Objective: To identify laboratory and sonographic features capable of differentiating hepatocellular carcinoma (HCC) invading the bile duct from intraductal cholangiocarcinoma (IDCCC).
Methods: Nine patients with HCC invading the bile duct and 8 patients with IDCCC were found in our radiologic and pathologic database. Laboratory (alpha-fetoprotein, cancer antigen 19-9, total bilirubin, and alkaline phosphatase) and sonographic findings were retrospectively reviewed by 2 reviewers by consensus. Sonographic findings included the presence and echo texture of parenchymal masses, the margin and echo texture of intraductal masses, continuity between parenchymal and intraductal masses, cystic ductal dilatation or wall thickening of the bile duct, and the presence of associated chronic liver disease.
Results: Significant differences were found in the levels of total bilirubin (14 versus 3.5 mg/dL), alpha-fetoprotein (2984 versus 5 ng/mL), and cancer antigen 19-9 (8574 versus 1861 U/mL) in HCC and IDCCC (P <.05). Echogenicity of the intraductal masses was iso or low in 8 (88.9%) of 9 HCCs and 3 (37.5%) of 8 IDCCCs (P <.05). In all 7 patients with HCC but in no patient with IDCCC, the parenchymal masses were contiguous with the intraductal masses (P <.05). Cystic ductal dilatation of bile duct was seen in 8 (88.9%) of 9 HCCs and 3 (37.5%) of 8 IDCCCs (P <.05). All 9 (100%) of 9 HCCs and 3 (37.5%) of 8 IDCCCs were associated with chronic liver disease (P <.05). Parenchymal masses occurred in 7 patients with HCC (77.8%) and in 3 patients with IDCCC (37.5%), but the difference was not statistically significant (P =.153). The margins of the intraductal masses were smooth in all 9 (100%) of 9 HCCs and lobulated in 3 (37.5%) of 8 IDCCCs (P =.082).
Conclusions: Combined interpretation of laboratory and sonographic features may help in the differentiation of HCC with bile duct invasion and IDCCC.