Choledochal cyst: sonographic evaluation of an unusual case.

The preeminence of sonography in the diagnosis of obstructive jaundice has already been established. Earlier reports have described a variety of radiologic modalities used to establish the diagnosis of choledochal cyst. Our case illustrates the usefulness of sonography in differential consideration, though either transhepatic or operative cholangiography is necessary to further define the point and nature of the obstructive process and to determine that the cyst communicates with the common bile duct.