Diagnostic accuracy of breast MRI for patients with suspicious nipple discharge and negative mammography and ultrasound: a prospective study

Objectives To evaluate the diagnostic accuracy of breast MRI in identifying lesions requiring excision for patients with suspicious nipple discharge but normal mammograms and ultrasounds. Methods Between September 2013 and May 2019, 106 female participants (mean age 57.9 years) were consecutively included in this prospective multicenter study; 102 were retained for analysis. MRI was considered negative in the absence of suspicious enhancement and positive in cases of ipsilateral abnormal enhancement (BI-RADS 3 to 5). Final diagnoses were based on histological findings of surgical or percutaneous biopsies or at 1-year follow-up. We considered all lesions requiring excision found on pathology (papilloma, atypia, nipple adenomatosis, or cancer) as positive results. We considered spontaneous resolution of the discharge at 1 year as a negative result. Results MRI showed ipsilateral abnormal enhancement in 54 patients (53%) revealing 46 lesions requiring excision (31 benign papillomas, 5 papillomas with atypia, 2 nipple adenomatosis, and 8 cancers) and 8 benign lesions not requiring excision. No suspicious enhancement was found in the remaining 48 participants (47%). Forty-two were followed up at 1 year with spontaneous resolution of the discharge and six underwent surgery (revealing 2 benign papillomas). MRI diagnostic accuracy for the detection of a lesion requiring excision was as follows: sensitivity 96%, specificity 85%, positive predictive value 85%, and negative predictive value 96%. Conclusion In patients with suspicious nipple discharge and normal mammogram and ultrasound, MRI demonstrates excellent performance to identify lesions for which excision is required. Normal MRI indicates it is safe to propose follow-up only management, thus avoiding unnecessary duct excision.