Nipple Discharge

Nipple Discharge

In order of decreasing frequency, the following are the most common causes of nipple discharge in the nonlactating breast: duct ectasia, intraductal papilloma, and carcinoma. The important characteristics of the discharge and some other factors to be evaluated by history and physical examination are as follows:

1. Nature of the discharge (serous, bloody, or other).

2. Association with a mass.

3. Unilateral or bilateral.

4. Single or multiple duct discharge.

5. Discharge is spontaneous (persistent or intermittent) or must be expressed.

6. Discharge produced by pressure at a single site or by general pressure on the breast.

7. Relation to menses.

8. Premenopausal or postmenopausal.

9. Patient taking contraceptive pills or estrogen.

Spontaneous, unilateral, serous or serosanguineous discharge from a single duct is usually caused by an intraductal papilloma or, rarely, by an intraductal cancer. A mass may not be palpable. The involved duct may be identified by pressure at different sites around the nipple at the margin of the areola. Bloody discharge is suggestive of cancer but is more often caused by a benign papilloma in the duct. Cytologic examination may identify malignant cells, but negative findings do not rule out cancer, which is more likely in women over age 50 years. In any case, the involved duct—and a mass if present—should be excised. A ductogram (a mammogram of a duct after radiopaque dye has been injected) is of limited value since excision of the suspicious ductal system is indicated regardless of findings. 

Ductoscopy, evaluation of the ductal system with a small scope inserted through the nipple has been studied as a means of identifying intraductal lesions but is not practical in the clinical setting since it does not replace pathologic diagnosis.

In premenopausal women, spontaneous multiple duct discharge, unilateral or bilateral, most noticeable just before menstruation, is often due to fibrocystic condition. Discharge may be green or brownish. Papillomatosis and ductal ectasia are usually detected only by biopsy. If a mass is present, it should be removed.

A milky discharge from multiple ducts in the nonlactating breast may occur from hyperprolactinemia. Serum prolactin levels should be obtained to search for a pituitary tumor. 

Thyroid-stimulating hormone (TSH) helps exclude causative hypothyroidism. Numerous antipsychotic drugs and other drugs may also cause a milky discharge that ceases on discontinuance of the medication.

Oral contraceptive agents or estrogen replacement therapy may cause clear, serous, or milky discharge from a single duct, but multiple duct discharge is more common. In the premenopausal woman, the discharge is more evident just before menstruation and disappears on stopping the medication. If it does not stop and is from a single duct, exploration may be considered.

A purulent discharge may originate in a subareolar abscess and require removal of the abscess and the related lactiferous sinus.

When localization is not possible, no mass is palpable, and the discharge is nonbloody, the patient should be reexamined every 3 or 4 months for a year, and a mammogram and an ultrasound should be performed. Although most discharge is from a benign process, patients may find it annoying or disconcerting. Cytologic examination of the nipple discharge for exfoliated cancer cells may rarely be helpful in determining a diagnosis. 

To eliminate the discharge, proximal duct excision can be considered both for treatment and diagnosis.

Barghav RK et al. The value of clinical characteristics and breast imaging studies in predicting a histopathologic diagnosis of cancer or high-risk lesion in patients with spontaneous nipple discharge. Am J Surg. 2007 Jan;193(1):141–2.

Escobar PF et al. The clinical applications of mammary ductoscopy. Am J Surg. 2006 Feb;191(2):211–5.

Sauter ER et al. Nipple aspirate fluid color is associated with breast cancer. Cancer Detect Prev. 2006;30(4):322–8.