The imaging features in ultrasonography of cholangiolocarcinoma: correlation with pathological findings.

Abstract

Background: Cholangiolocellular carcinoma (CoCC) is rare primary liver cancer and currently considered to originate from hepatic progenitor cells. The purpose of this study was to evaluate the imaging features in ultrasonography of cholangiolocellular carcinoma of the liver. Methods: Six cases of surgically resected cases of CoCC from 2 institutions were retrospectively evaluated. All of the six patients underwent contrast-enhanced ultrasonography (CEUS), dynamic CT, Gd-EOB-DTPA MRI and angio-CT including CT during arterioportography (CTAP) and CT during hepatic arteriography (CTHA). Histological evaluation was also performed and was correlated with imaging findings. Results: In the early vascular phase of CEUS, the lesions presented diffuse and homogeneous enhancement in 2 cases with less than 2cm in tumor diameter, but in 4 cases with lager than 2cm, the lesions presented heterogeneous enhancement. From the late vascular phase to Kupffer phase, the continued existence of portal veins or tiny spots of portal flow was identified in the tumors. This feature, portal venous penetration within the tumor, was also observed in Angio CT, but not observed in dynamic CT and Gd-EOB-DTPA MRI. Conclusion: The absence of a fibrous capsule, the absence of tumor necrosis and the presence of portal venous penetration within the tumor also appear to be characteristic features in CEUS. But it may be some difference in the enhancement pattern in vascular phase with tumor size. CEUS is considered to be useful in the diagnosis of CoCC.