Contrast-enhanced ultrasound features of hepatic sarcomatoid carcinoma different from hepatocellular carcinoma.

ABSTRACT

BACKGROUND: Hepatic sarcomatoid carcinoma (HSC) is a rare malignancy of the liver. The ultrasound and clinical features of HSC have not been determined. OBJECTIVE: To investigate and compare the ultrasound and clinical features of HSC and hepatocellular carcinoma (HCC), and to reveal the valuable features of HSC. METHODS: The ultrasound features and clinical data of pathologically proven HSC (n = 37) were compared with HCC (n = 92) in a matching ratio of 14 using the propensity score (age, gender and tumor size). RESULTS: The HSC patients were more likely to accompany with clinical symptoms and vascular invasion than HCC patients (40.5% vs 17.4%, 24.3% vs 6.5%, P < 0.05). The size of HSCs was significantly larger than that of HCCs (P < 0.05). The proportion of patients with elevated alpha-fetoprotein was significantly lower in HSC (35.1% vs 54.3%, P < 0.05). On gray-scale ultrasound images, the HSCs were more likely to demonstrate as indistinct margin and irregular shape lesions compared to HCCs (78.4% vs 48.8%; 70.3% vs 23.9%, P < 0.05). Under color Doppler flow imaging (CDFI), the blood flow signals were more frequently detected in HSC lesions (75.7% vs 56.5%, P < 0.05). Resistance index (RI) was higher in HSCs than in HCCs [0.78 (0.70,0.82) vs 0.70 (0.62,0.76), P < 0.05]. On contrast-enhanced ultrasound (CEUS), HSCs mainly showed entirety heterogeneous hyper-enhancement (48.6%), entirety homogeneous enhancement (18.9%), peripheral and internal septal enhancement (18.9%). The incidence of non-enhanced areas inside HSC lesions was higher than that inside HCC lesions (56.8% vs 31.5%, P < 0.05). During the portal venous and late phases, most of the lesions revealed hypo-enhancement in both groups, whereas earlier washout was observed in HSCs [43.0 s (30.5,58.0) vs 60.0 s (46.3,100.0), P < 0.05]. CONCLUSIONS: CEUS features are useful in preoperative and non-invasive differentiation of hepatic sarcomatoid carcinoma and hepatocellular carcinoma.