[A case of intraductal papillary neoplasm of the bile duct preoperatively diagnosed using contrast-enhanced endoscopic ultrasonography].

A 71-year-old man was referred to our hospital and was diagnosed with jaundice and a liver function disorder. Although we suspected an intraductal papillary neoplasm of the bile duct (IPNB)-derived caudate branches on the basis of contrast-enhanced CT, MRI, and endoscopic retrograde cholangiopancreatography, we could not clearly identify the tumor. Therefore, we examined the lesion using endoscopic ultrasonography (EUS). We could visualize an iso-hyperechoic elevated tumor in the caudate branches. The tumor was observed as a hypervascular lesion using contrast-enhanced EUS, which is useful in preoperatively diagnosing IPNB and detecting the presence of lesions.