A 60-year-old female was admitted to our hospital because of obstructive jaundice. She had undergone a right hepatectomy resulting from a single small (approximately 3 cm) hepatocellular carcinoma (HCC) 6 months previously. Laboratory data values were abnormally increased as follows: serum bilirubin level, 7.7 mg/dL (normal, <1.0 mg/dL); serum alkaline phosphatase, 295 IU/L (normal, 20-120); aspartate aminotransferase, 55 (normal, 5-40); gamma-glutamyl transferase, 318 (normal, 10-66); amylase, 165 (normal, 28-116); lipase, 78 (normal, 0-60), white blood cell count, 16,400 cells/mm3 (normal, 3.9-9.7 × 103); and alfa-fetoprotein, 10.82 ng/mL (normal, 0-6). Levels of all other serum tumor markers, including carcinoembryonic antigen, carbohydrate antigen (CA) 125, and CA 19-9, were within normal limits.
A dynamic series of computed tomography scans revealed a polypoid lesion in the distal common bile duct (CBD), which showed early enhancement on the arterial phase and washout on the portal venous phase (Fig. A). Endoscopic retrograde cholangiopancreatography showed marked CBD dilatation with a round filling defect in the distal CBD (Fig. B). On endoscopy, a whitish polypoid lesion was visible in the distal CBD (Fig. C). There were no other abnormal lesions in the abdomen. A lesion specimen, obtained by an endoscopy-guided biopsy in the distal CBD, displayed tumor cells proliferating in a trabecular-to-compact manner without glandular differentiation or mucin-containing cells (hematoxylin and eosin; magnification, ×10 and ×100; Fig. D). The tumor was diagnosed as metastatic HCC without a choloangiocellular carcinoma component.
HCC commonly occurs in a cirrhotic liver, and invasion of the intrahepatic bile duct is not rare.1 Icteric HCC (iHCC) might invade the biliary tree by three different mechanisms of action: direct tumor infiltration to the biliary tree, infiltration from a periportal tumor, and intraductal tumor growth. 2 There were several reports about radiographic findings of biliary invasion from HCC. 3 However, to the best of our knowledge, endoscopic presentation of intraductal metastasis into the distal CBD from HCC has not previously been reported. On various imaging modalities, iHCC appears as an expansile soft-tissue mass that causes dilatation of the bile duct. 1 Our case mimicked the intraductal mass-forming type of cholangiocarcinoma. Presentation of the clinical and radiologic characteristics of iHCC may help narrow the differential diagnoses for this condition. However, the radiological findings are nonspecific, and a biopsy may be required to achieve a conclusive histopathological diagnosis.