Shear-wave sonoelastographic features of invasive lobular breast cancers

AIM: To evaluate shear-wave elastographic (SWE) and related gray-scale features of pure invasive lobular breast carcinoma (ILC) and compare them with invasive ductal breast cancers (IDC). METHODS: Quantitative SWE features of mean (El-mean), maximum (El-max), minimum (El-min) elasticity values of the stiffest portion of the mass, and lesion-to-fat elasticity ratio (E-ratio) were measured in 40 patients with pure ILC and compared with 75 patients with IDC. Qualitative gray-scale features of lesion size, echogenicity, orientation, and presence of distal shadowing were determined and compared between the groups. RESULTS: ILC were significantly larger than IDC (P = 0.008) and exhibited significantly higher El-max (P = 0.015) and higher El-mean (P = 0.008) than IDC. ILC were significantly more often horizontally oriented, while IDC were significantly more often vertically oriented (P < 0.001); ILC were significantly more often hyperechoic than IDC (P < 0.001). Differences in stiffness between ILC and IDC determined by quantitative SWE parameters were present only in small tumors (≤1.5 cm in size), ie, small ILC had significantly higher El-max (P = 0.030), El-mean (P = 0.014), and El-min (P = 0.045) than small IDC, while tumors larger than 1.5 cm had almost equal stiffness, without significant differences between the groups. CONCLUSION: Specific histopathologic features of ILC are translated into their qualitative sonographic and quantitative sonoelastographic appearance, with higher stiffness of small ILC compared to small IDC. Gray-scale and sonoelastographic features may help in diagnosing ILC.