Objective  To evaluate the clinical value of ultrasound-guided core-needle biopsy (US-CNB) in the diagnosis of breast lesions under categories 4A to 4C of the second edition of the Breast Imaging Reporting and Data System (BI-RADS) ultrasound lexicon.

  Methods  The pathological characteristics of 355 patients with breast masses who underwent US-CNB in the Tianjin Medical University Cancer Institute and Hospital from March 2015 to October 2015 were retrospectively analyzed. Each patient was subjected to postoperative pathological examination to confirm diagnosis.

  Results  According to the US-CNB results, of the 355 patients, 235 were diagnosed with breast cancer, and 120 had benign lesions. Through postoperative pathological examination, 41 of the patients with benign lesions were confirmed to have breast cancer. The specificity of the US-CNB was 100% in all the categories of breast masses. The sensibilities of breast masses under BI-RADS categories 4A, 4B, and 4C were 62.50%, 82.46%, and 89.73%, respectively. The accuracies of the US-CNB in 4A, 4B, and 4C were 84.62%, 87.01%, and 90.74%, correspondingly. Of the 41 patients with false-negative results, 14 had intraductal carcinoma, 5 had intraductal papillary carcinoma, 3 had mucinous carcinoma, and 19 had invasive ductal carcinoma.

  Conclusion  US-CNB is a safe, reliable, and accurate early diagnostic method for breast masses under the 4B and 4C categories. However, the sensibility of US-CNB was extremely low in patients with breast masses under the 4A category. Thus, final diagnosis should be accomplished by combining US-CNB with mammography, MRI, or other testing methods. Meanwhile, US-CNB is not recommended for patients with intraductal papillary neoplasms diagnosed through ultrasonography.