A case of well-differentiated cholangiolocellular carcinoma visualized with contrast-enhanced ultrasonography using Sonazoid.

We here report the first case of cholangiolocellular carcinoma (CoCC) visualized with contrast-enhanced ultrasonography (CEUS) using a second-generation contrast agent, Sonazoid. A 76-year-old man was admitted to our hospital for evaluation of a hepatic tumor. The tumor was described as having hyper-enhancement in the early phase and persistent enhancement in the late phase by contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI), as well as hypervascularity by angiography. CEUS assessment of the nodule showed diffuse and homogeneous enhancement in the pure arterial phase, which became progressively hypoechoic relative to the adjacent liver parenchyma during the portal vein and late phases (mixed vascular phase), and showed a contrast defect with an unclear border in the Kupffer phase. Histologically we diagnosed this hepatic tumor as CoCC. In light of the above findings and the rarity of CoCC, it is helpful to incorporate the results of several imagings, such as CT, MRI, angiography and CEUS with a second-generation contrast agent when clinically diagnosing CoCC.