Risk of malignancy in palpable solid breast masses considered probably benign or low suspicion: implications for...

To determine whether solid palpable breast masses with benign sonographic features have less than 2% incidence of malignancy, allowing management by surveillance instead of biopsy.

With Institutional Review Board approval, sonography reports of palpable solid breast masses from January 1, 2006, to December 31, 2009, prospectively classified as probably benign (American College of Radiology Breast Imaging Reporting and Data System [BI-RADS] 3) or low suspicion (BI-RADS 4A) were reviewed. Category 4A lesions were included because many palpable benign-appearing masses at our institution are classified as 4A for palpability. The BI-RADS categories were correlated with outcome data, comprising tissue diagnosis, imaging stability for at least 24 months, or decrease/resolution during imaging surveillance.

The study population included 440 lesions in 381 patients (mean age, 31.0 years; range, 15-68 years). A total of 161 lesions were prospectively classified as BI-RADS 3 and 279 as BI-RADS 4A. A total of 295 lesions (67%) had biopsy within 4.5 months of presentation, with 3 invasive malignancies; 145 of 440 lesions (33%) underwent surveillance. Forty-one lesions were considered benign for the following reasons: stability for at least 24 months (n = 28), benign tissue diagnosis during surveillance (n = 5), and decrease/resolution during follow-up (n = 8). The malignancy rate in lesions with adequate follow-up or biopsy was 3 of 336 (0.9%). All 3 malignancies occurred in women older than 40 years.

The incidence of malignancy in palpable solid breast masses classified as BI-RADS 3 or 4A in this study was less than 2%. In young women, surveillance rather than biopsy is appropriate for BI-RADS 3 palpable lesions. Palpability does not merit a BI-RADS 4A classification in solid masses with otherwise benign-appearing morphologic features, particularly in young women.