery discharge: Colorless, transparent, occasionally sticky, and leaves no trace after leakage. This type of discharge may signal breast cancer and requires further examination.
In summary, nipple discharge is an important breast symptom, with 10%–15% of cases potentially being breast cancer. If symptoms appear, seek medical attention promptly for discharge smear cytology examination. Near-infrared breast scanning has a positive diagnostic rate of 80%–95% for ductal lesions in the areola. Ultrasound and mammography also provide reliable accuracy. Selective ductography is a common diagnostic method for nipple discharge, offering significant value in differentiating benign from malignant conditions. It can also help surgeons determine precise resection margins.