Papillary neoplasms of the bile duct that mimic biliary stone disease.

Papillary tumors of the bile duct are intraductal tumors with innumerable minute, frondlike papillary projections. These tumors may be either fixed to or detached from the bile duct wall. However, because the papillary projections on the surface of papillary tumors are long and slender, the tumors are friable and slough easily. The sloughed tumor fragments may float within the bile ducts, resulting in intermittent partial biliary obstruction and mimicking bile duct stones at clinical examination and at ultrasonography (US), computed tomography (CT), and cholangiography. A tumor manifests radiologically as thickening and irregularity of the bile duct wall or as a fixed or sloughed intraductal mass. A nonshadowing intraductal echogenic cast seen at US, an intraductal noncalcified soft-tissue mass with asymmetric wall thickening seen at CT, and an intraductal mass with a papillary surface and a serrated bile duct margin seen at cholangiography are all appearances that suggest a papillary tumor and may be helpful in differentiating a tumor from a bile duct stone. Copyright RSNA, 2003