Muhammad Adeel Butt, MD1
1Royal Blackburn Hospital, Blackburn, Lancashire, UK.
Nipple discharge is a presentation commonly seen at breast clinics. It is conventionally evaluated with physical examination and sonography (or mammography). Aim: To investigate the diagnostic value of MRI as an additional imaging tool in the evaluation of potential malignancy in patients presenting with nipple discharge, and to calculate its comparative sensitivity with ultrasound.
Materials and Methods
We conducted a 5-year retrospective evaluation of 949 patients, 85 of whom had nipple discharge, who underwent breast MRI and breast ultrasound (USS) between January 1, 2015, and March 12, 2019. Clinical notes, radiographic reports, and biopsy results were reviewed. Sensitivity, specificity, positive predictive value, and negative predictive value of USS and MRI were calculated.
Of the 85 patients (all female; mean age, 45.33 +/– 12.93 years) with nipple discharge, 11 were found to have biopsy-proven malignancy (invasive ductal carcinoma/ductal carcinoma in situ; 12.94% risk). USS failed to identify 7 malignancies (27.27% sensitivity) while MRI missed 3 malignancies (72.72% sensitivity). USS falsely identified 4 malignancies in 74 patients who had no malignancy (94.59% specificity) while MRI falsely identified only 1 case (98.65% specificity). For patients with negative USS results (U1/U2/U3) or negative MRI results (BI-RADS category 1, 2, or 3), the negative predictive value of USS was 89.74% while that of MRI was 96.05%. The positive predictive values of USS and MRI were 42.86% and 88.88%, respectively.
Compared with USS, MRI has a higher sensitivity, specificity, positive predictive value and predictive value. It will be a valuable addition to the standard nipple discharge evaluation workup to help rule out malignancy.