Role of breast magnetic resonance imaging (MRI) in patients with unilateral nipple discharge: preliminary study.

Purpose: This study was performed to assess the role of magnetic resonance imaging (MRI) in patients with unilateral nipple discharge.
Materials and Methods: Forty-four patients with bloody or serosanguineous nipple discharge and negative mammographic findings (35/44 cases) underwent MRI for evaluation of breast ducts. Ultrasonography, negative in 18 patients, identified 26 cases of ductal ectasia (12 simple, nine with solid intraductal echoes and wall thickening, five with inhomogeneous parenchyma). Galactography was negative in three patients and positive in nine. Nineteen patients were followed up by clinical examination, ultrasonography, and cytological evaluation of nipple discharge (6-12 months); three patients underwent excisional biopsy, ten core biopsy and 12 cytological biopsy (followed by excisional biopsy).
Results: MRI identified 25 enhancing lesions Breast Imaging Reporting and Data Systems (BI-RADS) 3 or 4) and confirmed the galactographic findings (ductal ectasia, intraluminal filling defects). Five papillomatoses appeared as patchy, homogeneous enhancing areas, 15 intraductal papillomas as areas with well-defined margins and type II time-intensity curves, and two atypical ductal hyperplasias as diffuse nodular enhancement. One micropapillary ductal carcinoma in situ (DCIS), one papillary carcinoma and one infiltrating ductal carcinoma (IDC) were visualised as two segmental areas of enhancement and one mass-like enhancement with poorly defined margins (BI-RADS 4). The follow-up was negative, showing no pathological enhancement (BI-RADS 1) in 12 patients and benign enhancement (BI-RADS 2) in seven.
Conclusions: Breast MRI can be considered a valuable examination in the diagnosis of suspected ductal disease and an alternative to galactography when the latter cannot be used.