Varied sonographic appearances of invasive lobular carcinoma. A: Hypoechoic irregular mass with indistinct margins and posterior shadowing (arrow). B: Posterior shadowing without a discrete mass (arrow). C: Poorly defined posterior acoustic shadowing in the parenchyma, but no discrete mass (arrows). D: Large irregular mass with spiculated margins and diffuse posterior acoustic shadowing seen in a patient with a shrinking breast (arrows). E: Diffusely hypoechoic echo pattern without discrete mass (arrows). F: Purely hyperechoic nonmass lesion without shadowing (arrows); no associated finding on mammogram. G: Hyperechoic mass (arrows) with posterior acoustic shadowing. H: Round mass with partially circumscribed margins and a single angular margin (arrow).