Breast Nipple Discharge

Etiology

The majority of all nipple discharges are benign in etiology (97%).[1][2][4][3]

Causes of Physiologic Nipple Discharge

1. Pregnancy
2. Lactation
3. Postpartum galactorrhea may last up to two years after delivery
4. After spontaneous or intentional termination of pregnancy
5. Fibrocystic changes of the breast
6. Hormonal fluctuations associated with the menstrual cycle
7. Duct ectasia
8. Intraductal papilloma

Causes of Pathologic Nipple Discharge

1. Infection (periductal mastitis)
2. Breast abscess
3. Neoplastic process of the breasts (e.g., intraductal carcinoma, Paget disease of breast)
4. Pituitary tumor/prolactinoma
5. Thoracic/breast trauma
6. Systemic disease/endocrinopathies that elevate prolactin level (e.g., hypothyroidism, disorders of the pituitary gland or hypothalamus, chronic kidney or liver disorders)
7. A side effect of medications that inhibit dopamine secretion (e.g., opioids, oral contraceptives, antihypertensives (methyldopa, reserpine, verapamil), antidepressants, and antipsychotics)

Epidemiology

Nipple discharge is the third most common breast complaint after breast pain and breast mass. Fifty percent to 80% of women in their reproductive years have nipple discharge, and 6.8% of these are referred to a breast surgeon. Most nipple discharge is benign in origin (97%).[5]

History and Physical

The clinical history is most helpful in distinguishing benign from suspicious or pathologic nipple discharge. The patient's age is very important, as women greater than 40 years of age are at higher risk of having pathologic discharge. Postmenopausal women with nipple discharge are rarely benign.

History of present illness should include the onset of discharge, association with the menstrual cycle, persistence, and the character and color of the discharge. A patient's reproductive history is important (e.g., the age at menarche, age at menopause, and history of pregnancies including age at first full-term pregnancy). Other relevant histories, including a history of any breast problems, including breast biopsies, and surgical history (e.g., hysterectomy and whether ovaries were removed) are required for diagnosis. In premenopausal women, obtain the pregnancies/births history, history of breastfeeding, and the use of oral contraception or hormone replacement therapy (HRT). Family history should contain information about cancers, especially breast/ovaries, and the menopausal status of close relatives. Medications history is of paramount importance, as many medications can cause nipple discharge as a side effect. One must not miss the presence of fever (mastitis or breast abscess), symptoms of hypothyroidism (weight gain, cold intolerance, constipation, amenorrhea), symptoms of liver disease (ascites, jaundice), and symptoms of a pituitary tumor (visual changes, amenorrhea, headache) to narrow down the differential diagnosis of nipple discharge.

The patient should be examined for the presence of any breast masses, asymmetry, and skin changes. After the inspection, palpation should include all four quadrants of each breast and bilateral axillae, supra- and infraclavicular areas to look for masses, swelling, tenderness, and lymphadenopathy. If no spontaneous discharge is visible, the examiner should attempt to extract the discharge by applying even pressure from the periphery toward the nipples (so-called, pressure point exam).

Physiologic discharge is usually bilateral, with clear fluid, involves multiple ducts, and is non-sticky. Pathologic discharge is usually unilateral, spontaneous, varied in appearance, and depending on the cause, involves a single duct. Abnormal discharge is frequently associated with other abnormalities, such as a mass, swelling, redness, dimpled skin, or retracted nipple.[2][4]

Evaluation

The primary goal of evaluation of the nipple discharge in a general outpatient setting or the emergency department is to distinguish patients with benign discharge from those with underlying breast cancer, infection/abscess, or those patients who are at high risk of developing pathologic processes. Those patients, whose age, history, and physical examination suggest the benign cause of their discharge, may be reassured and discharged with outpatient follow-up at their primary care provider's office. However, in patients at high risk for a pathologic process as a cause of their discharge or with worrisome history and physical examination, urgent follow-up with a breast surgeon must be sought.[2][4]

The first step in the evaluation of breast discharge is to rule out whether the discharge is physiological or pathological. Physiological discharge is bilateral and is clear or milky. Pathological discharge is always unilateral and may be bloody. It is hence important to note the color of discharge, whether it occurs spontaneously or occurs with stimulation (which is physiological). Also, associated symptoms are interpreted to make the final diagnosis. 

For patients with physiological discharge, TSH levels, and prolactin levels are measured to rule out systemic causes of nipple discharge. For patients lesser than 40 years of age, routine observation is required. For patients greater than 40 years of age, mammography is indicated. In patients with pathological discharge, mammography and/or ultrasound are performed. If abnormal, a breast biopsy is performed. If normal, then breast MRI, or surgical excision of the lump (if an associated lump is present) is done. Fluid cytology can also be acquired to study the malignant cells in patients with blood discharge, where breast cancer is suspected.[6][4]

In case of a suspected or obvious breast abscess when emergent ultrasound of the breast and a general surgery consultation are needed in the emergency department. Depending on the results of the breast ultrasound and evaluation of the general surgery consultants, the patient may or may not be taken to the operating room for incision and drainage of an abscess. Incision and drainage of a breast abscess in the emergency department are discouraged due to the high pain sensitivity and aesthetic significance of the area, especially when an abscess involves the areola/nipple area. Therefore, appropriate anesthesia is needed, possibly in the operating room, to minimize pain and suffering in a patient, as well as aesthetic considerations.

Treatment / Management

The treatment of breast discharge depends on the etiology. A physiological discharge does not require any treatment. Systemic causes of nipple discharge require specific medications. Benign causes of breast discharge like duct ectasia requires microdochectomy (removal of one duct) or total duct excision (removal of all ducts). Duct papillomas that produce unilateral bloody discharge require microdochectomy. Breast cancer-producing bloody nipple discharge requires surgery and/or chemotherapy or radiation depending on the staging of the disease. Purulent discharge is treated with appropriate antibiotics, but abscesses need incision and drainage and wall biopsy of the abscess.[7][8][9](B2)

Differential Diagnosis

• Intraductal papilloma
• Duct ectasia
• Fibrocystic changes and mastitis
• Intraductal carcinoma
• Paget disease of the nipple

Prognosis

Most nipple discharge is due to an intraductal papilloma and these patients have an excellent outcome when the lesion is excised.