Most Common Causes of Nipple Bleeding in Adults
Intraductal papilloma is the most common cause of pathologic nipple discharge (including bloody discharge), accounting for 35-48% of cases, followed by duct ectasia at 17-36%. 1
Benign vs. Malignant Etiologies
The vast majority of bloody nipple discharge stems from benign conditions, but malignancy must be excluded:
- Benign causes dominate the differential, with intraductal papilloma being the leading etiology (35-48% of pathologic discharge cases), followed by duct ectasia (17-36%) 1
- Malignancy risk ranges from 5-21% in patients with pathologic nipple discharge who undergo biopsy 1
- The malignancy rate is significantly higher in men presenting with nipple discharge (23-57%) compared to women (11-16%) 2, 3
Age-Stratified Malignancy Risk
Age is a critical risk factor that should guide your clinical suspicion:
- Under 40 years: 3% malignancy risk 1, 2
- 40-60 years: 10% malignancy risk 1, 2
- Over 60 years: 32% malignancy risk 1, 2
This dramatic age-related increase means you should have heightened concern for malignancy in older patients, even with otherwise reassuring features.
Specific Pathologic Entities
When intraductal lesions are identified, the distribution includes:
- Intraductal papilloma (most common benign cause) 4, 5
- Duct ectasia (second most common) 4, 6
- Ductal carcinoma in situ (most common malignant cause when cancer is present) 6, 7
- Invasive ductal carcinoma (less common presentation with discharge) 4
- Papillomatosis 4
Clinical Features That Increase Malignancy Risk
Bloody or serosanguineous discharge has the highest association with intraductal lesions (83.3% and 76.2% respectively), compared to serous discharge (69.2%) 5. Additional high-risk features include:
- Spontaneous discharge (not provoked) 1, 3
- Unilateral presentation 1, 3
- Single-duct origin 1, 3
- Presence of palpable mass (increases malignancy rate to 61.5% vs. 6.1% without mass) 1
- Male sex (57% malignancy rate in one series) 1
Common Pitfall
Do not assume bloody discharge is automatically cancer—remember that benign papillomas and duct ectasia together account for 52-84% of pathologic discharge cases, far exceeding the 5-21% malignancy rate 1. However, even with negative imaging, surgical duct excision should be performed for pathologic discharge to definitively exclude malignancy, as imaging can miss up to 33% of malignant lesions 2, 5.