From the Guidelines
The workup of unilateral non-bloody nipple discharge should begin with a thorough clinical history and physical examination, followed by diagnostic mammography or digital breast tomosynthesis (DBT) as the initial imaging study, depending on the patient's age and other factors, as recommended by the American College of Radiology 1. The physical exam should assess for masses, skin changes, and attempt to localize the discharge to a specific duct.
- Determine if the discharge is truly unilateral and spontaneous, as these features increase concern for underlying pathology.
- Diagnostic mammography or DBT is usually appropriate for the initial imaging of pathologic nipple discharge in adult male or female patients 40 years of age or older, as well as in transfeminine (male-to-female) patients 30 years of age or older 1.
- Breast US is complementary to DBT and diagnostic mammography and may be performed during the same patient encounter or in close approximation to one another to better characterize the disease process 1.
- If imaging is negative but clinical suspicion remains high, a ductogram (galactogram) may help visualize the affected duct system, or image-guided core biopsy may be necessary to obtain a tissue diagnosis 1.
- Nipple discharge cytology can be performed but has limited sensitivity, and major duct excision remains the reference standard to exclude malignancy in patients with unremarkable imaging 1.
- The most common causes of unilateral non-bloody discharge include intraductal papilloma, duct ectasia, and fibrocystic changes, though malignancy must always be considered, especially in women over 40 or those with other risk factors 1.
- While most cases are benign, thorough evaluation is essential to rule out breast cancer, which accounts for approximately 5-15% of cases of unilateral spontaneous nipple discharge.
- Image-guided CNB is equally useful in male patients for obtaining tissue diagnosis and assisting in patient management, but is not indicated as the initial examination to evaluate pathological nipple discharge 1.
From the Research
Unilateral Non-Bloody Nipple Discharge Workup
- The workup of unilateral non-bloody nipple discharge involves a detailed clinical history and physical examination to classify the discharge as pathologic or physiologic 2
- Pathologic discharge is typically spontaneous, unilateral, or associated with a breast mass, and requires diagnostic imaging 2
- Mammography and ultrasound are commonly used as first-line imaging methods, but mammography has low sensitivity in cases of nipple discharge due to small, retroareolar lesions without calcifications 3
- Ultrasound is important for detecting intraductal lesions in the retroareolar region, and its sensitivity and specificity make it a valuable tool in the diagnostic process 3
- Magnetic resonance imaging (MRI) may be recommended in cases of suspicious nipple discharge with normal mammography and ultrasound findings, as it can detect abnormalities not seen on other imaging modalities 4, 3
- The clinical examination is essential in detecting malignancy, and multiductal discharge is not necessarily related to malignancy 5
- Cytology may have a limited role in detecting malignancy, with low positive predictive values for the presence of red blood cells and epithelial cells 5
Imaging Modalities
- Mammography: low sensitivity in cases of nipple discharge, but useful for detecting calcifications and larger lesions 3, 5
- Ultrasound: valuable for detecting intraductal lesions in the retroareolar region, with good sensitivity and specificity 3
- MRI: useful in cases of suspicious nipple discharge with normal mammography and ultrasound findings, can detect abnormalities not seen on other imaging modalities 4, 3