Steatohepatitic hepatocellular carcinoma (SH-HCC) is a distinctive histologic variant of HCC for the presence of steatohepatitis. This study intended to evaluate the contrast-enhanced imaging features and clinicopathological characteristics of 26 SH-HCCs in comparison with 26 age-and-sex-matched non-SH-HCCs. The frequency of obesity (34.6%, p = 0.048) and type 2 diabetes mellitus (23.1%, p = 0.042) were significantly higher in SH-HCC patients. As seen via B-mode ultrasound (BMUS), SH-HCCs were predominantly hyperechoic (65.4%, p = 0.002) lesions, while non-SH-HCCs were mainly hypo-echoic. As seen via contrast-enhanced ultrasound (CEUS), 96.2% of SH-HCCs exhibited hyperenhancement in the arterial phase. During the portal venous and late phase, 88.5% of SH-HCCs showed late and mild washout. Consequently, most SH-HCCs and all non-SH-HCCs were categorized as LR-4 or LR-5. As seen via magnetic resonance imaging (MRI), a signal drop in the T1WI opposed-phase was observed in 84.6% of SH-HCCs (p = 0.000). Notably, diffuse fat in mass was detected in 57.7% (15/26) SH-HCCs (p < 0.001). As seen via contrast-enhanced MRI (CEMRI), most of the SH-HCCs and non-SH-HCCs exhibited heterogeneous hyperenhancement in the arterial phase (80.8% versus 69.2%, p = 0.337). During the delayed phase, 76.9% SH-HCCs and 88.5% non-SH-HCCs exhibited hypo-enhancement. Histopathologically, the rate of microvascular invasion (MVI) was significantly lower in SH-HCCs than non-SH-HCCs (42.3% versus 73.1%, p = 0.025). The frequency of hepatic steatosis >5% in non-tumoral liver parenchyma of SH-HCCs was significantly higher than in non-SH-HCCs (88.5% versus 26.9%, p = 0.000). Additionally, the fibrotic stages of S0, S1 and S2 in SH-HCCs were significantly higher than in non-SH-HCCs (p = 0.044). During follow-up, although the PFS of SH-HCC patients was significantly longer than non-SH-HCC patients (p = 0.046), for the overall survival rate of SH-HCC and non-SH-HCC patients there was no significant difference (p = 0.162). In conclusion, the frequency of metabolism-related diseases in SH-HCC patients was significantly higher than in non-SH-HCC patients. The imaging features of SH-HCCs combined the fatty change and typical enhancement performance of standard HCC as seen via CEUS/CEMRI.

Isolated hepatic malignant melanoma with undetermined origin is relatively rare and the imaging findings vary significantly in published studies. In this report, we described an elderly male patient with pulmonary tuberculosis who was diagnosed with isolated hepatic malignant melanoma with undetermined origin by ultrasound-guided percutaneous coarse needle biopsy (US-CNB). The hepatic melanoma was detected accidentally on chest CT. On contrast-enhanced ultrasound (CEUS), it presented an enhancement pattern of fast washin and slow washout. However, on magnetic resonance imaging (CEMRI), it showed non-rim hyperenhancement in the arterial phase but hypointensity in the late phase, mimicking hepatocellular carcinoma. With inconsistent results, the patient underwent fluorine-18-fluro-2-deoxy-D-glucose-positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT). The mass showed mild ¹⁸F-FDG uptake with SUVmax of 4.7, and hypermetabolic nodules were observed in the lung, chest wall, thoracic vertebra, and pelvis. Due to the advanced stage of the tumor, US-CNB was performed to acquire a pathological diagnosis. The immunohistochemical staining suggested malignant melanoma. Of note, no primary tumor was revealed. Finally, the patient refused systemic therapy and died from tumor progression seven months later. Hence, CEUS and CEMRI is fundamental in the diagnosis of hepatic melanoma, and PET-CT is helpful in clinical staging. For controversial results, US-CNB is required to establish the pathological diagnosis.