Ductal carcinoma in situ diagnosed using an ultrasound-guided 14-gauge core needle biopsy of breast masses: can underestimation be predicted preoperatively?

PURPOSE: This study was designed to determine the rate of ductal carcinoma in situ (DCIS)underestimation diagnosed after an ultrasound-guided 14-gauge core needle biopsy (US-14G-CNB) of breast masses and to compare the clinical and imaging characteristics between trueDCIS and underestimated DCIS identified following surgical excision. METHODS: Among 3,124 US-14G-CNBs performed for breast masses, 69 lesions in 60 patients were pathologically-determined to be pure DCIS. We classified these patients according to the final pathology after surgical excision as those with invasive ductal carcinoma (underestimated group) and those with DCIS (non-underestimated group). We retrospectively reviewed and compared the clinical and imaging characteristics between the two groups. RESULTS: Of the 69 lesions, 21 were shown after surgery to be invasive carcinomas; the rateof DCIS underestimation was 30.4%. There were no statistically significant differences withrespect to the clinical symptoms, age, lesion size, mammographic findings, and ultrasonographic findings except for the presence of abnormal axillary lymph nodes as detected on ultrasound. The lesions in 2 patients in the non-underestimated group (2/41, 4.9%) and 5 patients in the underestimated group (5/19, 26.3%) were associated with abnormal lymph nodes on axillary ultrasound, and the presence of abnormal axillary lymph nodes on ultrasound was tatistically significant (P=0.016). CONCLUSION: We found a 30.4% rate of DCIS underestimation in breast masses based on a US-14G-CNB. The presence of abnormal lymph nodes as detected on axillary ultrasound may be useful to preoperatively predict underestimation.