Contrast-Enhanced Ultrasound Features of Primary Hepatic Lymphoepithelioma-Like Carcinoma: Comparison with Hepatocellular Carcinoma

Abstract

Background: Primary hepatic lymphoepithelioma-like carcinoma (LELC) is a malignant tumor with a low incidence, but the number of case reports has increased in recent years. The prognosis of hepatic LELC is better than hepatocellular carcinoma (HCC). The differentiation between hepatic LELC and HCC has clinical value during follow-up treatment. The purpose of our study was to compare contrast-enhanced ultrasound (CEUS) imaging features in patients with hepatic LELC and HCC. Methods: Twelve patients with an average age of 60.1±9.5 years and histopathologically confirmed hepatic LELC were included in the study. Forty-three patients with an average age of 57.4±9.0 years and a histopathological diagnosis of HCC were designated as the control group by means of propensity score matching (1:4). The clinical data, B-mode ultrasound (BMUS), and CEUS features were retrospectively analyzed between patients with hepatic LELC and HCC. Results: The serum a-fetoprotein (58.1% [25/43] vs.16.7% [2/12]; p=0.017) and des-gamma-carboxy prothrombin levels (74.4% [32/43] vs.16.7% [2/12]; p=0.001) were not significantly elevated in patients with hepatic LELCs compared to HCCs. LELCs were mainly hypoechoic based on BMUS, while the echogenicity of HCCs varied (p=0.016). A halo sign was less common in patients with hepatic LELCs than HCCs (16.7% [2/12] vs. 58.1% [25/43]; p=0.011). Of hepatic LELCs, 75% (9/12) had homogeneous hyperenhancement based on CEUS, whereas 58.1% (25/43) of HCCs had heterogeneous hyperenhancement (p=0.004). Early washout was noted in 91.7% (11/12) of hepatic LELCs compared to 46.5% (20/43) of HCCs (p=0.005). Furthermore, hepatic LELCs were more likely to exhibit peripheral rim-like hyperenhancement (83.3% [10/12] vs. 11.6% [5/43]; p < 0.001). Conclusion: BMUS and CEUS are helpful in discriminating between hepatic LELC and HCC. A hypoechoic mass, the rare halo sign, homogeneous hyperenhancement in the arterial phase, higher frequencies of early washout, and peripheral rim-like hyperenhancement are useful ultrasound features that can help differentiate hepatic LELCs from HCCs.