Ultrasound characteristics of histologically proven grade 3 invasive ductal breast carcinoma

High-grade invasive ductal carcinoma (IDC) may paradoxically display features similar to benign breast masses. This study analysed the ultrasound features of histologically proven cases of grade 3 IDC. At North Western BreastScreen Victoria, from 4 February 1993 to 30 September 2002, 181 cases of grade 3 IDC that had ultrasound evaluation were available for retrospective analysis. For each tumour, four features were assessed: margin, attenuation characteristics, echotexture and depth versus width ratio. Eighty-seven per cent of tumours had an aggressive margin with an echogenic rind, microlobulation or angular margins. However, 11% had a well-defined smooth margin. The classic sonographic malignant feature of posterior shadowing was present in only 30%, whereas the tissues posterior to the lesion remained isoechoic in 48% and showed posterior enhancement in 11%. Six per cent of the tumours were isoechoic and difficult to appreciate on ultrasound. The best feature to characterize lesions as malignant was the margin of the lesion. To ensure that malignant lesions are correctly categorized, it is important that interfaces between the tumour and adjacent breast parenchyma are meticulously evaluated in a real-time fashion rather than viewed as a single still image.