What is the evaluation approach for a patient presenting with nipple discharge?

Evaluation of Nipple Discharge

All patients with pathologic nipple discharge should undergo diagnostic mammography and ultrasound as the initial imaging evaluation, with breast MRI reserved for cases where these are negative but clinical suspicion remains high. 1, 2

Step 1: Distinguish Pathologic from Physiologic Discharge

Pathologic discharge requires full workup and has the following characteristics (any single feature qualifies): 1, 2

• Spontaneous (occurs without manipulation)
• Unilateral
• Single duct origin
• Serous or bloody appearance

Physiologic discharge requires no imaging beyond routine screening and has these features: 1, 2

• Bilateral
• Multiple ducts
• Only with provocation/manipulation
• White, green, or yellow color

Critical pitfall: Do not dismiss discharge in men—malignancy risk is 23-57% in males with nipple discharge, compared to 11-16% in women. 3, 2

Step 2: Assess Malignancy Risk

Age-stratified malignancy risk for pathologic discharge: 3, 1, 2

• <40 years: 3% risk
• 40-60 years: 10% risk
• >60 years: 32% risk

High-risk features that dramatically increase cancer probability: 3

• Palpable mass present: 61.5% malignancy rate (vs. 6.1% without mass)
• Male sex: 23-57% malignancy rate
• Age >60 years: 32% malignancy rate

Step 3: Imaging Algorithm for Pathologic Discharge

First-Line: Diagnostic Mammography

• Perform diagnostic mammography of the symptomatic breast (bilateral if no recent screening within 6 months) 3, 1
• Sensitivity 15-68%, specificity 38-98% for malignancy detection 1
• Include craniocaudal and mediolateral oblique views with additional views as indicated 3

Second-Line: Targeted Ultrasound

• Evaluate the retroareolar region of symptomatic breast with ultrasound 3, 1
• Use standoff pad or abundant warm gel to eliminate acoustic shadows from nipple 3
• Sensitivity 63-100% for detecting intraductal lesions 1
• Can serve as initial modality if patient recently had mammogram or is pregnant 1

Third-Line: Breast MRI (if mammography and ultrasound negative)

• MRI is now preferred over ductography due to superior positive and negative predictive values 3
• Sensitivity 86-100% for detecting causes of pathologic discharge 1
• Detects underlying abnormalities in 19-96% of cases when conventional imaging is negative 3
• Can identify posterior lesions >3 cm from nipple that ductography misses 3

Important caveat: Up to 20% of lesions causing pathologic discharge are located >3 cm beyond the nipple, highlighting why thorough preoperative imaging is essential before considering surgical excision. 3

Step 4: Management Based on Findings

If suspicious lesion identified on imaging: 1

• Perform image-guided core biopsy (preferred over fine needle aspiration)
• Core biopsy provides definitive tissue diagnosis for pathologic assessment

If all imaging is negative but pathologic discharge persists: 3

• Consider breast MRI if not yet performed
• Surgical duct excision may be considered, though recent evidence suggests surveillance may be reasonable given MRI's high negative predictive value 4
• Major duct excision is no longer automatic standard for all pathologic discharge cases 1

Critical consideration for women of childbearing age: Major duct excision may be undesirable as it can affect future breastfeeding capability. 3

Common Etiologies

The most frequent causes of pathologic nipple discharge are: 3, 1

• Intraductal papilloma: 35-48% of cases
• Duct ectasia: 17-36% of cases
• Malignancy: 5-21% overall (10% at age 40,32% at age >60)