To investigate the malignancy rate of retroareolar masses and intraductal abnormalities discovered in asymptomatic females during screening whole breast ultrasound (US-S) and determine if biopsy can be avoided.
Methods:: This is a HIPAA compliant retrospective study. Our radiology electronic medical records were searched for the phrases "retroareolar mass" or "intraductal mass" combined with "screening whole breast ultrasound" performed between 10/1/2009 and 5/30/2015. Inclusion criteria included retroareolar masses in asymptomatic females with normal mammography, mammographically dense breast tissue and imaging or biopsy follow-up.
Results:: 1136 charts were reviewed. 87 BI-RADS 3 and 4 retroareolar findings were included in final analysis. The average lesion size was 9.5 mm (range 4-28 mm). 47/87 lesions were classified as BI-RADS 3 and 40/87 BI-RADS 4. Of the 47 BI-RADS 3 lesions, 36 were stable on follow-up; 6 benign lesions were biopsied at patients' request; and 5 biopsied due to suspicious interval change on follow-up imaging, including 4 benign lesions and a 5 mm Grade 2 ductal carcinoma in situ . 3/40 BI-RADS 4 lesions were not biopsied and stable at follow-up; 37/40 lesions underwent benign biopsy. The malignancy rate of BI-RADS 3 and 4 lesions was 2.1% [CI (0.4-11.1)] and 0% [CI (0.0-8.8)], respectively. The overall combined malignancy rate was 1/87 [1.1%, CI (0.2-6.2)].
Conclusion:: The malignancy rate for BI-RADS 3 and 4 retroareolar masses and intraductal abnormalities detected on US-S is low (<2%).
Advances in knowledge:: Careful imaging surveillance in lieu of biopsy of these lesions may be appropriate in asymptomatic females with negative mammography.