Nipple discharge can occur in women who are not pregnant or breastfeeding, especially during the reproductive years. Nipple discharge is not necessarily abnormal, even among postmenopausal women, although it is always abnormal in men. Spontaneous unilateral nipple discharge, regardless of color, is considered abnormal.
Nipple discharge can be serous (yellow), mucinous (clear and watery), milky, sanguineous (bloody), purulent, multicolored and sticky, or serosanguineous (pink). It may occur spontaneously or only in response to breast manipulation.
Pathophysiology of Nipple Discharge
Nipple discharge may be breast milk or an exudate produced by a number of conditions.
Breast milk production in nonpregnant and nonlactating women (galactorrhea) typically involves an elevated level of prolactin, which stimulates glandular tissue of the breast. However, only some patients with elevated prolactin levels develop galactorrhea.
Etiology of Nipple Discharge
Most frequently, nipple discharge has a benign cause (see table Some Causes of Nipple Discharge). Cancer (usually intraductal carcinoma or invasive ductal carcinoma) causes < 10% of cases. The rest result from benign ductal disorders (eg, intraductal papilloma, mammary duct ectasia, fibrocystic changes), endocrine disorders (eg, pituitary tumor), liver disorders, breast abscesses or infections, or use of certain drugs. Of these causes, intraductal papilloma is probably the most common; it is also the most common cause of a bloody nipple discharge without a breast mass.
Some Causes of Nipple Discharge
Cause | Suggestive Findings | Diagnostic Approach |
|---|---|---|
Benign breast disorders | ||
Intraductal papilloma (most common cause) | Unilateral bloody (or guaiac-positive) or serosanguinous discharge | |
Mammary duct ectasia | Unilateral or often bilateral bloody (or guaiac-positive), serosanguinous, or multicolored (purulent, gray, or milky) discharge | |
Fibrocystic changes | A mass, often rubbery and tender, usually in premenopausal women Possibly a serous, green, or white discharge Possibly a history of other masses | |
Abscess or infection | Acute onset with pain, tenderness, or erythema Often fever With abscess, a tender mass and possibly purulent discharge | Clinical evaluation If discharge does not resolve with treatment, evaluation as for breast mass |
Breast cancer | ||
Most often, intraductal carcinoma or invasive ductal carcinoma | May have a palpable mass, skin changes, or lymphadenopathy Sometimes bloody or guaiac-positive discharge | If breast cancer is suspected, evaluation as for breast mass |
Hyperprolactinemia | ||
Many causes (eg, pituitary tumor, hypothyroidism, certain drugs—see table Causes of Hyperprolactinemia) | Often bilateral, milky nonbloody discharge with multiple ducts involved and no masses Possibly menstrual irregularities or amenorrhea If a pituitary lesion is the cause, possibly signs of CNS mass (visual field changes, headache) or other endocrinopathy | Prolactin level, TSH, review of drug use If prolactin or TSH is elevated, MRI of head |
CNS = central nervous system; MRI = magnetic resonance imaging; TSH = thyroid-stimulating hormone. | ||
Evaluation of Nipple Discharge
History
History of present illness should include the following:
Whether the current discharge is unilateral or bilateral
What its color is and whether it is bloody or blood-tinged
How long it has lasted
Whether it is spontaneous or occurs only with nipple stimulation
Whether a mass or breast pain is present
Review of systems should seek symptoms suggesting possible causes, including the following:
Fever: Mastitis or breast abscess
Cold intolerance, constipation, or weight gain: Hypothyroidism
Amenorrhea, infertility, headache, or visual disturbances: Pituitary tumor
Nonlactational mastitis may be periductal mastitis, idiopathic granulomatous mastitis, or tuberculous mastitis.
Past medical history
Physical examination
Physical examination focuses on the breast examination. In male patients, gynecomastia, if present, is noted. The breasts are inspected for symmetry, dimpling of the skin, erythema, swelling, color changes in the nipple and skin, and crusting, ulceration, or retraction of the nipple. The breasts are palpated for masses and evidence of lymphadenopathy in the axillary or supraclavicular region. If there is no spontaneous discharge, the area around the nipples is systematically palpated to try to stimulate a discharge and to identify any particular location associated with the discharge.
SCIENCE PHOTO LIBRARY
A bright light and magnifying lens can help assess whether the nipple discharge is uniductal or multiductal.
Red flags
Certain findings are of particular concern:
Palpable breast mass or skin changes
Bloody discharge
Unilateral discharge
Spontaneous discharge
Age ≥ 40
Male sex
Interpretation of findings
If a mass is present or discharge is guaiac-positive, even if bilateral, cancer must be considered.
Discharge that is bilateral and/or multiductal and guaiac-negative suggests an endocrine cause.
Presence of any of the following requires follow-up with a surgeon who is experienced with breast disorders:
A breast mass
A bloody (or guaiac-positive) discharge
A spontaneous unilateral discharge
History of an abnormality on a mammogram or a breast ultrasound
For other suggestive findings, see table Some Causes of Nipple Discharge.
Testing
If endocrine causes are suspected, the following are measured:
Prolactin level
Thyroid-stimulating hormone (TSH) level
If discharge is guaiac-positive, the following is done:
Cytology
If there is a palpable breast mass, evaluation may include
Ultrasonography, cyst aspiration, or mammography
If there is no mass but cancer is otherwise suspected or if other tests are indeterminate, the following is done:
Mammography
If results of imaging or cytology (of cyst aspirate) are abnormal, image-guided biopsy is done.
If mammography and ultrasonography do not identify a source and the discharge is spontaneous and comes from a single duct or breast, evaluation may include
Ductography (contrast-enhanced imaging of the milk duct) or image-guided biopsy
Treatment of Nipple Discharge
Treatment of a nipple discharge is based on the cause. If imaging identifies a lesion, core needle biopsy is done.
Breast cancer is treated as appropriate.
Intraductal papillomas, which are the most common cause of bloody nipple discharge, can be excised after diagnosis with needle biopsy. This procedure prevents further nipple discharge and rules out the small possibility of a coexisting cancer. Symptomatic, palpable papillomas or those with associated atypia should be excised. Incidentally discovered papillomas do not require excision.
Hyperprolactinemia is treated with drugs or surgical removal of a pituitary tumor. Liver disorders are treated as appropriate for the specific disorder.
Key Points
Nipple discharge is most often benign.
Bilateral, multiductal, guaiac-negative discharge is usually benign and has an endocrine etiology.
Spontaneous, unilateral discharge requires diagnostic testing; this type of discharge may be cancer, particularly if it is bloody (or guaiac-positive).
Presence of a breast mass, a bloody (or guaiac-positive) discharge, or history of an abnormality on a mammogram or an ultrasound scan requires follow-up with a surgeon who is experienced with breast disorders.
