Bile duct wall metastasis from micropapillary variant transitional cell carcinoma of the urinary bladder mimicking primary hilar cholangiocarcinoma.

Biliary obstruction can be caused by primary bile duct malignancies as well as malignancies arising in adjacent organs such as the papilla, gallbladder, and pancreas.1 Infrequently, malignant biliary tract obstruction can be caused by a metastatic lesion from a distant tumor, usually through the mechanism of extrinsic compression by tumor-infiltrated lymph nodes in the perihilar, pericholedochal, and/or hepatoduodenal areas.1,2 The sites of primary tumors that account for most cases of biliary obstruction caused by metastasis are the stomach, colon, breast, lung, and cervix. Malignant biliary obstruction can also be caused by intrabiliary metastasis within the submucosal layer of the bile duct, although this is extremely rare. This type of intrabiliary metastasis results in unique cholangiographic findings that mimic primary cholangiocarcinoma. Reported here is the case of a patient who presented with obstructive jaundice caused by bile duct wall metastasis of micropaillary variant transitional cell carcinoma of the urinary bladder.ope