What is the approach to evaluating nipple discharge?

Workup of Nipple Discharge

Begin by determining if the discharge is physiologic or pathologic—physiologic discharge requires no imaging, while pathologic discharge mandates age-appropriate imaging with mammography/ultrasound and potential surgical referral if imaging is negative but discharge persists. 1, 2

Step 1: Classify the Discharge Type

Physiologic Discharge (No Imaging Needed)

• Bilateral presentation from multiple ducts 1
• White, green, yellow, or milky in color 2
• Occurs only when provoked (not spontaneous) 1
• Has no association with breast cancer 1

Pathologic Discharge (Requires Full Workup)

• Spontaneous occurrence 2
• Unilateral presentation 2
• Single duct origin 2
• Bloody, serous, or serosanguineous appearance 2
• Associated with underlying malignancy in 3-29% of cases overall, but risk varies significantly by age and sex 1

Critical pitfall: Do not dismiss non-bloody discharge as benign—serous and colored discharge carry similar malignancy risk to bloody discharge 2, 3

Step 2: Age and Sex-Stratified Imaging Algorithm

Women ≥40 Years

• Diagnostic mammography or digital breast tomosynthesis (DBT) as initial study 1, 2
• Complementary ultrasound of both breasts with special attention to retroareolar region 1, 2
• Repeat mammography if prior study was >6 months ago 1
• Malignancy rate: 10% for ages 40-60, 32% for age >60 2

Women 30-39 Years

• Either mammography/DBT or ultrasound can serve as initial examination 1
• Add the complementary modality regardless of which is performed first 1

Women <30 Years

• Ultrasound as initial and primary examination 1
• Add mammography/DBT only if ultrasound shows suspicious findings due to low cancer incidence and radiation risk 1

Men ≥25 Years

• Mammography/DBT with complementary ultrasound 1, 4
• Exceptionally high malignancy risk: 23-57% of nipple discharge cases 2, 4
• Requires the same rigorous imaging evaluation as females 2

Men <25 Years

• Initial ultrasound with mammography added as indicated 1

Step 3: Optimize Ultrasound Technique

• Use standoff pad or abundant warm gel 2
• Apply peripheral compression and rolled-nipple techniques 2
• Ultrasound is more sensitive than mammography but less specific 1, 2

Step 4: Management Based on Initial Imaging Results

If Lesion Identified on Imaging

• Perform image-guided core needle biopsy (preferred over fine-needle aspiration) 1, 2, 4
• Use ultrasound guidance for localization when possible 2, 4

If Initial Imaging is Negative but Discharge Persists

• Consider MRI with sensitivity up to 96% and negative predictive value of 87-98.2% 1, 5
• Consider ductography (galactography) or DBT-ductography with improved sensitivity over conventional galactography 2
• Surgical consultation for central duct excision or selective duct excision if imaging remains negative 2

Key reassurance: A negative mammogram reduces carcinoma risk to 3%, while negative mammogram AND ultrasound reduce risk to approximately 0% 1

Step 5: Common Pathologies to Expect

Benign Causes (Most Common)

• Intraductal papilloma (35-48%): Look for asymmetrically dilated ducts, circumscribed subareolar mass, or grouped microcalcifications on mammography 1, 2
• Ductal ectasia (17-36%): Second most common cause 1, 2

Malignant Causes

• Overall malignancy rate: 5-21% in pathologic discharge 2
• Mammography sensitivity for malignancy: 15-68% (do not rely on mammography alone) 2, 4

Critical Pitfalls to Avoid

• Never skip imaging in males—they have exceptionally high malignancy rates requiring aggressive workup 2, 4
• Do not rely on mammography alone—sensitivity is only 15-68% 2
• Do not dismiss serous or colored discharge—these carry similar malignancy risk to bloody discharge 2, 3
• Beware false-positive ultrasound results from volume averaging with ductal wall, intraductal/periductal fibrosis, or adherent blood clots 1