Ultrasonography of intrahepatic bile duct adenoma with renal cell carcinoma: correlation with pathology.

Intrahepatic bile duct adenoma (BDA) is a relatively rare benign tumor. Most cases are incidentally discovered during surgery or autopsy. We report here the co-existence of renal cell carcinoma and BDA mimicking metastasis in a 30-year-old female. An isoechoic nodule with a hypoechoic rim sized 10 × 9 mm was observed by ultrasonography in S2 of the liver. On contrast-enhanced ultrasonography (CEUS), the mass was enhanced in the early vascular phase and a defect with a clear border appeared in the post-vascular phase. We present the ultrasonography findings of BDA, including those yielded by CEUS using Sonazoid, along with the gross and microscopic pathological correlation.