Intraductal mass on breast ultrasound: final outcomes and predictors of malignancy

The purpose of this study was to retrospectively investigate the final outcomes of intraductal masses on breast ultrasound and determine the clinical and radiologic variables associated with malignancy.

A database search (2006-2008) was performed to find patients who had an intraductal mass on breast ultrasound. Histopathologic or ultrasound follow-up (> 24 months) data were available from 147 women (mean age, 49.8 years) with 163 intraductal masses. Clinical and radiologic variables (age, symptom, personal and family history, lesion size, and distance from the nipple) and pathologic results were collected. Ultrasound features of the intraductal masses were reviewed by two radiologists in consensus and classified into three morphologic types: mass incompletely filling the duct, mass completely filling the duct, and mass extending outside the duct. Involvement of a branch duct was also analyzed. Associations between variables and final outcomes were analyzed using chi-square tests and Student t tests.

Thirteen (8%) of the 163 intraductal masses were malignant (10 ductal carcinomas in situ and three invasive ductal carcinomas). Malignancy was significantly associated with symptoms (p = 0.008) and personal history of breast cancer (p < 0.007). Malignant intraductal masses were larger than benign intraductal masses (1.4 cm vs 0.9 cm, p = 0.02). Malignant intraductal masses tended to fill the duct more completely or extend outside the duct (p < 0.001), and they more frequently involved the branch duct (p < 0.001) than did the benign intraductal masses.

Our study showed that 8% of intraductal masses are malignant. Symptoms, personal history, lesion size, and ultrasound features can be possible predictors of malignancy.