“Ask Dr. HKSH” - Should I worry about nipple discharge?

Dr. CHEUNG Ho Hung, Billy

Specialist in General Surgery

Q1.  When do patients usually discover nipple discharge?

Patients usually notice nipple discharge in two situations: either when they see coloured stains on their bra or underwear, or while changing clothes or bathing. Patients should be particularly cautious if they occur outside the lactation period.

Q2.  Why does nipple discharge suddenly occur?

Let us begin with the breast structure. The mammary glands are composed of glandular lobules, where milk is produced. These lobules are connected to a network of ducts that lead to the nipple. Milk flows along these ducts and out of the nipple. When nipple discharge is noted, the problem may arise from either the ducts or lobules.

Q3. How can you tell different types of nipple discharge apart?

Nipple discharge varies with the underlying causes. If it has a benign (non-cancerous) cause, such as the menstrual cycle or hormonal changes, the discharge is usually clear, yellowish or milky-white. It often comes from both nipples at the same time, as the breast tissues on both sides are affected by hormonal or menstrual changes at the same time.

However, if the discharge comes from one breast only, or from a single opening on the nipple, or is red and bloody, extra care is needed, as this may indicate a problem within a single milk duct or lobule.

Q4. Does abnormal discharge necessarily mean breast cancer?

Abnormal discharge does not necessarily mean breast cancer. However, as mentioned earlier, it is important to find out if the discharge is related to hormonal or menstrual cycle changes, or a local problem. If it is a localised problem, most cases are still benign, such as widening of the milk ducts (duct ectasia), or benign growths inside the milk ducts, such as papillomas (small wart-like growths). Nevertheless, breast cancer can also cause nipple discharge, so the possibility of cancer cannot be ruled out.

Q5. How is abnormal nipple discharge diagnosed?

Just like a general breast assessment, abnormal nipple discharge is often diagnosed in three steps: it begins with medical history taking and clinical examination, followed by imaging investigations, mostly ultrasound, and also mammogram (breast X-ray) when necessary, for any signs of abnormal dilatation of milk ducts, abnormal tissue within the ducts, or abnormal growth in the breast that requires treatment. And the third step is to extract breast tissue for pathological examination if any abnormality is identified.

In certain circumstances, the doctor may collect a sample of the discharge to check for abnormal cells. If the cause remains unclear, additional investigations may be arranged. These include magnetic resonance imaging (MRI) to look at the milk ducts and breast tissue in detail, with a contrast injection to make the images clearer. Ductography (an X-ray of the milk ducts using dye) may also be performed to detect abnormal changes within the ducts. All these investigations are prescribed by doctor based on individual cases.

If a hormonal cause is suspected, blood tests and even examinations of other body parts are conducted to identify any underlying endocrine disorder. Referral to the appropriate specialist for further evaluation and treatment may also be required.

Q6. How is nipple discharge managed?

If the discharge is confirmed to come from one breast, doctor will identify the underlying cause based on the above investigation results and decide on a treatment plan. This generally involves two steps. If an abnormal area in the breast needs to be removed, depending on its size, the doctor may first mark its position before removing it.

Any abnormality in the milk duct is marked by contrast imaging or injection. During surgery, a small cut is made at the edge of the areola to find and remove the affected duct, which is then sent to the laboratory for testing.. After removal of the abnormal duct and associated breast tissue, the duct is ligated to reduce the risk of infection or recurrence of discharge. If the discharge turns out to be caused by cancer, it will be treated according to the breast cancer treatment plan.

Q7. Are there any risks associated with duct excision surgery?

Duct excision surgery (also called microdochectomy) is usually performed through a small cut at the edge of the areola, and the abnormal duct is removed and tied off. Although the risks of the procedure are generally low, it may cause impact in certain aspects. First, as some ducts are removed and tied off, it may affect breastfeeding in future. Second, as the incision is made at the areolar margin, there may be changes in nipple or areola sensation, or occasionally in blood supply to the area. Third, the scar at the areola may become thickened or uncomfortable.

In addition, as with any surgical procedure, it carries a risk of inflammation, infection, bleeding and fluid build-up (seroma). Should abnormal cells or cancer is confirmed in the pathology report after duct excision, one may need further surgery for extensive tissue excision to ensure oncological safety.