Bile Duct Hamartomas: US, CT and MR Findings in Eight Patients, Focusing on the US Findings

ABSTRACT

PURPOSE: To describe the US, CT and MR findings in eight patients with bile duct hamartomas. MATERIALS AND METHODS: Bile duct hamartomas were diagnosed in eight patients (5 men and 3 women; age range, 41-69 years; mean age, 56 years) by liver biopsy. The US, CT and MR findings were retrospectively reviewed. RESULTS: Ultrasonographically, the bile duct hamartomas presented diffuse inhomogeneous and coarse echo texture with focal lesions, including bright spotty echoes or small hyperechoic nodules (n=7), hypoechoic nodules (n=7) and comet-tail echo (n=3) in seven patients. 16 of the 39 definable hypoechoic nodules that ranged in size from 5 mm to 16mm showed posterior enhancement. CT revealed innumerable hypodense nodules measuring 2-5 mm (n=3), 2-13 mm (n=1), 2-15 mm (n=2) and 2-18 mm (n=1) in seven patients. They were usually irregular in shape and showed no enhancement, but became more apparent after the administration of intravenous contrast medium. The innumerable hypodense nodules on enhanced CT scans were uniformly (n=5) or nonuniformly (n=2) distributed throughout the liver. In four patients, MR images showed multiple small cyst-like lesions 2-13 mm in diameter. These small cystlike lesions were much more apparent on T2-weighted images or MR cholangiography. The diagnosis was made by either core-needle or wedge biopsy. In one patient, a small single lesion on the liver surface was not visible on the imaging studies. Pathologic examination revealed multiple bile duct hamartomas of varying size or microhamartomas. CONCLUSION: Although the bile duct hamartomas on CT and MR presented as numerous intrahepatic, small cyst-like lesions, they on US showed variable findings consisting of inhomogeneous and coarse echo texture with focal lesions, including bright spotty echoes or small hyperechoic nodules, hypoechoic nodules, and comet-tail echoes.