Findings of contrast-enhanced ultrasonography with Sonazoid for cholangiocellular adenoma in three dogs

Contrast-enhanced ultrasonography (CEUS) is useful to distinguish benign and malignant focal liver lesions in dogs. Cholangiocellular adenoma is an extremely rare benign tumor in dogs and has not been examined using CEUS with Sonazoid. The aim of this study was to describe findings of CEUS with Sonazoid in three dogs with cholangiocellular adenoma. All three dogs showed contrast defects in the Kupffer phase and these findings mimicked malignant neoplasia during the Kupffer phase. Moreover, all dogs showed early washout and hypoechoic lesions relative to the surrounding normal liver parenchyma in the portal phase. To our knowledge, this is the first study to report that CEUS findings of cholangiocellular adenoma with Sonazoid mimicked malignancy in three dogs.