Ultrasound Morphology of Invasive Lobular Breast Cancer is Different Compared with Other Types of Breast Cancer

The aim of this study was to evaluate the ultrasound (US) morphology of invasive lobular breast carcinomas (ILC) in comparison to that of invasive tumors of other histologic differentiation (TOD). Images of 406 breast lesions were included in this retrospective study. A total of 10 US criteria (shape, orientation, echogenicity, echo pattern, calcifications, margin, margin contour, lesion boundary, surrounding tissue and posterior acoustic features) were defined and determined. Tumors were stratified into ILC (n = 69) vs. TOD (n = 337). The correlation between the sonographically and pathologically measured size of the tumors was analyzed. Irregular shape was found in 88% of ILC vs. 67% of TOD (p < 0.001). Margins were indistinct in 94% of ILC compared to 76% of TOD (p = 0.001). Posterior shadowing was observed in 84% of ILC and 58% of TOD (p = 0.001). Irregular margin contour, hyper- or isoechoic pattern and architectural distortion were more frequent in ILC. Underestimation of tumor size by US was significantly more frequent in ILC (5.4 +/- 12.2 mm) than in TOD (1.4 +/- 12.0 mm) (p = 0.015). In summary, we found that histologic differentiation significantly influences ultrasonographic appearance of breast cancer. The underestimation of tumor size of ILC might compromise the operative strategy.