To investigate the findings of conventional and contrast-enhanced ultrasound of extrahepatic abdominal metastasis in patients with primary liver cancer (PLC) after liver transplantation (LT).

Clinical data of 50 PLC patients with extrahepatic abdominal metastases after LT admitted to the Third Affiliated Hospital of Sun Yat-sen University from December 2008 to December 2018 were retrospectively analyzed. Among them, 49 patients were male and 1 female, aged (51±9) years on average. Primary diseases: 49 cases were diagnosed with hepatocellular carcinoma and 1 case of cholangiocarcinoma. The informed consents of all patients were obtained and the local ethical committee approval was received. The patients were followed up after LT by receiving conventional and/or contrast-enhanced ultrasonography. The ultrasonographic manifestations of extrahepatic abdominal metastases were summarized.

The time of initial detection of metastatic lesions by ultrasound was 17 d-50 months with a median time of 7 months. The diameter of metastatic lesions was ranged from 0.7 to 11.1 cm with a median diameter of 2.6 cm when first detected by ultrasound. Multiple metastases were found in 45 cases, of whom 35 cases were complicated with intrahepatic metastases. Metastatic sites: 30 cases of lymph nodes in the porta hepatis, 20 cases of lymph nodes in the mesentery. The metastatic lesions in 36 cases were in regular shape and had clear boundary with surrounding tissues. And the metastatic lesions in 12 cases had no clear boundary. Homogeneous hypoecho was detected within the lesions in 47 cases and irregular liquefaction necrosis in 3 cases without evident signs of calcification. Color doppler flow signals were found inside the lesions in 15 cases by color Doppler ultrasound. 16 cases also received contrast-enhanced ultrasonography. Lesions with uneven enhancement were found in 13 cases, including 7 cases of peripheral thick annular enhancement, 5 cases of irregular enhancement and 1 case of irregular band enhancement.

Ultrasonography can effectively detect the extrahepatic abdominal metastases of PLC after LT. Most of the metastatic lesions are multiple, with well-defined boundary and homogeneous hypoechoic masses, whereas color blood flow signals can be detected in small portion of lesions.