Nipple Discharge Imaging Evaluation with Mammography, Ultrasound, Galactography, and MRI

Rationale and Objective: To determine the diagnostic yield of various imaging tests used to evaluate nipple discharge. Materials and Methods: A single institution, IRB-approved, retrospective study was performed of 320 consecutive patients presenting with nipple discharge. Imaging and pathology were reviewed to determine the yield for malignancy, atypical high-risk lesions (HRLs), and intraductal papillomas (IDPs). Results: Of the 320 patients, pathology or follow up confirmed 40 breast malignancies (40/320, 12.5%),14 atypical HRLs (14/320, 4.4%), 71 IDPs (71/320, 22.2%), 48 other benign pathologies (48/320,15.0%), and 147 unknown but benign cases (147/320, 45.9%). Physiologic discharge characteristics were observed in a minority of malignant cases: nonspontaneous (4/40, 10.0%); neither bloody nor clear (4/40, 10.0%); bilateral (3/40, 7.5%). Malignancy was associated with older age (p < 0.001) and bloody discharge (odds ratio 6.5, p < 0.0001). The combination of digital mammography and ultrasound had a 93% sensitivity and a 98% NPV, while contrast enhanced MRI (CE-MRI) had a 100% sensitivity and a 100% NPV for malignancy. Only three galactography examinations were performed among the malignant cohort, with minimal contribution (1 of 3) to the diagnostic evaluation. In this case, galactography findings helped determine imaging-pathology discordance, prompting a recommendation for surgical excision and subsequently a malignant diagnosis. Conclusion: The combination of mammography and ultrasonography detected 93% of breast malignancies associated with nipple discharge and had a 98% NPV for malignancy. The value of CE-MRI is its ability to detect the remaining malignancies, not detected on mammography or ultrasound, and its ability to obviate the need for surgical duct excision.