Mammographic and sonographic features of triple-negative invasive carcinoma of no special type.

The aim of this study was to compare the mammography, ultrasound (US) and histologic features of triple-negative (TN) invasive carcinoma of no special type (NST) to non-TN invasive carcinoma of NST. The second aim was to assess whether the distinct imaging characteristics of TN breast cancer would persist after controlling for the histologic features. A total of 344 invasive carcinomas of NST in 337 patients from January 2007 to February 2008 were included in this study. Two radiologists retrospectively reviewed the mammography and US findings using the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) lexicon and our institution's criteria. On mammography, TN invasive carcinoma of NST most commonly presented as a mass with round shape and non-spiculated margin. On US, it was more likely to have internal hypoechogenicity, an abrupt boundary and posterior acoustic enhancement. TNBC lacked major suspicious imaging findings such as an irregular shape, spiculated margin and calcification.