Early bile duct carcinoma: comparison of imaging features with pathologic findings

PURPOSE: To retrospectively evaluate the imaging features of early bile duct carcinoma and to compare these features with histopathologic findings. MATERIALS AND METHODS: The institutional review board did not require its approval or informed patient consent for this study. Twenty-one patients (13 men, eight women; mean age, 60 years; range, 48-75 years) with early bile duct carcinoma that was surgically resected and histopathologically confirmed were included. Ultrasonography (US) was performed in 15 patients, computed tomography (CT) in 21, cholangiography in 18, and magnetic resonance (MR) cholangiography in six. Two radiologists retrospectively reviewed imaging features by consensus; they compared growth pattern of tumors, integrity of the bile duct wall that harbored the tumor, and periductal infiltration with histopathologic findings. RESULTS: Pathologic specimens showed intraluminal tumor growth in all cases. Tumors were confined to the mucosa in 11 patients and involved the fibromuscular layer in 10 patients. In four of the 10 intrahepatic cholangiocarcinomas, four of the five hilar cholangiocarcinomas, and six of the six extrahepatic cholangiocarcinomas, there were intraductal tumor masses and the wall of the tumor-bearing bile ducts was preserved without periductal infiltration on US and CT images. On cholangiograms and MR cholangiograms, tumors were better delineated but the wall invasion could not be evaluated. No difference in image findings was found between carcinoma confined to the mucosa and carcinoma involving the fibromuscular layer. CONCLUSION: Imaging features of early bile duct carcinoma are a tumor mass in the bile duct lumen and integrity of the tumor-bearing bile duct wall without infiltration outside the wall.